LNT


Line plots across dimensions of each concept
Line plots across concepts
Tables

Table of contents



us-gaap:CommonStockValue
dei:LegalEntity

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareBasicAndDiluted

us-gaap:AllocatedShareBasedCompensationExpense
dei:LegalEntity

us-gaap:CostOfGoodsAndServicesSold
dei:LegalEntity

us-gaap:CostsAndExpenses
dei:LegalEntity

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
dei:LegalEntity

us-gaap:IncomeTaxExpenseBenefit
dei:LegalEntity

us-gaap:IncomeTaxesPaidNet
dei:LegalEntity

us-gaap:InterestExpense
dei:LegalEntity

us-gaap:InterestPaidNet
dei:LegalEntity

us-gaap:NetIncomeLoss
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementEquityComponents

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementEquityComponents
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments
us-gaap:StatementEquityComponents

us-gaap:NonoperatingIncomeExpense
dei:LegalEntity

us-gaap:OperatingIncomeLoss
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementBusinessSegments
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments

us-gaap:OtherComprehensiveIncomeLossNetOfTax
us-gaap:StatementEquityComponents

us-gaap:OtherNonoperatingIncomeExpense
dei:LegalEntity

us-gaap:RegulatedAndUnregulatedOperatingRevenue
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementBusinessSegments
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
dei:LegalEntity
dei:LegalEntity, us-gaap:MajorCustomers, us-gaap:StatementBusinessSegments
dei:LegalEntity, us-gaap:StatementBusinessSegments
us-gaap:MajorCustomers, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments

us-gaap:Revenues

us-gaap:UnregulatedOperatingRevenue

us-gaap:Assets
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementBusinessSegments
us-gaap:ConsolidatedEntities
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus
us-gaap:StatementBusinessSegments

us-gaap:LiabilitiesAndStockholdersEquity
dei:LegalEntity
us-gaap:ConsolidatedEntities

us-gaap:StockholdersEquity
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementEquityComponents
us-gaap:ConsolidatedEntities
us-gaap:StatementEquityComponents

us-gaap:AssetsCurrent
dei:LegalEntity
us-gaap:ConsolidatedEntities
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:CashAndCashEquivalentsAtCarryingValue
dei:LegalEntity

us-gaap:AccountsReceivableNetCurrent
dei:LegalEntity

us-gaap:InventoryRawMaterialsAndSupplies
dei:LegalEntity

us-gaap:OtherAssetsCurrent
dei:LegalEntity
us-gaap:ConsolidatedEntities
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:AssetsNoncurrent

us-gaap:PropertyPlantAndEquipmentNet
dei:LegalEntity

us-gaap:LongTermInvestments
us-gaap:ConsolidatedEntities

us-gaap:OperatingLeaseRightOfUseAsset
dei:LegalEntity

us-gaap:OtherAssetsNoncurrent
dei:LegalEntity
us-gaap:ConsolidatedEntities

us-gaap:AccountsPayableCurrent
dei:LegalEntity

us-gaap:LiabilitiesCurrent
dei:LegalEntity
us-gaap:ConsolidatedEntities
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:LongTermDebtCurrent

us-gaap:OperatingLeaseLiabilityCurrent

us-gaap:OtherLiabilitiesCurrent
dei:LegalEntity
us-gaap:ConsolidatedEntities

us-gaap:TaxesPayableCurrent
dei:LegalEntity
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:LiabilitiesNoncurrent
dei:LegalEntity, us-gaap:FairValueByMeasurementBasis
us-gaap:LongTermDebt
us-gaap:FairValueByMeasurementBasis

us-gaap:LongTermDebtNoncurrent
dei:LegalEntity

us-gaap:DeferredIncomeTaxLiabilitiesNet
dei:LegalEntity

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:MinorityInterest

us-gaap:OtherLiabilitiesNoncurrent
dei:LegalEntity
us-gaap:ConsolidatedEntities

us-gaap:OperatingLeaseLiabilityNoncurrent
dei:LegalEntity

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive
dei:LegalEntity

us-gaap:OperatingLeaseLiability
dei:LegalEntity

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue
dei:LegalEntity

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
dei:LegalEntity

us-gaap:StockholdersEquity
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementEquityComponents
us-gaap:ConsolidatedEntities
us-gaap:StatementEquityComponents

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
dei:LegalEntity

us-gaap:CommonStockValue
dei:LegalEntity

us-gaap:AdditionalPaidInCapitalCommonStock
dei:LegalEntity
us-gaap:ConsolidatedEntities
us-gaap:CommonStocksIncludingAdditionalPaidInCapital

us-gaap:RetainedEarningsAccumulatedDeficit
dei:LegalEntity
us-gaap:ConsolidatedEntities

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax
us-gaap:EquityMethodInvestmentNonconsolidatedInvestee
us-gaap:MinorityInterest

us-gaap:NetCashProvidedByUsedInOperatingActivities
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInInvestingActivities
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInFinancingActivities
dei:LegalEntity

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
dei:LegalEntity

us-gaap:DepreciationDepletionAndAmortization
dei:LegalEntity

us-gaap:IncreaseDecreaseInAccountsReceivable
dei:LegalEntity

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInOperatingActivities
dei:LegalEntity

us-gaap:NetIncomeLoss
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementEquityComponents

us-gaap:NetCashProvidedByUsedInInvestingActivities
dei:LegalEntity

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment
dei:LegalEntity

us-gaap:NetCashProvidedByUsedInFinancingActivities
dei:LegalEntity

us-gaap:ProceedsFromIssuanceOfLongTermDebt
dei:LegalEntity

us-gaap:RepaymentsOfLongTermDebt
dei:LegalEntity

us-gaap:PaymentsOfDividendsCommonStock
dei:LegalEntity

us-gaap:EffectiveIncomeTaxRateContinuingOperations
dei:LegalEntity
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod

us-gaap:DeferredTaxLiabilities
dei:LegalEntity

us-gaap:DeferredTaxAssetsNet
dei:LegalEntity

us-gaap:DeferredTaxAssetsValuationAllowance
dei:LegalEntity

us-gaap:ProceedsFromRepaymentsOfShortTermDebt
dei:LegalEntity
dei:LegalEntity, us-gaap:Range
lnt:AverageProceedsFromSaleAndCollectionOfReceivables
dei:LegalEntity
lnt:CollectionsReinvestedInReceivables
dei:LegalEntity
lnt:CreditLossesNetOfRecoveries
us-gaap:LongTermContractForPurchaseOfElectricPower
lnt:LongtermContractforPurchaseofElectricPowerBuyoutPayment
us-gaap:StatementScenario, us-gaap:LongTermContractForPurchaseOfElectricPower
dei:LegalEntity, us-gaap:RegulatoryLiability
lnt:NumberOfCustomersWithoutPowerDerechoWindstorm

us-gaap:AssetRetirementObligationAccretionExpense
dei:LegalEntity

us-gaap:AssetRetirementObligationLiabilitiesIncurred
dei:LegalEntity

us-gaap:AssetRetirementObligationLiabilitiesSettled
dei:LegalEntity

us-gaap:AssetRetirementObligationRevisionOfEstimate

us-gaap:CapitalExpendituresIncurredButNotYetPaid
dei:LegalEntity

us-gaap:CommonStockDividendsPerShareDeclared

us-gaap:ConsiderationReceivedForBeneficialInterestObtainedForTransferringFinancialAsset
dei:LegalEntity

us-gaap:CumulativeEffectOnRetainedEarningsNetOfTax1
us-gaap:AdjustmentsForNewAccountingPronouncements, us-gaap:StatementEquityComponents

us-gaap:DeferredIncomeTaxesAndTaxCredits
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanInterestCost
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost
us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanServiceCost
us-gaap:RetirementPlanType

us-gaap:DepreciationAndAmortization
dei:LegalEntity
dei:LegalEntity, us-gaap:Energy, us-gaap:TradingActivityByType
us-gaap:DerivativeNonmonetaryNotionalAmountEnergyMeasure
us-gaap:Energy, us-gaap:TradingActivityByType
dei:LegalEntity, us-gaap:Energy, us-gaap:TradingActivityByType
us-gaap:DerivativeNonmonetaryNotionalAmountMass
us-gaap:Energy, us-gaap:TradingActivityByType
dei:LegalEntity, us-gaap:Energy, us-gaap:TradingActivityByType
us-gaap:DerivativeNonmonetaryNotionalAmountVolume
us-gaap:Energy, us-gaap:TradingActivityByType

us-gaap:DividendsCommonStock
dei:LegalEntity
dei:LegalEntity, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:DividendsPreferredStock
dei:LegalEntity

us-gaap:EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense
dei:LegalEntity
dei:LegalEntity, us-gaap:Range, us-gaap:PublicUtility
us-gaap:EnvironmentalExitCostsAnticipatedCost
us-gaap:Range, us-gaap:PublicUtility
dei:LegalEntity, us-gaap:FairValueByAssetClass
us-gaap:FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
us-gaap:FairValueByAssetClass
dei:LegalEntity, us-gaap:FairValueByAssetClass
us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
us-gaap:FairValueByAssetClass
dei:LegalEntity, us-gaap:FairValueByAssetClass
us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
us-gaap:FairValueByAssetClass
dei:LegalEntity, us-gaap:FairValueByAssetClass
us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
us-gaap:FairValueByAssetClass
dei:LegalEntity, us-gaap:FairValueByAssetClass
us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
us-gaap:FairValueByAssetClass

us-gaap:IncomeLossFromEquityMethodInvestments
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction
dei:LegalEntity

us-gaap:IncreaseDecreaseInDeferredIncomeTaxes
dei:LegalEntity

us-gaap:IncreaseDecreaseInOtherCurrentLiabilities
dei:LegalEntity
dei:LegalEntity
us-gaap:IncreaseDecreaseInOtherRegulatoryAssets

us-gaap:IncreaseDecreaseInPensionAndPostretirementObligations

us-gaap:IncreaseDecreaseInRegulatoryLiabilities
dei:LegalEntity
us-gaap:Ownership
us-gaap:LimitedLiabilityCompanyLLCOrLimitedPartnershipLPMembersOrLimitedPartnersOwnershipInterest

us-gaap:LongTermPurchaseCommitmentAmount
us-gaap:Ownership
us-gaap:OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal

us-gaap:OtherCostAndExpenseOperating

us-gaap:OtherNoncashIncomeExpense
dei:LegalEntity

us-gaap:PaymentsForProceedsFromOtherInvestingActivities
dei:LegalEntity

us-gaap:PaymentsToAcquireOtherProductiveAssets

us-gaap:ProceedsFromCollectionOfRetainedInterestInSecuritizedReceivables
dei:LegalEntity
dei:LegalEntity
us-gaap:ProceedsFromContributionsFromParent
dei:LegalEntity, us-gaap:StatementEquityComponents

us-gaap:ProceedsFromIssuanceOfCommonStock
us-gaap:StatementEquityComponents

us-gaap:ProceedsFromPaymentsForOtherFinancingActivities
dei:LegalEntity
dei:LegalEntity, us-gaap:RegulatoryAgency
us-gaap:ProceedsFromRefundsFromSuppliersOfMaterial
dei:LegalEntity, us-gaap:Range
us-gaap:ProceedsFromSaleAndCollectionOfReceivables

us-gaap:PublicUtilitiesAllowanceForFundsUsedDuringConstructionAdditions
dei:LegalEntity

us-gaap:RegulatedOperatingRevenueElectricNonNuclear
dei:LegalEntity

us-gaap:RegulatedOperatingRevenueGas
dei:LegalEntity

us-gaap:RegulatedOperatingRevenueOther
dei:LegalEntity
dei:LegalEntity, us-gaap:CounterpartyName, us-gaap:RelatedPartyTransaction, us-gaap:RelatedPartyTransactionsByRelatedParty
us-gaap:RelatedPartyTransactionAmountsOfTransaction
us-gaap:CounterpartyName, us-gaap:RelatedPartyTransaction, us-gaap:RelatedPartyTransactionsByRelatedParty
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue

us-gaap:ShortTermDebtWeightedAverageInterestRateOverTime
dei:LegalEntity

us-gaap:ShorttermDebtAverageOutstandingAmount
dei:LegalEntity

us-gaap:ShorttermDebtMaximumAmountOutstandingDuringPeriod
dei:LegalEntity
us-gaap:SubsidiarySaleOfStock
us-gaap:StockIssuedDuringPeriodSharesNewIssues

us-gaap:StockholdersEquityOther
us-gaap:StatementEquityComponents

us-gaap:TaxesExcludingIncomeAndExciseTaxes
dei:LegalEntity

us-gaap:UtilitiesOperatingExpenseFuelUsed
dei:LegalEntity

us-gaap:UtilitiesOperatingExpenseGasAndPetroleumPurchased
dei:LegalEntity
dei:LegalEntity
us-gaap:UtilitiesOperatingExpenseMaintenanceAndOperations
us-gaap:AwardType
us-gaap:WeightedAverageNumberDilutedSharesOutstandingAdjustment
dei:LegalEntity
lnt:AccumulatedAmortizationOnPublicUtilitiesPropertyPlantAndEquipmentLeased

lnt:AccumulatedDepreciationOnPropertyPlantAndEquipmentNonRegulatedBusinessLine1

lnt:AccumulatedDepreciationOnPropertyPlantAndEquipmentNonRegulatedBusinessLine2
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
lnt:AllowanceForDoubtfulAccountsReceivableSold
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
lnt:CashProceedsFromReceivablesSold

lnt:CommonStockHeldInTrustWeightedAverageValuePerShare

lnt:CommonStockPercentageInAssetsHeldSavingPlans
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
lnt:CustomerAccountsReceivableSoldAmount
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
lnt:DeferredProceedsOfReceivablesSold
dei:LegalEntity, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis
dei:LegalEntity, us-gaap:RetirementPlanType
lnt:DefinedBenefitPlanAmountsRecognizedInRegulatoryAssetAndRegulatoryLiabilityAndOtherComprehensiveIncomeNetGainLossBeforeTax
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
lnt:DefinedBenefitPlanAmountsRecognizedInRegulatoryAssetAndRegulatoryLiabilityAndOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
lnt:DefinedBenefitPlanAmountsRecognizedInRegulatoryAssetsRegulatoryLiabilitiesAndOtherComprehensiveIncome
us-gaap:RetirementPlanType
dei:LegalEntity
lnt:DefinedBenefitPlanRegulatoryAssetAllocatedFromCorporateServices

lnt:FairValueOfDeferredProceedsOfReceivablesSold
dei:LegalEntity
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
dei:LegalEntity, us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel

lnt:InvestmentsBusinessLine1

lnt:NetUtilityPlant
dei:LegalEntity
us-gaap:ConsolidatedEntities
lnt:ParentCompanyInvestmentInConsolidatedSubsidiaries
dei:LegalEntity, us-gaap:RetirementPlanType
lnt:PensionAndOtherPostretirementDefinedBenefitPlansNonCurrentAssets
us-gaap:RetirementPlanType

lnt:PropertyPlantAndEquipmentNonregulatedBusinessLine1

lnt:PropertyPlantAndEquipmentNonregulatedBusinessLine2
dei:LegalEntity
lnt:PublicUtilitiesAllowanceForFundsUsedDuringConstructionReturnEarnedExpectedPercentageOfEstimatedConstructionWorkInProcessNextTwelveMonths

lnt:PublicUtilitiesPropertyPlantAndEquipmentElectric
dei:LegalEntity

lnt:PublicUtilitiesPropertyPlantAndEquipmentGas
dei:LegalEntity

lnt:PublicUtilitiesPropertyPlantAndEquipmentGeneral
dei:LegalEntity
dei:LegalEntity
lnt:PublicUtilitiesPropertyPlantAndEquipmentLeased
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
lnt:ReceivablesSold
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
lnt:SaleofAccountsReceivableProgramCapacityAvailable
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
lnt:UnbilledUtilityRevenuesSoldAmount
dei:LegalEntity
us-gaap:AccountsPayableRelatedPartiesCurrent

us-gaap:AccountsReceivableGrossCurrent
dei:LegalEntity
dei:LegalEntity, us-gaap:PublicUtility
us-gaap:AccrualForEnvironmentalLossContingencies
us-gaap:PublicUtility

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent
dei:LegalEntity
dei:LegalEntity, us-gaap:RegulatoryLiability
us-gaap:AmountOfRegulatoryCostsNotYetApproved
us-gaap:LiabilityForCatastropheClaimsByCatastrophicEvent

us-gaap:AssetRetirementObligation
dei:LegalEntity
dei:LegalEntity, us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanType
us-gaap:AssetsFairValueDisclosure
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
dei:LegalEntity
us-gaap:CapitalLeaseObligationsNoncurrent

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
dei:LegalEntity

us-gaap:CommercialPaper
dei:LegalEntity
us-gaap:ConsolidatedEntities

us-gaap:CommonStockHeldInTrust
us-gaap:ConsolidatedEntities

us-gaap:DebtInstrumentCarryingAmount

us-gaap:DebtInstrumentUnamortizedDiscountPremiumNet
dei:LegalEntity

us-gaap:DeferredCosts
dei:LegalEntity

us-gaap:DeferredCreditsAndOtherLiabilities
dei:LegalEntity

us-gaap:DeferredFinanceCostsNet
dei:LegalEntity

us-gaap:DeferredIncomeTaxLiabilities
dei:LegalEntity
dei:LegalEntity, us-gaap:LiabilityForCatastropheClaimsByCatastrophicEvent
us-gaap:DeferredStormAndPropertyReserveDeficiencyNoncurrent
dei:LegalEntity, us-gaap:RegulatoryLiability
dei:LegalEntity, us-gaap:StatementScenario, us-gaap:LiabilityForCatastropheClaimsByCatastrophicEvent
dei:LegalEntity, us-gaap:StatementScenario, us-gaap:RegulatoryLiability

us-gaap:DeferredTaxAssetsGross
dei:LegalEntity

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsDomestic
dei:LegalEntity

us-gaap:DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal
dei:LegalEntity

us-gaap:DeferredTaxAssetsOther
dei:LegalEntity

us-gaap:DeferredTaxAssetsTaxCreditCarryforwards
dei:LegalEntity
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:DeferredTaxLiabilitiesInvestmentInNoncontrolledAffiliates

us-gaap:DeferredTaxLiabilitiesOther
dei:LegalEntity

us-gaap:DeferredTaxLiabilitiesPropertyPlantAndEquipment
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedBenefitObligation
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmountsRecognizedInBalanceSheet
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
us-gaap:Range, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationWeightedAverageInterestCreditingRate
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanBenefitObligation
us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:StatementScenario, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
us-gaap:StatementScenario, us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanFundedStatusOfPlan
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets
us-gaap:RetirementPlanType
us-gaap:Range, us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanWeightedAverageAssetAllocations
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeAssets
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementBasis
us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementBasis
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeAssetsCurrent
us-gaap:DerivativeInstrumentRisk
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeAssetsNoncurrent
us-gaap:DerivativeInstrumentRisk
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeLiabilities
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementBasis
us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByMeasurementBasis
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeLiabilitiesCurrent
us-gaap:DerivativeInstrumentRisk
dei:LegalEntity, us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeLiabilitiesNoncurrent
us-gaap:DerivativeInstrumentRisk
dei:LegalEntity, us-gaap:Energy, us-gaap:TradingActivityByType
us-gaap:DerivativeNonmonetaryNotionalAmount
us-gaap:Energy, us-gaap:TradingActivityByType

us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
dei:LegalEntity

us-gaap:EnergyRelatedInventoryGasStoredUnderground
dei:LegalEntity

us-gaap:EnergyRelatedInventoryOtherFossilFuel
dei:LegalEntity
dei:LegalEntity
us-gaap:EquityMethodInvestmentOwnershipPercentage
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName

us-gaap:EquityMethodInvestments
us-gaap:PublicUtilityRegulatedOrUnregulatedStatus
us-gaap:ScheduleOfEquityMethodInvestmentEquityMethodInvesteeName
us-gaap:StatementBusinessSegments
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerSharePlannedSaleInvestmentsNotIdentifiedValue
us-gaap:RetirementPlanType
dei:LegalEntity, us-gaap:Energy, us-gaap:FairValueByAssetClass
us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
dei:LegalEntity, us-gaap:FairValueByAssetClass
us-gaap:Energy, us-gaap:FairValueByAssetClass
us-gaap:FairValueByAssetClass
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiability
dei:LegalEntity
us-gaap:FinanceLeaseLiabilityNoncurrent
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiabilityPaymentsDue
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiabilityPaymentsDueNextTwelveMonths
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiabilityPaymentsDueYearFive
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiabilityPaymentsDueYearFour
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiabilityPaymentsDueYearThree
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiabilityPaymentsDueYearTwo
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseLiabilityUndiscountedExcessAmount
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:FinanceLeaseRightOfUseAsset
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType
us-gaap:FinancingReceivableRecordedInvestmentPastDue
us-gaap:GuaranteeObligationsByNature
us-gaap:GuaranteeObligationsMaximumExposure
us-gaap:Ownership
dei:LegalEntity
us-gaap:IncomeTaxReceivable
dei:LegalEntity
us-gaap:InterestPayableCurrent

us-gaap:JointlyOwnedUtilityPlantGrossOwnershipAmountOfPlantInService
dei:LegalEntity
dei:LegalEntity, us-gaap:JointlyOwnedUtilityPlant

us-gaap:JointlyOwnedUtilityPlantOwnershipAmountOfConstructionWorkInProgress
dei:LegalEntity
dei:LegalEntity, us-gaap:JointlyOwnedUtilityPlant

us-gaap:JointlyOwnedUtilityPlantOwnershipAmountOfPlantAccumulatedDepreciation
dei:LegalEntity
dei:LegalEntity, us-gaap:JointlyOwnedUtilityPlant
dei:LegalEntity, us-gaap:JointlyOwnedUtilityPlant
us-gaap:JointlyOwnedUtilityPlantProportionateOwnershipShare

us-gaap:LesseeOperatingLeaseDiscountRate
dei:LegalEntity
dei:LegalEntity
us-gaap:LineOfCreditFacilityCurrentBorrowingCapacity

us-gaap:LineOfCreditFacilityRemainingBorrowingCapacity
dei:LegalEntity

us-gaap:LongTermDebtFairValue
dei:LegalEntity
dei:LegalEntity, us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths
dei:LegalEntity

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive
dei:LegalEntity

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour
dei:LegalEntity

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree
dei:LegalEntity

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo
dei:LegalEntity

us-gaap:MoneyMarketFundsAtCarryingValue
dei:LegalEntity
dei:LegalEntity, us-gaap:FairValueByFairValueHierarchyLevel
dei:LegalEntity, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByMeasurementBasis
us-gaap:ConsolidatedEntities
us-gaap:NotesPayableRelatedPartiesClassifiedCurrent
dei:LegalEntity, us-gaap:AccountsNotesLoansAndFinancingReceivableByReceivableType, us-gaap:FinancingReceivablesPeriodPastDue
us-gaap:NotesReceivableGross
us-gaap:ConsolidatedEntities
us-gaap:NotesReceivableRelatedPartiesCurrent
us-gaap:Ownership
us-gaap:OffBalanceSheetCreditLossLiability
dei:LegalEntity, us-gaap:IncomeTaxAuthority
us-gaap:OperatingLossCarryforwards
us-gaap:IncomeTaxAuthority

us-gaap:OtherLongTermInvestments
us-gaap:ConsolidatedEntities

us-gaap:OtherReceivables
dei:LegalEntity
dei:LegalEntity, us-gaap:RetirementPlanType
us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities
us-gaap:RetirementPlanType
dei:LegalEntity, lnt:RedeemablePreferredStockByDividendRate, us-gaap:StatementClassOfStock
us-gaap:PreferredStockValue

us-gaap:PrepaidTaxes
dei:LegalEntity

us-gaap:PropertyPlantAndEquipmentOther

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation
dei:LegalEntity

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress
dei:LegalEntity

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentNet
dei:LegalEntity

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentOtherPropertyPlantAndEquipment
dei:LegalEntity
dei:LegalEntity, us-gaap:PublicUtility
us-gaap:PublicUtilitiesPropertyPlantAndEquipmentPlantInService
us-gaap:PublicUtility

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentPresentValueOfRegulatedAssetForPlantAbandonment
dei:LegalEntity
dei:LegalEntity, us-gaap:PropertyPlantAndEquipmentByType

us-gaap:PurchaseObligation
dei:LegalEntity
dei:LegalEntity, us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

us-gaap:PurchaseObligationDueAfterFifthYear
dei:LegalEntity
dei:LegalEntity, us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

us-gaap:PurchaseObligationDueInFifthYear
dei:LegalEntity
dei:LegalEntity, us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

us-gaap:PurchaseObligationDueInFourthYear
dei:LegalEntity
dei:LegalEntity, us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

us-gaap:PurchaseObligationDueInNextTwelveMonths
dei:LegalEntity
dei:LegalEntity, us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

us-gaap:PurchaseObligationDueInSecondYear
dei:LegalEntity
dei:LegalEntity, us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

us-gaap:PurchaseObligationDueInThirdYear
dei:LegalEntity
dei:LegalEntity, us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased
us-gaap:LongTermPurchaseCommitmentByCategoryOfItemPurchased

us-gaap:RegulatoryAssets

us-gaap:RegulatoryAssetsCurrent
dei:LegalEntity

us-gaap:RegulatoryAssetsNoncurrent
dei:LegalEntity

us-gaap:RegulatoryLiabilities
dei:LegalEntity
dei:LegalEntity, us-gaap:RegulatoryLiability
us-gaap:RegulatoryLiability

us-gaap:RegulatoryLiabilityCurrent
dei:LegalEntity

us-gaap:RegulatoryLiabilityNoncurrent
dei:LegalEntity
dei:LegalEntity, us-gaap:CounterpartyName, us-gaap:RelatedPartyTransactionsByRelatedParty
us-gaap:RelatedPartyTransactionDueFromToRelatedParty
dei:LegalEntity, us-gaap:RelatedPartyTransactionsByRelatedParty
us-gaap:CounterpartyName, us-gaap:RelatedPartyTransaction, us-gaap:RelatedPartyTransactionsByRelatedParty
dei:LegalEntity
us-gaap:RemainingAmountsOfRegulatoryAssetsForWhichNoReturnOnInvestmentDuringRecoveryPeriodIsProvided
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
us-gaap:PlanName
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant

us-gaap:SharePrice
us-gaap:StatementScenario, us-gaap:SubsidiarySaleOfStock
us-gaap:SharesIssuedPricePerShare
us-gaap:SubsidiarySaleOfStock

us-gaap:ShortTermBorrowings
dei:LegalEntity

us-gaap:ShortTermDebtWeightedAverageInterestRate
dei:LegalEntity
dei:LegalEntity, us-gaap:IncomeTaxAuthority
us-gaap:TaxCreditCarryforwardAmount
us-gaap:IncomeTaxAuthority
dei:LegalEntity
us-gaap:TradeReceivablesHeldForSaleAmount
dei:LegalEntity, us-gaap:StatementScenario, us-gaap:SubsequentEventType

us-gaap:UnbilledReceivablesCurrent
dei:LegalEntity
dei:LegalEntity, us-gaap:ValuationAllowancesAndReservesType
us-gaap:ValuationAllowancesAndReservesBalance
us-gaap:ValuationAllowancesAndReservesType

us-gaap:WeightedAverageRateDomesticDepositMoneyMarket
dei:LegalEntity

Plots across concepts


IncomeStatement
Other Comprehensive Income Loss Net Of Tax
Expenses
Income Tax Expense Benefit
Balance Sheet
Cash And Cash Equivalents At Carrying Value
Assets
Cash And Cash Equivalents At Carrying Value
Current Assets
Cash And Cash Equivalents At Carrying Value
NonCurrent Assets
Operating Lease Right Of Use Asset
Liabilities
Operating Lease Liability
Current Liabilities
Operating Lease Liability Current
Noncurrent Liabilities
Operating Lease Liability Noncurrent
Stockholders Equity
Accumulated Other Comprehensive Income Loss Net Of Tax
Per Share
Earnings Per Share Diluted
CashFlow
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInOperatingActivities
Net Cash Provided By Used In Operating Activities
NetCashProvidedByUsedInInvestingActivities
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInFinancingActivities
Proceeds From Payments For Other Financing Activities
Shares
Weighted Average Number Of Shares Outstanding Basic
OperatingLeaseLiability
Operating Lease Liability Current
NonoperatingIncomeExpense
Nonoperating Income Expense
LesseeOperatingLeaseLiabilityPaymentsDue
Lessee Operating Lease Liability Payments Due Next Twelve Months
AccountsReceivable
Allowance For Doubtful Accounts Receivable Current

Tables

  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:CommonStockValue ██▄▄▆▆▆▆▆▆▆▆▅▅▅▅▅▅▅▅▅▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁3.03.02.02.02.52.52.52.42.42.42.42.42.32.32.32.32.32.32.32.32.31.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.1NANANA
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding █▁250.6250.4NA250.0249.8244.6NA239.9238.1236.6NA235.2232.0231.4NANANANANANANANANANANANANANANANANA110.785110.78110.776NA110.779110.769110.741NA110.695110.677110.632NA110.544110.49110.451
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic █▁250.2250.0NA249.7249.6244.4NA239.1237.5236.5NA235.2232.0231.4NANANANANANANANANANANANANANANANANA110.783110.776110.767NA110.768110.756110.716NA110.647110.624110.569NA110.469110.409110.368
us-gaap:EarningsPerShareBasic NANA0.250.99NANA0.459999999999999960.95NANA0.35999999999999990.87NANANANANANANANANANANANANANANANANANANANANANANANANANA0.51000000000000021.10.460.660.430000000000000161.350.430.39
us-gaap:EarningsPerShareDiluted NANA0.250.98NANA0.460.940.40.530.360.870.430.520.410.730.410.440.280.570.370.430.31.590.60.870.541.380.560.970.591.420.590.630.621.360.60.320.511.10.460.660.431.350.430.39
us-gaap:EarningsPerShareBasicAndDiluted NA0.68NANA0.540.7NANA0.40.530.35999999999999990.870.430.520.39999999999999990.730.410.440.27999999999999980.570.370.850.29999999999999981.590.60.870.541.380.560.970.58999999999999991.420.590.630.62000000000000011.360.60.320.51000000000000021.10.460.66NANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 COGS Ratio dei:LegalEntity lnt:Ipl▂▃▁▆▁▅▄█▁▆▄▆▃455.0489.0443.0553.0431.9518.9496.8596.5441.2555.1494.1547.6474.8NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 COGS Ratio dei:LegalEntity lnt:Wpl▃▇▄▄▁▅▄▅▂█▅▅▂341.0395.0357.0351.0312.3375.2362.3372.1326.1415.2369.4370.7330.8NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 Cost Ratio dei:LegalEntity lnt:Ipl▄▅▃▇▃▆▅█▃▇▅▇▄▆▄▆▃▄▃▆▂▄▂▅▂▅▃▄▃▆▄▅▂▄▂▅▁▂▂▅▁▄▃▆▂455.0489.0443.0553.0431.9518.9496.8596.5441.2555.1494.1547.6474.8525.8472.2527.4420.2450.5434.5516.2411.0458.7398.7504.6382.2489.0431.1476.2411.9528.9463.1494.4383.4477.9393.2497.7360.7398.7404.0484.5374.1477.5417.2534.8389.3NA
 Cost Ratio dei:LegalEntity lnt:Wpl▃▇▄▄▁▅▄▅▂█▅▅▂▆▅▅▃▆▄▇▂▅▂▆▂▇▄▄▂█▄▄▂▅▃▅▁▄▃▅▂▆▃▅▁341.0395.0357.0351.0312.3375.2362.3372.1326.1415.2369.4370.7330.8381.7374.7370.2334.8393.1352.2397.0334.3375.6330.7382.6324.7397.1359.8354.4324.5410.4355.7360.9319.9369.8345.2376.6315.7354.5344.5374.6326.8388.5348.2369.6312.9NA
 EBT Margin dei:LegalEntity lnt:Ipl▄▅▃▇▃▆▅█▃▇▅▇▄▆▄▆▃▄▃▆▂▄▂▅▂▅▃▄▃▆▄▅▂▄▂▅▁▂▂▅▁▄▃▆455.0489.0443.0553.0431.9518.9496.8596.5441.2555.1494.1547.6474.8525.8472.2527.4420.2450.5434.5516.2411.0458.7398.7504.6382.2489.0431.1476.2411.9528.9463.1494.4383.4477.9393.2497.7360.7398.7404.0484.5374.1477.5417.2534.8NANA
 EBT Margin dei:LegalEntity lnt:Wpl▃▇▄▄▁▅▄▅▂█▅▅▂▆▅▅▃▆▄▇▂▅▂▆▂▇▄▄▂█▄▄▂▅▃▅▁▄▃▅▂▆▃▅341.0395.0357.0351.0312.3375.2362.3372.1326.1415.2369.4370.7330.8381.7374.7370.2334.8393.1352.2397.0334.3375.6330.7382.6324.7397.1359.8354.4324.5410.4355.7360.9319.9369.8345.2376.6315.7354.5344.5374.6326.8388.5348.2369.6NANA
 Operating Margin dei:LegalEntity lnt:Ipl▄▅▃▇▃▆▅█▃▇▅▇▄▆▄▆▃▄▃▆▂▄▂▅▂▅▃▄▃▆▄▅▂▄▂▅▁▂▂▅▁▄▃▆▂▄455.0489.0443.0553.0431.9518.9496.8596.5441.2555.1494.1547.6474.8525.8472.2527.4420.2450.5434.5516.2411.0458.7398.7504.6382.2489.0431.1476.2411.9528.9463.1494.4383.4477.9393.2497.7360.7398.7404.0484.5374.1477.5417.2534.8389.3454.5
 Operating Margin dei:LegalEntity lnt:Wpl▃▇▄▄▁▅▄▅▂█▅▅▂▆▅▅▃▆▄▇▂▅▂▆▂▇▄▄▂█▄▄▂▅▃▅▁▄▃▅▂▆▃▅▁▆341.0395.0357.0351.0312.3375.2362.3372.1326.1415.2369.4370.7330.8381.7374.7370.2334.8393.1352.2397.0334.3375.6330.7382.6324.7397.1359.8354.4324.5410.4355.7360.9319.9369.8345.2376.6315.7354.5344.5374.6326.8388.5348.2369.6312.9392.9
 Operating Margin dei:LegalEntity,us-gaap:StatementBusinessSegments lnt:Ipl,lnt:Electric▄▃▃▇▃▄▄█▄▄▄▇▄▄▃▆▃▃▃▆▃▃▂▆▂▃▂▅▃▃▃▅▂▂▁▅▂▁▁▅▂▂▂▆402.0386.0363.0519.0388.4424.8408.0560.9392.3419.8394.1509.2422.1405.7381.3489.0372.4356.2360.5483.2364.4361.6333.2468.6339.4362.6328.6435.9354.6374.2354.4457.6329.6350.2300.4456.6321.0293.1311.0443.2323.9330.2317.5492.4NANA
 Operating Margin dei:LegalEntity,us-gaap:StatementBusinessSegments lnt:Ipl,lnt:Gas▂▅▄▁▂▅▄▁▂▇▅▁▂▆▄▁▂▅▃▁▂▅▃▁▁▆▅▁▂█▅▁▂▇▄▁▁▅▄▁▂█▅▁43.091.067.024.033.983.076.224.838.4124.689.226.742.2108.178.827.436.783.161.423.934.584.253.223.129.8111.288.428.743.7135.793.024.642.0114.377.529.626.892.878.227.538.7131.986.428.1NANA
 Operating Margin dei:LegalEntity,us-gaap:StatementBusinessSegments lnt:Ipl,lnt:OtherUtility▂▃▄▂▁▂▃▂▂▂▂▃▂▃▃▂▂▂▃▁▃▄▃▄▄▅▅▃▄█▆▃▃▄▅▃▄▄▅▄▃▅10.012.013.010.09.611.112.210.810.510.710.811.710.512.012.111.011.111.212.69.112.112.912.312.913.015.214.111.613.619.015.712.211.813.415.311.512.912.814.813.811.515.4NANANANA
 Operating Margin dei:LegalEntity,us-gaap:StatementBusinessSegments lnt:Wpl,lnt:Electric▃▃▂▅▂▃▃▆▂▄▃▆▃▃▃▆▃▄▃█▃▃▂▇▂▃▂▅▂▃▂▅▁▁▂▆▂▁▂▆▂▂▁▆315.0315.0300.0333.0286.8305.5305.5355.0298.9323.6310.0352.0304.2303.0314.3351.6308.5321.4305.9381.1311.5307.3289.8367.2301.0308.7294.1335.3289.3301.6291.2340.5282.5283.0288.6358.7291.6279.3287.1353.7296.6290.1282.5349.6NANA
 Operating Margin dei:LegalEntity,us-gaap:StatementBusinessSegments lnt:Wpl,lnt:Gas▂▆▄▁▂▅▄▁▂▇▄▁▂▆▄▁▂▅▃▁▂▅▃▁▂▇▅▁▂█▅▁▂▆▄▁▂▆▄▁▂▇▅▁26.079.053.018.025.069.256.316.726.891.258.418.126.477.559.418.425.971.245.315.622.568.039.914.921.987.264.318.533.2105.061.315.231.483.054.917.223.274.356.018.928.497.163.318.4NANA
 Operating Margin us-gaap:PublicUtilityRegulatedOrUnregulatedStatus,us-gaap:StatementBusinessSegments us-gaap:UnregulatedOperation,us-gaap:AllOtherSegments█▁21.017.0NA16.018.921.6NA21.622.916.9NA10.310.58.8NA9.310.310.3NA11.49.39.5NA11.710.311.3NA12.513.913.5NA11.314.711.9NA13.313.912.5NANANA11.2NANANANA
 Operating Margin us-gaap:StatementBusinessSegments lnt:Electric▄▄▃▇▃▄▄█▃▄▄▇▄▄▄▆▃▃▃▇▃▃▂▆▂▃▂▅▂▃▂▆▂▂▁▆▂▁▂▆717.0701.0663.0852.0675.2730.3713.5915.9691.2743.4704.1861.2726.3708.7695.6840.6680.9677.6666.4864.3675.9668.9623.0835.8640.4671.3622.7771.2643.9675.8645.6798.1612.1633.2589.0815.3612.6572.4598.1796.9NA620.3600.0842.0NANA
 Operating Margin us-gaap:StatementBusinessSegments lnt:Gas▂▆▄▁▂▅▄▁▂▇▅▁▂▆▄▁▂▅▃▁▂▅▃▁▁▇▅▁▂█▅▁▂▇▄▁▁▅▄▁69.0170.0120.042.058.9152.2132.541.565.2215.8147.644.868.6185.6138.245.862.6154.3106.739.557.0152.293.138.051.7198.4152.747.276.9240.7154.339.873.4197.3132.446.850.0167.1134.246.4NA229.0149.746.5NANA
 Operating Margin us-gaap:StatementBusinessSegments lnt:OtherUtility▁▃▅▁▁▂▃▂▂▂▂▃▂▃▃▂▂▂▃▁▃▃▃▃▄▅▄▂▄█▆▅▅▅▅▂▃▃▅▄10.013.017.010.010.111.613.311.210.911.111.812.310.713.213.111.211.511.713.69.412.413.213.313.414.816.415.512.215.622.818.917.417.817.217.012.213.813.716.215.8NA16.715.715.9NANA
 Operating Margin us-gaap:StatementBusinessSegments lnt:UtilityBusiness▄▆▄▆▃▆▅█▃█▅▇▄▇▅▆▃▅▄▇▃▅▂▆▂▆▄▅▂▇▄▅▂▅▂▆▁▃▃▅796.0884.0800.0904.0744.2894.1859.1968.6767.3970.3863.5918.3805.6907.5846.9897.6755.0843.6786.7913.2745.3834.3729.4887.2706.9886.1790.9830.6736.4939.3818.8855.3703.3847.7738.4874.3676.4753.2748.5859.1NA866.0765.4904.4NANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 TTM Greenblatt ROC _ _▄▅▂▇▄▅▄█▃▄▃▇▄▄▃▆▃▃▂▄▃▃▁▆▂▄▂▅▂▄▂▅▂▃▂▆▂▂▂▅▁▃▂176.0198.0112.0272.0168.1188.3160.9290.2149.8176.8121.4256.1151.2165.7129.7231.5149.3142.999.9162.6128.6145.979.2235.9109.0152.991.3194.8103.3154.2108.6201.4103.2120.7101.6213.7108.895.693.5185.172.0127.899.8NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AllocatedShareBasedCompensationExpense ▂▃▅▄▃▃█▆▃▄▄▄▄▃▄▄▂▃▂▄▆▅▄▁▂▃▆▂▃▃▃▄▂▃▃▁▂▂▄▁▃▂▂▃▂2.03.06.05.02.72.710.47.53.44.74.44.25.13.35.25.11.63.21.24.47.15.34.90.32.33.27.91.23.13.13.44.01.92.73.10.12.11.65.20.12.62.21.32.61.3NA
us-gaap:CostOfGoodsAndServicesSold ▇█▇█▁▇▆▇▆▇▆▇▆121.0134.0123.0132.071.6122.2118.5127.5112.4123.0120.5129.1119.7NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:CostsAndExpenses ▃▄▄▃▁▅▅▄▃▇▆▃▃▆▅▄▂▅▄▆▂▄▃▃▂▅▅▃▃▇▅▃▂▅▃▄▁▃▇█▆▇▅▄▃▆641.0703.0705.0648.0595.0727.4719.2700.0640.4810.4752.1672.5664.9750.6726.4675.4616.0711.0697.1762.0626.0697.9660.9663.0608.2744.5712.8648.3647.0798.6724.0665.2614.8738.9649.3673.9581.5670.1785.7836.5747.5817.2732.8705.1640.9781.2
us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest ▄▄▁▇▄▅▄█▃▄▃▇▃▄▃▆▄▄▂▄▃▄▁▇▂▄▂▅▂▄▂▆▂▃▂▆▂▂▂▅▁▃▂▇129.0146.056.0229.0128.6153.9133.3251.7108.3142.893.4219.8116.5140.398.1197.5118.0119.277.7138.9105.0121.848.6210.482.6119.760.8170.277.8131.282.8179.178.995.280.7192.386.271.070.0160.043.3100.675.1219.6NANA
us-gaap:IncomeTaxExpenseBenefit ▂▁▂▂▂▂▅▅▄▄▄▄▄▄▃▅▅▄▄▄▅▅▄▅▄▅▃▄▄▅▄▄▄▄▄▆▄▅▄▆▂▅▅█▅▆-17.0-28.0-10.0-20.0-8.3-18.719.323.111.215.15.611.713.616.81.826.121.217.612.27.518.121.610.927.811.220.5-1.912.413.220.613.717.610.512.15.639.316.827.79.034.1-10.622.623.464.123.034.7
 us-gaap:IncomeTaxExpenseBenefit dei:LegalEntity lnt:Ipl▃▃▃▂▄▂▆▅▄▄▄▃▄▄▅▂▄▄▄▄▄▄▄▂▄▄▂▁▄▃▄▁▃▃▃▃▄▅▄▄▄▄▃█▅-10.0-12.0-10.0-19.0-3.8-14.113.26.91.92.1-2.7-5.92.33.17.7-14.3-0.6-3.7-3.4-2.50.8-0.83.1-19.6-2.6-3.6-16.8-26.5-3.4-5.0-0.5-26.4-4.9-6.1-13.2-11.9-2.17.4-1.4-3.2-0.71.7-8.435.05.8NA
 us-gaap:IncomeTaxExpenseBenefit dei:LegalEntity lnt:Wpl▃▁▃▃▃▂▅▆▅▅▅▅▄▅▄▇▆▆▆█▆▇▅█▆▆▆▇▆▇▇▇▆▆▆█▆▇▆▇▅▆▇▇▆-7.0-19.0-2.0-5.0-4.5-8.29.917.17.714.68.110.26.211.71.823.016.720.416.233.720.822.68.933.118.822.117.623.917.826.322.527.217.020.519.131.219.125.222.326.911.321.427.329.816.2NA
us-gaap:IncomeTaxesPaidNet NANA1.0-11.04.90.1-19.71.74.3-6.80.00.05.00.0-0.10.09.12.31.54.04.30.00.00.10.0-0.10.0-1.50.1-3.90.10.0-12.02.3-19.50.1-0.8-0.1-7.80.00.0-3.0-109.80.3-5.9-0.8
 us-gaap:IncomeTaxesPaidNet dei:LegalEntity lnt:WplNANA-8.0-3.9NANA21.90.5NANA-25.23.3NANA-11.80.919.30.0-8.2-16.6-10.47.4-2.66.312.8-9.13.5-0.710.0-0.623.5-9.1-17.425.9-11.2-7.93.612.2-14.2-1.3-2.6-33.2-17.7-7.8NANA
us-gaap:InterestExpense █████████▇▇▇▆▆▅▄▄▄▄▃▃▃▃▃▃▃▃▂▃▃▃▂▂▂▂▁▁▁▁▁▁▂▂▂▁▂69.069.068.068.069.668.969.168.369.266.363.263.361.359.256.653.952.852.351.448.848.048.047.646.446.546.645.744.645.145.245.242.542.542.640.938.338.638.938.638.740.440.640.841.939.640.7
us-gaap:InterestPaidNet █▅█▅▇▆▇▅▇▆█▄▆▄▄▄▄▄▄▃▄▃▄▂▄▂▃▂▃▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▃78.059.077.058.973.264.973.262.069.862.975.951.865.654.254.153.553.251.851.744.951.344.550.940.453.340.249.041.349.141.443.241.843.243.539.638.238.638.838.638.840.040.240.142.935.147.4
us-gaap:NetIncomeLoss ▅▆▂█▄▅▄▇▃▄▃▇▃▄▃▅▃▃▂▄▃▃▁▆▂▃▂▅▂▃▂▅▂▂▂▅▂▁▂▄▂▂▂▅▂▁146.0174.066.0249.0136.9172.6114.0228.697.1127.787.8208.1102.9123.596.3171.496.8103.065.2131.086.499.136.6182.570.199.262.5155.964.3110.668.1160.267.880.172.3154.769.838.961.0125.955.379.752.0153.752.548.1
us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic ▅▆▂█▄▅▄▇▃▄▃▇▃▄▃▅▃▃▂▄▃▃▁▆▂▃▂▅▂▃▂▅▂▂▂▅▂▁▂▄▂▂▁▅▁▁144.0171.064.0246.0134.4170.0111.5226.094.6125.185.3205.5100.4120.993.8168.894.3100.462.7128.483.996.534.1179.967.696.660.0153.361.8108.065.5157.665.369.968.3150.765.934.957.0122.051.173.547.3149.147.843.4
us-gaap:NonoperatingIncomeExpense ▃▂▁▄▄▅▇▄▄▅▇▅▅▇▆▅▆▇█▇▇▇▆▇▇▆▆▇▇█▇█▇▇███▇▇▇▇▇▇▇▇▇-47.0-52.0-56.0-43.0-39.5-34.4-27.6-38.5-41.5-34.0-28.0-36.3-34.7-25.4-31.6-34.0-31.3-23.7-22.2-23.7-23.6-24.1-30.6-25.5-26.4-33.2-30.5-24.6-25.5-23.0-25.8-22.3-24.3-25.5-20.9-21.4-22.6-24.6-23.5-25.1-27.3-26.8-24.7-27.0-25.0-26.2
 us-gaap:NonoperatingIncomeExpense dei:LegalEntity lnt:Ipl▂▂▁▃▃▄▅▅▄▇▇▆▅▅▅▅▅████▇▇▇▆▆▆▇▇▇▇▇▇▇▇▆▆▆▆▆▆▆▆▆▆-33.0-33.0-37.0-30.0-30.2-25.6-20.9-22.9-25.1-15.5-15.5-19.9-21.2-23.2-22.6-23.1-21.6-13.5-11.8-11.7-12.8-14.6-15.9-16.6-17.2-18.7-18.0-15.3-16.5-16.5-15.6-13.8-14.9-15.7-16.6-17.4-17.9-18.0-17.9-18.3-18.2-18.3-19.2-20.1-18.2NA
 us-gaap:NonoperatingIncomeExpense dei:LegalEntity lnt:Wpl▁▁▁▂▃▅▅▄▄▄▄▄▄▃▄▄▃▃▆▆▆▇▅▇▆▅▆▇▇█▇▇▇▇███▇▇▇▇▇▇▇█-24.0-25.0-24.0-21.0-18.6-12.4-14.1-15.7-17.3-17.8-15.2-17.7-17.4-18.3-17.8-17.9-18.9-20.1-9.5-11.7-10.5-9.2-15.0-9.3-10.0-13.9-12.0-8.4-7.6-6.6-7.1-7.4-8.3-8.6-5.2-5.5-6.3-7.5-8.2-8.6-9.2-9.0-7.7-6.9-5.9NA
us-gaap:OperatingIncomeLoss ▄▅▂▇▄▅▄█▃▄▃▇▄▄▃▆▃▃▂▄▃▃▁▆▂▄▂▅▂▄▂▅▂▃▂▆▂▂▂▅▁▃▂▇▂▂176.0198.0112.0272.0168.1188.3160.9290.2149.8176.8121.4256.1151.2165.7129.7231.5149.3142.999.9162.6128.6145.979.2235.9109.0152.991.3194.8103.3154.2108.6201.4103.2120.7101.6213.7108.895.693.5185.172.0127.899.8246.6100.7109.0
us-gaap:OtherComprehensiveIncomeLossNetOfTax NANA0.0-0.1-2.60.70.30.0-1.40.71.9-0.30.60.0-0.10.00.00.00.00.00.00.00.20.00.00.0-0.40.00.00.00.60.0NANANANANANANANANANANANANANA
 us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents us-gaap:AccumulatedOtherComprehensiveIncomeNANA0.0-0.1-2.60.70.30.0-1.40.71.9-0.30.6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherNonoperatingIncomeExpense ▄▄▁▄▄▅▃▃▄▃▅▅▄▄▆▆▆▆▆▆▆▆▆▆▆▆▆▆▆▇▅▆▆▆▇▆▆▇▇▆▆▆█▆▆▆-2.0-2.0-7.0-3.0-2.5-1.9-3.4-3.7-3.3-4.0-1.6-1.6-2.0-2.40.10.20.10.10.20.10.00.20.30.10.20.10.00.2-0.11.7-1.30.60.30.81.60.70.61.12.00.70.80.83.10.6-0.50.8
 us-gaap:OtherNonoperatingIncomeExpense dei:LegalEntity lnt:Ipl-2.0NA-5.0-1.0-1.0-0.9-1.5-2.0-1.5-1.9-0.6-0.5-0.7-0.80.00.10.2-0.10.20.00.10.00.2-0.10.00.1-2.40.00.10.00.10.00.10.10.00.00.00.20.1-0.10.00.20.30.2-0.3NA
 us-gaap:OtherNonoperatingIncomeExpense dei:LegalEntity lnt:Wpl▆▃▆▃▃▄▂▂▁▁▁▂▃▃▅▆▆▆▆▅▆▆▆▆▆▅█▄▅▆▆▆▅▆0.0-1.00.0-1.0-0.8-0.5-1.4-1.4-1.6-1.6-1.7-1.3-1.0-1.1-0.10.10.00.10.0-0.10.20.10.10.30.1-0.10.9-0.5-0.30.00.10.0-0.10.1NANA-0.10.1NANA0.0NANA-0.10.1NA
us-gaap:RegulatedAndUnregulatedOperatingRevenue ▄▅▄▆▃▆▅▇▃▇▅▆▄▆▅▆▃▄▃▆▂▄▂▅▂▅▃▄▂▇▄▅▂▅▂▅▁▃▅█▄▆▄▇▂▅817.0901.0817.0920.0763.1915.7880.1990.2790.2987.2873.5928.6816.1916.3856.1906.9765.3853.9797.0924.6754.6843.8740.1898.9717.2897.4804.1843.1750.3952.8832.6866.6718.0859.6750.9887.6690.3765.7879.21021.6819.5945.0832.6951.7741.6890.2
us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax ▄▅▄▆▃▆▅▇▃▇▅▆▄▆▅▆▃▄▃▆▂▄▂▅▂▅▃▄▂▇▄▅▂▅▂▅▁▃▅█▄▆▄▇▂▅817.0901.0817.0920.0763.1915.7880.1990.2790.2987.2873.5928.6816.1916.3856.1906.9765.3853.9797.0924.6754.6843.8740.1898.9717.2897.4804.1843.1750.3952.8832.6866.6718.0859.6750.9887.6690.3765.7879.21021.6819.5945.0832.6951.7741.6890.2
us-gaap:Revenues ▄▅▄▆▃▆▅▇▃▇▅▆▄▆▅▆▃▄▃▆▂▄▂▅▂▅▃▄▂▇▄▅▂▅▂▅▁▃▅█▄▆▄▇▂▅817.0901.0817.0920.0763.1915.7880.1990.2790.2987.2873.5928.6816.1916.3856.1906.9765.3853.9797.0924.6754.6843.8740.1898.9717.2897.4804.1843.1750.3952.8832.6866.6718.0859.6750.9887.6690.3765.7879.21021.6819.5945.0832.6951.7741.6890.2
us-gaap:UnregulatedOperatingRevenue ▂▁▁▁▁▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▇█▆▄▄▃▂▃21.017.017.016.018.921.621.021.622.916.910.010.310.58.89.29.310.310.310.311.49.39.510.711.710.311.313.212.513.913.513.811.314.711.912.513.313.912.5130.7162.5118.679.067.247.339.442.8
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:Assets ████▇▇▇▇▇▆▆▆▅▅▅▅▅▄▄▄▄▄▄▄▃▃▃▃▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁17939.017594.017710.017540.017269.716879.016700.716533.416121.615713.415426.015269.814615.014241.814187.814114.913743.413464.913373.813029.212685.412535.012495.212558.612312.312079.612085.911594.011386.611116.811112.410981.210887.610733.910785.510250.99934.29628.29687.99481.39301.29400.59282.9NANANA
us-gaap:LiabilitiesAndStockholdersEquity ████▇▇▇▇▇▆▆▆▅▅▅▅▅▄▄▄▄▄▄▄▃▃▃▃▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁17939.017594.017710.017540.017269.716879.016700.716533.416121.615713.415426.015269.814615.014241.814187.814114.913743.413464.913373.813029.212685.412535.012495.212558.612312.312079.612085.911594.011386.611116.811112.410981.210887.610733.910785.510250.99934.29628.29687.99481.39301.29400.59282.9NANANA
us-gaap:StockholdersEquity ████▇▇▇▆▅▅▅▅▄▄▄▄▄▃▃▃▃▃▃▃▃▃▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁5819.05766.05688.05709.05548.35502.45205.14969.24699.64682.44585.74570.44350.74231.54182.24154.24050.43896.93862.03859.13790.23764.63724.13745.23620.83597.13438.73435.63337.43331.53281.43266.73160.53145.93134.93116.03014.42997.53013.03001.62927.22920.52893.6NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AssetsCurrent ▄▂▄▆▇▄▄█▆▃▂█▃▁▄▂▃▂▄▅▁▂▃▇▇▄▇▅▆▅▆▄▄▄▆▆▅▂▄▅▄▆▇899.0755.0887.01033.01044.3912.2875.51113.01027.3815.2785.11124.8805.9725.9905.1751.5814.7749.8877.1958.1702.3768.5826.81087.71043.9913.21043.1962.31010.1936.21011.2880.1893.4870.4994.31028.6920.4780.6866.5947.1877.8977.01092.7NANANA
us-gaap:CashAndCashEquivalentsAtCarryingValue ▁▁▂▆▇▃▁▇▆▁▁█▁▁▂▁▁▁▁▃▁▁▁▅▂▄▃▁▁▁▁▁▁▂▁▂▂▂▁▂▃▅▆▅▆▅15.014.054.0189.0208.155.216.3193.7170.210.120.9239.75.019.127.99.27.38.48.284.76.54.85.8139.254.897.656.911.016.214.59.817.711.553.421.241.130.830.911.445.777.1126.1159.3137.0171.1140.2
us-gaap:AccountsReceivableNetCurrent ▆▅▇▆▆▆▆▇▇▇▆█▇▅█▅▇▇██▅▆▆▇▅▆▇▁▁▁▁▁▁▁▁▁▁▁▃▃▂▂▂377.0325.0412.0399.0386.5396.4402.1451.5421.5417.9350.4465.3415.0343.2482.8336.1424.9424.9493.3491.5316.3390.6397.6427.3297.3361.6427.384.385.9106.681.878.185.098.994.993.981.792.2188.8198.5127.8140.2120.5NANANA
us-gaap:InventoryRawMaterialsAndSupplies ██▆▇▆▆▆▆▆▆▆▆▇▇▆▅▅▄▄▄▄▄▄▄▄▄▃▃▃▂▂▂▂▂▂▁▁▁▁▁▁▂▁119.0122.0105.0113.0107.0105.0100.5106.9105.1105.1101.4106.8109.4109.8105.699.194.788.886.689.583.283.381.483.782.381.572.972.975.572.169.671.168.364.963.161.461.161.758.561.161.564.161.6NANANA
us-gaap:OtherAssetsCurrent ▄▂▃▂▃▃▂▃▃▃▂▃▂▂▂▂▂▂▂▂▂▂▂▄█▄▂▆▅▄▂▂▃▃▁▁▁▁▃▃▄▄▂204.0117.0123.0118.0133.4137.5101.7137.1151.1153.480.0126.5113.985.987.7101.4112.470.495.598.998.864.479.7217.4435.5227.6116.9294.4289.7209.784.9119.0125.7157.543.341.734.960.4153.5132.1185.7192.1111.4NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 us-gaap:AssetsNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA6388.0NANANA5964.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:PropertyPlantAndEquipmentNet ████▇▇▇▇▆▆▆▆▅▅▅▅▄▄▄▄▄▄▃▃▃▃▃▃▃▃▂▂▂▂▂▂▁▁▁▁▁▁▁14540.014353.014336.014199.013936.413685.013527.113131.112854.012665.212462.412005.211695.711439.611234.510931.110608.110448.810279.29920.49846.49626.69519.19366.59173.59050.08938.48763.68566.28426.28326.58141.48027.27913.67838.07384.67248.07081.37037.16937.96866.46823.46730.6NANANA
us-gaap:LongTermInvestments ██▇▇▇▇▇▆▆▆▆▅▅▅▄▆▃▃▃▂▂▂▃▃▃▃▃▃▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁506.0494.0485.0478.0473.2469.5467.8453.0443.3433.6431.3424.0420.5414.7396.1458.6354.5346.8337.6329.6324.8323.5346.3353.1349.9343.9344.9343.3338.6332.9329.6324.7321.3321.6319.0314.1308.4303.7300.8299.2296.1292.2289.2NANANA
us-gaap:OperatingLeaseRightOfUseAsset NANA15.0NANANA16.017.017.018.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:OperatingLeaseRightOfUseAsset dei:LegalEntity lnt:IplNANA9.0NANANA10.010.010.010.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:OperatingLeaseRightOfUseAsset dei:LegalEntity lnt:WplNANA6.0NANANA6.07.07.07.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherAssetsNoncurrent ███▇▇▇▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁1994.01992.02002.01830.01815.81812.372.072.668.872.889.7103.386.472.469.721.418.614.922.69.410.910.714.635.738.241.243.955.267.968.685.899.1111.9108.9105.398.176.882.292.193.4121.9130.9137.7NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AccountsPayableCurrent ▄▂▄▅▅▄▅▇▅▄█▇▅▃▆▆▄▄▆▄▃▃▄▅▄▃▅▆▆▄▄▄▄▄▃▅▃▁▂▂▂▂▃392.0307.0377.0417.0429.9375.4422.3497.7422.5387.7543.3498.1431.1363.1477.3478.1381.1369.5445.3365.1353.0323.8402.4438.3374.9356.9427.9471.1475.6388.1365.0368.7391.1368.6339.3418.0337.6263.9308.2314.6305.8300.2336.3NANANA
us-gaap:LiabilitiesCurrent ▅▄▄▄▃▅██▇▅▅▅▄██▅▃▃▃▄▄▄▄▂▂▂▃▆▆▄▄▂▃▂▂▂▂▁▁▁▁▁▂1639.01408.01297.01295.01220.91650.22054.12082.11949.01587.71644.11548.31257.42073.52149.01470.11208.21165.01162.01369.71373.21348.51359.3990.8991.51023.11214.71741.91733.21384.21433.31052.81072.51038.11020.0945.5957.3773.3855.0774.4760.1778.9866.7NANANA
us-gaap:LongTermDebtCurrent ▄▄▁▁▁▄▆▆▇▃▃▅▄██▂▁▁▁▄▄▄▄▁▁▂▂▅▅▄▄▁▁▁▁▁▁▁▁▁▁▁▁308.0308.08.07.07.4357.2657.2656.8706.8256.5256.5506.1356.1855.7855.7105.25.24.64.6314.0314.0313.4313.43.033.5183.0183.0492.8509.0358.8358.548.41.51.51.51.41.41.41.41.41.41.31.3NANANA
us-gaap:OperatingLeaseLiabilityCurrent NANA2.0NANANA2.02.02.03.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherLiabilitiesCurrent ▄▄▃▅▇██▇▅▄▅▄▄▄▅▄▅▅▄▅▅▆▅▄▅▄▅▃▄▃▂▄▄▃▂▁▁▁▂▂▃▃▃230.0249.0207.0286.0386.8407.3425.2389.1262.3249.0260.4255.6247.9251.1260.8217.0265.7272.9222.3273.9284.3304.8296.6250.7264.5232.3262.4204.0215.9191.5133.1223.5244.0196.1113.599.393.487.3127.5152.7161.4163.6160.1NANANA
us-gaap:TaxesPayableCurrent NANA67.0NANANA70.0NANANANANANANANA39.4NANA59.5NANANA53.2NANANANANANANA50.0NANANA48.037.446.339.747.937.845.837.745.3NANANA
 us-gaap:TaxesPayableCurrent dei:LegalEntity lnt:IplNANA54.0NANANA63.358.764.7NA45.8NANANA47.139.3NA37.253.841.2NANA67.6NANANA45.334.5NA37.451.1NANANA46.838.067.248.343.834.257.4NA62.4NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 us-gaap:LiabilitiesNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA2997.0NANANA2659.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LongTermDebt dei:LegalEntity,us-gaap:FairValueByMeasurementBasis lnt:Ipl,us-gaap:CarryingReportedAmountFairValueDisclosure█████▇▇▇▅▄▃▅▃▃▂▁▁▁▁▁3346.03346.03345.03344.03343.53147.93147.33146.82850.52667.82552.32801.82531.82452.22406.02195.02194.52154.02153.52153.1NANA1856.9NANANANA1520.31558.71558.61558.41374.81364.71344.51359.5NANANANANANANANANANANA
 us-gaap:LongTermDebt dei:LegalEntity,us-gaap:FairValueByMeasurementBasis lnt:Wpl,us-gaap:CarryingReportedAmountFairValueDisclosure▇▇▇▇▇▅▅▅█▄▄▄▄▄▄▁▁▁▁▁2131.02131.02130.02130.02129.41933.11932.71932.32181.81835.41834.91834.51834.11833.71833.41536.21535.91535.51535.21534.9NANA1533.9NANANANA1324.01332.31332.21332.11332.01331.91331.71331.5NANANANANANANANANANANA
 us-gaap:LongTermDebt us-gaap:FairValueByMeasurementBasis us-gaap:CarryingReportedAmountFairValueDisclosure███▇▇▆▆▆▆▅▅▅▅▃▃▂▂▂▂▁6776.06779.06777.06581.06579.86191.16190.26191.96144.95618.75502.85754.35483.64912.54866.34360.34359.54320.74320.24130.9NANA3835.6NANANANA3292.33338.93339.43336.33153.23142.93123.43138.1NANANANANANANANANANANA
us-gaap:LongTermDebtNoncurrent ▇▇███▆▆▆▆▆▅▅▅▃▃▄▄▄▄▃▃▂▂▃▃▃▃▁▁▁▁▂▂▂▂▁▁▁▁▁▁▁▁6468.06471.06769.06574.06572.45833.95533.05535.15438.15362.25246.35248.25127.54056.84010.64255.14354.34316.14315.63816.93588.43522.73522.23855.83717.43606.73606.72799.52829.92980.62977.83104.83141.43121.93136.62828.12752.82728.22703.12703.62703.52703.62703.4NANANA
us-gaap:DeferredIncomeTaxLiabilitiesNet █▇▆▅▃▂▁1865.01843.01814.01803.01761.31736.11714.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent ▇██▆▇▇▇▇▇██▇▇██▇▇▇█▇▇▇▇▆▆▆▆▁▁▁▁▅▅▅▅▃▃▃▄▂▂▃▃477.0495.0511.0423.0450.2452.6484.0476.3487.4493.6509.1487.0488.7488.9504.0481.3482.7481.7489.9455.3452.2446.5451.8416.4417.4417.7421.7201.3202.1203.0206.6356.6359.2360.3364.0310.8309.9309.6312.7235.9241.8299.2303.8NANANA
 us-gaap:MinorityInterest us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA192.0NANANA208.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherLiabilitiesNoncurrent ▆▆▆▅▅▅▄▄▇█▃▃▄▄▄▄▃▄▃▄▄▄▄▅▅▃▃▃▂▃▃▃▃▂▃▃▂▂▃▂▁▁▁391.0364.0374.0348.0357.0349.7298.9305.6413.6442.9287.2286.8310.4313.8306.4296.1288.3297.9279.3300.2297.3310.2306.0333.0342.8259.7260.1267.1253.7262.2273.9271.9275.8257.3262.5269.1245.1248.9259.6251.6212.3208.5208.9NANANA
us-gaap:OperatingLeaseLiabilityNoncurrent NANA13.0NANANA14.015.015.015.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:OperatingLeaseLiabilityNoncurrent dei:LegalEntity lnt:IplNANA8.0NANANA9.09.09.09.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:OperatingLeaseLiabilityNoncurrent dei:LegalEntity lnt:WplNANA5.0NANANA5.06.06.06.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive NANA8.0NANANA10.013.013.013.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive dei:LegalEntity lnt:IplNANA6.0NANANA7.09.09.09.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive dei:LegalEntity lnt:WplNANA2.0NANANA3.04.04.03.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:StockholdersEquity ████▇▇▇▆▅▅▅▅▄▄▄▄▄▃▃▃▃▃▃▃▃▃▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁5819.05766.05688.05709.05548.35502.45205.14969.24699.64682.44585.74570.44350.74231.54182.24154.24050.43896.93862.03859.13790.23764.63724.13745.23620.83597.13438.73435.63337.43331.53281.43266.73160.53145.93134.93116.03014.42997.53013.03001.62927.22920.52893.6NANANA
us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest ████▇▇▇▆▅▅▅▅▅▄▄▄▄▃▃▃▃▃▃▃▃▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁6019.05966.05888.05909.05748.35702.45405.15169.24899.64882.44785.74770.44550.74431.54382.24354.24250.44096.94062.04059.13990.23964.63924.13946.13821.73798.83640.53637.33539.13533.23483.23468.53362.33347.73281.83262.83161.33144.43159.93148.53074.33107.63079.4NANANA
us-gaap:CommonStockValue ██▄▄▆▆▆▆▆▆▆▆▅▅▅▅▅▅▅▅▅▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁3.03.02.02.02.52.52.52.42.42.42.42.42.32.32.32.32.32.32.32.32.31.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.1NANANA
us-gaap:AdditionalPaidInCapitalCommonStock ██████▆▅▄▄▄▄▄▃▃▃▃▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁2722.02712.02704.02693.02683.12674.12445.92236.92108.42100.02045.52038.21947.21851.41845.51838.21830.41699.21693.11686.01681.81673.71663.01656.01649.01631.61509.11508.91507.31506.41507.81506.91506.01504.41511.21512.11511.11510.01510.81509.11509.71507.51506.8NANANA
 us-gaap:CommonStocksIncludingAdditionalPaidInCapital us-gaap:ConsolidatedEntities srt:ParentCompanyNANA2706.0NANANA2448.0NANANA2048.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:RetainedEarningsAccumulatedDeficit ████▇▇▇▆▆▆▆▆▅▅▅▅▄▄▄▄▄▄▄▄▃▃▃▃▃▃▃▃▂▂▂▂▁▁▁▁▁▁▁3106.03063.02994.03026.02873.52833.72765.42739.12597.82587.32545.92539.52412.52389.42346.02324.82228.62205.92177.02181.02116.12098.92068.92097.01979.31973.91938.01934.51837.61832.21780.71767.31661.71648.41630.71612.11511.31495.21510.21500.21425.11421.11394.7NANANA
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax ▂▂▂▂▂▇▆▅▅█▇▃▄▃▃▃▃▃▃▃▃▃▃▂▂▂▂▃▃▃▃▂▂▂▂▂▂▂▂▂▂▁▁-1.0-1.0-1.0-1.0-0.62.01.31.01.02.41.7-0.20.1-0.5-0.5-0.4-0.4-0.4-0.4-0.4-0.4-0.4-0.4-0.6-0.6-0.6-0.6-0.2-0.2-0.2-0.2-0.8-0.8-0.8-0.8-0.8-0.8-0.8-0.8-0.6-0.6-1.4-1.4NANANA
 us-gaap:MinorityInterest us-gaap:EquityMethodInvestmentNonconsolidatedInvestee us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesNANA192.0NANANA208.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInOperatingActivities ▃▄▃▄▄▄▄▅▄▅▄█▁▄▄▇▄▆▅▄▆▅▄▅▅▆▄▆▄▆▄▅▅▅▅▅▄▅▄▄▅▅▆▅▆▅62.0145.065.0116.3159.5160.2151.2232.395.8181.185.5507.2-154.389.3100.0381.4168.3333.7205.6144.0281.7228.3175.9178.0202.6314.7127.7315.7154.6293.687.9219.8224.7198.6240.8261.1124.2215.090.0145.9205.5261.3289.3216.4290.0189.2
us-gaap:NetCashProvidedByUsedInInvestingActivities ▇█▅▅▆▆▃▅▆▄▆▁▇▇▃▃▅▅▄▅▅▆▅▇▆▆▅▅▆▆▆▆▆▇▁▆▆▇▇▇▇▆▅▆▇▆-152.0-38.0-272.0-286.7-212.7-179.6-426.2-254.1-242.2-364.8-251.1-637.2-93.3-85.2-424.0-445.9-322.8-303.6-414.7-271.0-280.8-220.0-306.2-142.7-219.4-250.9-277.3-271.4-192.2-176.8-241.5-191.0-202.5-119.7-637.8-195.9-186.7-135.1-145.7-165.3-107.8-233.3-260.0-210.9-163.4-232.2
 us-gaap:NetCashProvidedByUsedInInvestingActivities dei:LegalEntity lnt:Ipl▇█▆▆▆▆▅▅▅▄▆▁█▇▄▅▅▅▄▅▅▅▄▆▅▅▅▅▆▆▅▆▆▆▅▆▆▆▆▆▇▅▅▆0.098.0-99.0-76.8-72.3-52.9-182.9-129.6-132.7-221.8-100.5-489.3104.855.6-212.8-187.7-169.6-136.3-258.2-143.9-168.3-123.2-192.5-34.2-128.9-156.3-176.2-180.1-99.8-96.6-133.5-100.0-106.6-83.2-120.1-90.8-58.9-61.4-68.4-72.349.9-109.8-118.8-95.2NANA
 us-gaap:NetCashProvidedByUsedInInvestingActivities dei:LegalEntity lnt:Wpl▇▇▆▆▇▇▅▇▇▇▇▇▆▇▆▆▆▆▆▇▇▇▇▇▇█▇▇▇█▇▇▇█▁██████▇▇▇-134.0-119.0-148.0-205.2-135.3-124.5-222.3-116.9-97.7-120.3-138.8-143.2-196.8-128.7-195.5-147.8-173.1-149.3-152.2-121.1-114.2-91.4-98.6-97.6-83.6-78.4-86.3-82.7-80.6-70.5-83.5-88.1-88.2-76.1-497.7-79.1-69.8-63.6-63.0-71.1-47.0-124.3-136.0-114.0NANA
us-gaap:NetCashProvidedByUsedInFinancingActivities ▄▁▄▅▆▄▄▄▇▅▂█▆▃█▄▅▃▅▆▃▃▃▄▃▃▆▂▃▁▅▃▂▂█▂▄▂▃▃▁▂▃▂▂▃88.0-145.069.0154.7204.060.393.047.3302.8176.0-56.7365.8231.4-9.8342.766.4153.4-29.9132.6205.20.8-9.3-3.149.1-26.0-23.1195.5-49.539.3-112.1145.7-22.6-64.1-46.7377.1-54.962.4-60.421.4-12.0-146.7-61.2-7.0-39.6-95.77.9
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect ▄▄▂▄▇▅▂▅▇▄▁█▄▄▅▄▄▄-2.0-38.0-138.0-15.7150.840.9-182.025.5156.4-7.7-222.3235.8-16.2-5.718.73.0-2.81.9NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect dei:LegalEntity lnt:Ipl▄▄▂▄▇▅▂▇▄▄▁█▄▄▄▄▄▄0.0-39.0-135.0-18.2178.515.7-176.0178.9-0.5-5.5-223.9231.0-1.2-0.7-0.22.6-0.20.8NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect dei:LegalEntity lnt:WplNA-1.01.0-0.8-19.518.3-5.2-154.9159.8-4.51.53.1-1.3-18.320.7-2.00.7-2.1NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:DepreciationDepletionAndAmortization ██▇▆▅▄▄▄▄▃▁▁165.0164.0161.0155.6152.1146.3143.6143.8142.9136.9130.5129.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:IncreaseDecreaseInAccountsReceivable ▅▅▅▅▄▅▅▅▄▅▅▁█▅▄▃▃▃▄▄▄▄▃▄▃▃▄▃▂▄▄▃▃▄▃▃▃▃▃▄▃▃▃▄▃▃139.0126.0152.0118.178.9119.0112.5159.578.1121.6150.2-182.6360.2147.643.2-25.1-11.2-36.520.441.511.747.8-25.122.0-27.1-6.647.4-48.5-103.255.636.4-3.63.512.9-10.43.19.9-63.94.677.5-28.20.46.741.6-41.5-23.1
us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet ▆▆▂▆▆▅▃▆▆▄▄▇▄▆▂▄▆▄▄▄█▃▅▆▃▅▁▇▃▅▃▆▄▅▃▇▄▅▅▄▅▄▅▄▃▆35.024.0-75.040.744.210.1-40.344.427.7-22.0-9.775.8-10.835.1-55.9-3.539.2-18.5-11.6-17.189.1-44.8-1.532.5-31.45.8-95.271.3-36.70.9-50.534.7-11.63.7-35.254.7-19.213.94.2-17.614.3-22.022.4-13.8-47.631.3
us-gaap:NetCashProvidedByUsedInOperatingActivities ▃▄▃▄▄▄▄▅▄▅▄█▁▄▄▇▄▆▅▄▆▅▄▅▅▆▄▆▄▆▄▅▅▅▅▅▄▅▄▄▅▅▆▅▆▅62.0145.065.0116.3159.5160.2151.2232.395.8181.185.5507.2-154.389.3100.0381.4168.3333.7205.6144.0281.7228.3175.9178.0202.6314.7127.7315.7154.6293.687.9219.8224.7198.6240.8261.1124.2215.090.0145.9205.5261.3289.3216.4290.0189.2
us-gaap:NetIncomeLoss ▅▆▂█▄▅▄▇▃▄▃▇▃▄▃▅▃▃▂▄▃▃▁▆▂▃▂▅▂▃▂▅▂▂▂▅▂▁▂▄▂▂▂▅▂▁146.0174.066.0249.0136.9172.6114.0228.697.1127.787.8208.1102.9123.596.3171.496.8103.065.2131.086.499.136.6182.570.199.262.5155.964.3110.668.1160.267.880.172.3154.769.838.961.0125.955.379.752.0153.752.548.1
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInInvestingActivities ▇█▅▅▆▆▃▅▆▄▆▁▇▇▃▃▅▅▄▅▅▆▅▇▆▆▅▅▆▆▆▆▆▇▁▆▆▇▇▇▇▆▅▆▇▆-152.0-38.0-272.0-286.7-212.7-179.6-426.2-254.1-242.2-364.8-251.1-637.2-93.3-85.2-424.0-445.9-322.8-303.6-414.7-271.0-280.8-220.0-306.2-142.7-219.4-250.9-277.3-271.4-192.2-176.8-241.5-191.0-202.5-119.7-637.8-195.9-186.7-135.1-145.7-165.3-107.8-233.3-260.0-210.9-163.4-232.2
 us-gaap:NetCashProvidedByUsedInInvestingActivities dei:LegalEntity lnt:Ipl▇█▆▆▆▆▅▅▅▄▆▁█▇▄▅▅▅▄▅▅▅▄▆▅▅▅▅▆▆▅▆▆▆▅▆▆▆▆▆▇▅▅▆0.098.0-99.0-76.8-72.3-52.9-182.9-129.6-132.7-221.8-100.5-489.3104.855.6-212.8-187.7-169.6-136.3-258.2-143.9-168.3-123.2-192.5-34.2-128.9-156.3-176.2-180.1-99.8-96.6-133.5-100.0-106.6-83.2-120.1-90.8-58.9-61.4-68.4-72.349.9-109.8-118.8-95.2NANA
 us-gaap:NetCashProvidedByUsedInInvestingActivities dei:LegalEntity lnt:Wpl▇▇▆▆▇▇▅▇▇▇▇▇▆▇▆▆▆▆▆▇▇▇▇▇▇█▇▇▇█▇▇▇█▁██████▇▇▇-134.0-119.0-148.0-205.2-135.3-124.5-222.3-116.9-97.7-120.3-138.8-143.2-196.8-128.7-195.5-147.8-173.1-149.3-152.2-121.1-114.2-91.4-98.6-97.6-83.6-78.4-86.3-82.7-80.6-70.5-83.5-88.1-88.2-76.1-497.7-79.1-69.8-63.6-63.0-71.1-47.0-124.3-136.0-114.0NANA
us-gaap:PaymentsToAcquirePropertyPlantAndEquipment ▁▁▅▃▃▂█▃▂▄▇▄212.0214.0431.0351.0306.1277.9636.2351.4278.5374.0553.7380.6NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInFinancingActivities ▄▁▄▅▆▄▄▄▇▅▂█▆▃█▄▅▃▅▆▃▃▃▄▃▃▆▂▃▁▅▃▂▂█▂▄▂▃▃▁▂▃▂▂▃88.0-145.069.0154.7204.060.393.047.3302.8176.0-56.7365.8231.4-9.8342.766.4153.4-29.9132.6205.20.8-9.3-3.149.1-26.0-23.1195.5-49.539.3-112.1145.7-22.6-64.1-46.7377.1-54.962.4-60.421.4-12.0-146.7-61.2-7.0-39.6-95.77.9
us-gaap:ProceedsFromIssuanceOfLongTermDebt NANA200.00.0750.0300.00.0300.0650.00.00.0500.0NANA550.00.0NANA500.0NANANA0.0NANANA810.0NANANA250.0NANANA310.0NANANA0.00.0NANA0.0200.0NANA
 us-gaap:ProceedsFromIssuanceOfLongTermDebt dei:LegalEntity lnt:IplNANA0.00.0NANA0.0300.0NANA0.0500.0NANA250.0NANANA0.0NANANA0.0NANANA250.0NANANANANANANANANANANANANANANA0.0200.0NANA
us-gaap:RepaymentsOfLongTermDebt NANA3.00.3353.4300.33.0250.13.10.3252.6100.1NANA2.10.1NANA311.50.1NANA1.030.6NANA310.846.9NANA0.7NANANANANANANA0.70.0NANA0.7206.3NANA
 us-gaap:RepaymentsOfLongTermDebt dei:LegalEntity lnt:IplNANA0.00.0NANA0.00.0NANA250.0NANANA0.0NANANA0.00.0NANA0.00.0NANA0.038.4NANA0.0NANANANANANANANANANANA0.0NANANA
 us-gaap:RepaymentsOfLongTermDebt dei:LegalEntity lnt:WplNANA0.00.0NANA0.0250.0NANA0.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA0.00.0NANA
us-gaap:PaymentsOfDividendsCommonStock ██▇▇▇▇▆▆▆▆▅▅▅▅▄▄▄▄▄▄▄▄▃▃▃▃▃▃▃▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁101.0102.096.093.494.693.085.284.784.183.778.978.577.377.572.672.671.671.566.766.666.766.562.262.262.260.756.556.456.456.552.152.052.052.249.749.949.849.947.046.947.147.143.743.743.643.6
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value3.03.02.02.02.52.52.52.42.42.42.42.42.32.32.32.32.32.32.32.32.31.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.1
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStockValue dei:LegalEntity

lnt:Ipl


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value333333333333333333333333333333333333333333333333333333333333333333333333333333333333
Percentage of CommonStockValue1100.01100.01650.01650.01336.01336.01336.01391.71391.71391.71391.71391.71452.21452.21452.21452.21452.21452.21452.21452.21452.23036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.4
Percentage of Assets0.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.40.40.4
Percentage of Assets lnt:Ipl0.30.30.30.30.30.40.40.40.40.40.40.40.40.40.40.40.40.50.50.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.70.70.70.70.7

lnt:Wpl


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value666666666666666666666666666666666666666666666666666666666666666666666666666666666666
Percentage of CommonStockValue2200.02200.03300.03300.02648.02648.02648.02758.32758.32758.32758.32758.32878.32878.32878.32878.32878.32878.32878.32878.32878.36018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.2
Percentage of Assets0.40.40.40.40.40.40.40.40.40.40.40.40.50.50.50.50.50.50.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.70.70.70.70.70.7
Percentage of Assets lnt:Wpl0.91.01.01.01.01.01.01.01.01.11.11.11.11.11.21.21.21.21.31.21.21.21.31.31.31.31.31.31.41.41.41.41.41.41.41.61.61.61.61.71.71.7

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value250250250249244239238236235232231110110110110110110110110110110110110
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value250250249249244239237236235232231110110110110110110110110110110110110
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareBasic


Earnings
Period End2020-12-312020-09-302019-12-312019-09-302018-12-312018-09-302011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.250.990.460.950.360.870.511.10.460.660.431.350.430.39
Percentage of EarningsPerShareBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareDiluted


Earnings
Period End2020-12-312020-09-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.250.980.460.940.40.530.360.870.430.520.410.730.410.440.280.570.370.430.31.590.60.870.541.380.560.970.591.420.590.630.621.360.60.320.511.10.460.660.431.350.430.39
Percentage of EarningsPerShareDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Basic And Diluted

us-gaap:EarningsPerShareBasicAndDiluted

us-gaap:EarningsPerShareBasicAndDiluted


Earnings
Period End2021-03-312020-06-302020-03-312019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value0.680.540.70.40.530.360.870.430.520.40.730.410.440.280.570.370.850.31.590.60.870.541.380.560.970.591.420.590.630.621.360.60.320.511.10.460.66
Percentage of EarningsPerShareBasicAndDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Allocated Share Based Compensation Expense

us-gaap:AllocatedShareBasedCompensationExpense

us-gaap:AllocatedShareBasedCompensationExpense


Allocated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value2.03.06.05.02.72.7107.53.44.74.44.25.13.35.25.11.63.21.24.47.15.34.90.32.33.27.91.23.13.13.44.01.92.73.10.12.11.65.20.12.62.21.32.61.3
Percentage of AllocatedShareBasedCompensationExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue0.20.30.00.50.40.31.20.80.40.50.50.50.60.40.60.60.20.40.20.50.90.60.70.00.30.41.00.10.40.30.40.50.30.30.40.00.30.20.60.00.30.20.20.30.2

us-gaap:AllocatedShareBasedCompensationExpense dei:LegalEntity

lnt:Ipl


Allocated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value2.01.03.03.01.51.45.84.21.92.62.42.42.81.82.92.80.91.70.62.43.72.82.60.21.21.74.30.61.71.71.82.01.01.41.60.11.10.82.80.11.41.20.71.40.7
Percentage of AllocatedShareBasedCompensationExpense100.033.350.060.055.651.955.856.055.955.354.557.154.954.555.854.956.253.150.054.552.152.853.166.752.253.154.450.054.854.852.950.052.651.951.6100.052.450.053.8100.053.854.553.853.853.8
Percentage of RegulatedAndUnregulatedOperatingRevenue0.20.10.00.30.20.20.70.40.20.30.30.30.30.20.30.30.10.20.10.30.50.30.40.00.20.20.50.10.20.20.20.20.10.20.20.00.20.10.30.00.20.10.10.10.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl0.40.20.00.50.30.31.20.70.40.50.50.40.60.30.60.50.20.40.10.50.90.60.70.00.30.31.00.10.40.30.40.40.30.30.40.00.30.20.70.00.40.30.20.30.2

lnt:Wpl


Allocated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value1.01.02.02.01.21.14.13.01.41.81.81.72.11.32.32.10.61.40.61.93.12.32.20.11.01.43.30.51.31.31.51.70.91.11.30.10.90.72.10.11.00.90.51.10.5
Percentage of AllocatedShareBasedCompensationExpense50.033.333.340.044.440.739.440.041.238.340.940.541.239.444.241.237.543.850.043.243.743.444.933.343.543.841.841.741.941.944.142.547.440.741.9100.042.943.840.4100.038.540.938.542.338.5
Percentage of RegulatedAndUnregulatedOperatingRevenue0.10.10.00.20.20.10.50.30.20.20.20.20.30.10.30.20.10.20.10.20.40.30.30.00.10.20.40.10.20.10.20.20.10.10.20.00.10.10.20.00.10.10.10.10.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl0.30.30.00.60.40.31.10.80.40.40.50.50.60.30.60.60.20.40.20.50.90.60.70.00.30.40.90.10.40.30.40.50.30.30.40.00.30.20.60.00.30.20.10.30.2

Cost Of Goods And Services Sold

us-gaap:CostOfGoodsAndServicesSold

us-gaap:CostOfGoodsAndServicesSold


Cost
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value12113412313271122118127112123120129119
Percentage of CostOfGoodsAndServicesSold100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue14.814.90.014.39.413.313.512.914.212.513.813.914.7

us-gaap:CostOfGoodsAndServicesSold dei:LegalEntity

lnt:Ipl


Cost
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value79928693348483917787849284
Percentage of CostOfGoodsAndServicesSold65.368.769.970.547.569.170.372.068.971.370.571.970.5
Percentage of RegulatedAndUnregulatedOperatingRevenue9.710.20.010.14.59.29.59.39.88.99.710.010.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl17.418.80.016.87.916.316.815.417.515.817.216.917.8

lnt:Wpl


Cost
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value42423739373735353535353635
Percentage of CostOfGoodsAndServicesSold34.731.330.129.552.530.929.728.031.128.729.528.129.5
Percentage of RegulatedAndUnregulatedOperatingRevenue5.14.70.04.24.94.14.03.64.43.64.13.94.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl12.310.60.011.112.010.09.79.610.78.59.69.810.7

Costs And Expenses

us-gaap:CostsAndExpenses

us-gaap:CostsAndExpenses


Costs
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value641703705648595727719700640810752672664750726675616711697762626697660663608744712648647798724665614738649673581670785836747817732705640781
Percentage of CostsAndExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue78.578.00.070.478.079.481.770.781.082.186.172.481.581.984.874.580.583.387.582.483.082.789.373.884.883.088.676.986.283.887.076.885.686.086.575.984.287.589.481.991.286.588.074.186.487.8

us-gaap:CostsAndExpenses dei:LegalEntity

lnt:Ipl


Costs
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value344386380391343422415423366481439404397450423395353400399390363396373387348423407382377471426394348436364385325374377368355430394379344
Percentage of CostsAndExpenses53.754.953.960.357.758.057.860.457.359.458.560.159.760.058.258.657.556.457.351.258.056.856.558.557.356.957.159.058.459.059.059.356.759.156.157.255.955.948.144.047.652.753.853.853.7
Percentage of RegulatedAndUnregulatedOperatingRevenue42.142.80.042.545.046.147.242.746.448.850.343.648.749.149.443.646.246.950.142.248.147.050.443.148.647.250.745.350.449.551.345.548.650.848.543.547.148.943.036.043.445.547.439.846.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl75.678.90.070.779.581.483.670.983.186.889.073.983.685.689.675.084.289.092.075.688.386.593.676.891.286.694.580.391.789.192.279.890.991.492.677.590.294.093.576.095.190.194.670.988.4

lnt:Wpl


Costs
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value286305306262240281288263259317308266267297301279261307294282259296281272256316300260264322287265260297279283254289271287281313278282260
Percentage of CostsAndExpenses44.643.443.440.440.438.740.137.740.539.141.039.640.239.741.641.442.443.242.237.041.442.542.641.142.242.542.140.240.940.439.839.842.340.243.142.043.743.334.534.437.638.438.040.140.7
Percentage of RegulatedAndUnregulatedOperatingRevenue35.033.90.028.531.530.732.826.632.832.135.328.732.832.535.330.834.136.036.930.534.435.238.030.335.835.237.430.935.333.934.630.636.234.637.331.936.837.930.928.234.333.233.429.735.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl83.977.20.074.677.075.079.670.979.576.483.471.980.878.080.675.578.078.183.571.077.679.085.171.279.079.783.573.581.578.680.973.481.380.381.175.280.581.878.876.886.180.779.976.583.3

Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value1291465622912815313325110814293219116140981971181197713810512148210821196017077131821797895801928671701604310075219
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue15.816.20.024.916.916.815.125.413.714.510.723.714.315.311.521.815.414.09.715.013.914.46.623.411.513.37.620.210.413.89.920.711.011.110.721.712.59.38.015.75.310.69.023.1

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest dei:LegalEntity

lnt:Ipl


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value78702613258716015049583812356522610844362311435479.710016465.8781741208619251294175.98.4980.3283.5135
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest60.547.946.457.645.546.245.359.845.640.641.656.148.537.327.155.037.930.329.782.233.538.920.047.720.139.19.546.222.531.224.948.125.126.715.449.220.38.312.061.40.728.64.761.7
Percentage of RegulatedAndUnregulatedOperatingRevenue9.57.80.014.37.77.86.915.26.35.94.513.36.95.73.112.05.84.22.912.44.75.61.311.22.35.20.79.32.34.32.59.92.83.01.710.72.50.81.09.60.03.00.414.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl17.114.30.023.913.513.712.225.211.210.47.922.511.910.05.620.610.68.05.322.18.610.32.419.94.39.61.316.54.27.84.417.45.25.33.219.04.91.52.120.30.16.00.825.4

lnt:Wpl


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value316527685381599249804686466555725465481036469341015866478552816088516460875557657836656279
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest24.044.548.229.741.352.944.836.845.956.249.439.439.546.856.136.946.455.362.774.461.457.170.648.070.655.978.050.267.461.873.349.465.167.374.545.764.080.492.948.983.865.483.136.3
Percentage of RegulatedAndUnregulatedOperatingRevenue3.87.20.07.47.08.96.89.46.38.15.39.35.67.26.48.07.27.76.111.28.58.24.611.28.17.55.910.17.08.57.310.27.27.58.09.98.07.57.47.74.47.07.58.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl9.116.50.019.417.021.716.524.915.219.312.523.313.917.214.719.716.416.813.826.019.318.510.426.418.016.813.224.116.119.817.124.516.117.317.423.317.516.118.920.911.116.917.921.6

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxExpenseBenefit


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-17.0-28.0-10.0-20.0-8.3-18.7192311155.61113161.8262117127.5182110271120-1.9121320131710125.63916279.034-10.62223642334
Percentage of IncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue-2.1-3.10.0-2.2-1.1-2.02.22.31.41.50.61.31.71.80.22.92.82.11.50.82.42.61.53.11.62.3-0.21.51.82.21.62.01.51.40.74.42.43.61.03.3-1.32.42.86.73.13.9

us-gaap:IncomeTaxExpenseBenefit dei:LegalEntity

lnt:Ipl


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-10.0-12.0-10.0-19.0-3.8-14.1136.91.92.1-2.7-5.92.33.17.7-14.3-0.6-3.7-3.4-2.50.8-0.83.1-19.6-2.6-3.6-16.8-26.5-3.4-5.0-0.5-26.4-4.9-6.1-13.2-11.9-2.17.4-1.4-3.2-0.71.7-8.4355.8
Percentage of IncomeTaxExpenseBenefit58.842.9100.095.045.875.468.429.917.013.9-48.2-50.416.918.5427.8-54.8-2.8-21.0-27.9-33.34.4-3.728.4-70.5-23.2-17.6884.2-213.7-25.8-24.3-3.6-150.0-46.7-50.4-235.7-30.3-12.526.7-15.6-9.46.67.5-35.954.625.2
Percentage of RegulatedAndUnregulatedOperatingRevenue-1.2-1.30.0-2.1-0.5-1.51.50.70.20.2-0.3-0.60.30.30.9-1.6-0.1-0.4-0.4-0.30.1-0.10.4-2.2-0.4-0.4-2.1-3.1-0.5-0.5-0.1-3.0-0.7-0.7-1.8-1.3-0.31.0-0.2-0.3-0.10.2-1.03.70.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl-2.2-2.50.0-3.4-0.9-2.72.71.20.40.4-0.5-1.10.50.61.6-2.7-0.1-0.8-0.8-0.50.2-0.20.8-3.9-0.7-0.7-3.9-5.6-0.8-0.9-0.1-5.3-1.3-1.3-3.4-2.4-0.61.9-0.3-0.7-0.20.4-2.06.51.5

lnt:Wpl


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-7.0-19.0-2.0-5.0-4.5-8.29.9177.7148.1106.2111.8231620163320228.933182217231726222717201931192522261121272916
Percentage of IncomeTaxExpenseBenefit41.267.920.025.054.243.951.374.068.896.7144.687.245.669.6100.088.178.8115.9132.8449.3114.9104.681.7119.1167.9107.8-926.3192.7134.8127.7164.2154.5161.9169.4341.179.4113.791.0247.878.9-106.694.7116.746.570.4
Percentage of RegulatedAndUnregulatedOperatingRevenue-0.9-2.10.0-0.5-0.6-0.91.11.71.01.50.91.10.81.30.22.52.22.42.03.62.82.71.23.72.62.52.22.82.42.82.73.12.42.42.53.52.83.32.52.61.42.33.33.12.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl-2.1-4.80.0-1.4-1.4-2.22.74.62.43.52.22.81.93.10.56.25.05.24.68.56.26.02.78.75.85.64.96.75.56.46.37.55.35.55.58.36.17.16.57.23.55.57.88.15.2

Income Taxes Paid Net

us-gaap:IncomeTaxesPaidNet

us-gaap:IncomeTaxesPaidNet


Income
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1.0-11.04.90.1-19.71.74.3-6.80.00.05.00.0-0.10.09.12.31.54.04.30.00.00.10.0-0.10.0-1.50.1-3.90.10.0-12.02.3-19.50.1-0.8-0.1-7.80.00.0-3.0-109.80.3-5.9-0.8
Percentage of IncomeTaxesPaidNet100.0100.0100.0100.0100.0100.0100.0100.00.00.0100.00.0100.00.0100.0100.0100.0100.0100.00.00.0100.00.0100.00.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.00.00.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue0.0-1.20.60.0-2.20.20.5-0.70.00.00.60.0-0.00.01.20.30.20.40.60.00.00.00.0-0.00.0-0.20.0-0.40.00.0-1.70.3-2.60.0-0.1-0.0-0.90.00.0-0.3-13.20.0-0.8-0.1

us-gaap:IncomeTaxesPaidNet dei:LegalEntity

lnt:Ipl


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-20.0-7.06.019-7.40.11.33.9-5.3-6.8211.90.50.04.6-1.3-14.52.611-13.614-1.111-12.5-12.4-6.20.9-12.0-10.51.5-10.88.5-2.64.8144.1-1.0-14.410-0.5-6.522-106.12.6
Percentage of IncomeTaxesPaidNet0.00.0600.0-175.5-151.0100.0-6.6229.4-123.3100.00.00.010.00.0-4600.00.0-159.3113.0786.7-340.0325.60.00.0-12500.00.06200.00.0800.0-10500.0-38.5-10800.00.021.7208.7-74.94100.0125.014400.0-132.10.00.0-733.396.6866.7
Percentage of RegulatedAndUnregulatedOperatingRevenue-2.4-0.80.02.1-1.00.00.10.4-0.7-0.72.40.20.10.00.5-0.1-1.90.31.5-1.51.9-0.11.6-1.4-1.7-0.70.1-1.4-1.40.2-1.31.0-0.40.61.90.5-0.1-1.91.2-0.0-0.82.3-12.70.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl-4.4-1.40.03.5-1.70.00.30.7-1.2-1.24.30.30.10.01.0-0.2-3.50.62.7-2.63.4-0.23.0-2.5-3.2-1.30.2-2.5-2.50.3-2.31.7-0.71.03.70.8-0.3-3.62.5-0.1-1.74.6-25.40.5

lnt:Wpl


Income
Period End2020-12-312020-09-302019-12-312019-09-302018-12-312018-09-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-8.0-3.9210.5-25.23.3-11.80.9190.0-8.2-16.6-10.47.4-2.66.312-9.13.5-0.710.0-0.623-9.1-17.425-11.2-7.93.612-14.2-1.3-2.6-33.2-17.7-7.8
Percentage of IncomeTaxesPaidNet-800.035.5-111.229.40.00.011800.00.0212.10.0-546.7-415.0-241.90.00.06300.00.09100.00.046.710000.015.423500.00.0145.01126.157.4-7900.0-450.0-12200.0182.10.00.01106.716.1-2600.0
Percentage of RegulatedAndUnregulatedOperatingRevenue0.0-0.42.50.1-2.90.4-1.40.12.50.0-1.0-1.8-1.40.9-0.40.71.8-1.00.4-0.11.3-0.12.8-1.1-2.43.0-1.5-0.90.51.6-1.6-0.1-0.3-3.5-2.1-0.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl0.0-1.16.00.1-6.80.9-3.10.25.80.0-2.3-4.2-3.12.0-0.81.63.9-2.31.0-0.23.1-0.16.6-2.5-5.47.0-3.2-2.11.13.4-4.1-0.3-0.8-8.5-5.1-2.1

Interest Expense

us-gaap:InterestExpense

us-gaap:InterestExpense


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value69696868696869686966636361595653525251484848474646464544454545424242403838383838404040413940
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue8.47.70.07.49.17.57.96.98.86.77.26.87.56.56.65.96.96.16.45.36.45.76.45.26.55.25.75.36.04.75.44.95.95.05.44.35.65.14.43.84.94.34.94.45.34.6

us-gaap:InterestExpense dei:LegalEntity

lnt:Ipl


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value343535353434343131292830302928272727272525242523232422212222221919191919191919191919202120
Percentage of InterestExpense49.350.751.551.550.050.149.646.445.544.345.648.049.650.351.151.852.853.054.152.352.151.952.551.351.451.750.149.150.149.849.646.146.446.048.250.950.850.650.550.449.049.049.551.151.3
Percentage of RegulatedAndUnregulatedOperatingRevenue4.23.90.03.84.63.83.93.24.03.03.33.33.73.33.43.13.63.23.52.83.33.03.42.63.32.72.82.63.02.42.72.32.72.32.62.22.82.62.21.92.42.12.42.22.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl7.57.20.06.38.16.66.95.37.15.35.85.66.45.76.15.36.66.16.44.96.15.46.34.76.34.95.34.65.54.34.84.05.14.15.03.95.44.94.84.05.34.24.84.05.2

lnt:Wpl


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value262626262725242526252424242424232322222222222223232323212121212121212019192019192020202018
Percentage of InterestExpense37.737.738.238.239.236.436.037.237.738.938.438.240.141.743.642.943.843.844.246.947.747.748.149.850.149.650.847.146.846.746.949.950.150.050.451.451.651.451.651.449.549.549.347.747.2
Percentage of RegulatedAndUnregulatedOperatingRevenue3.22.90.02.83.62.72.82.63.32.62.82.63.02.72.92.53.02.72.82.53.02.73.12.63.22.62.92.52.82.22.52.43.02.52.72.22.92.62.31.92.42.12.42.12.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl7.66.60.07.48.76.76.96.88.06.26.66.57.46.56.66.26.95.86.45.86.96.16.96.07.25.86.45.96.55.16.05.96.75.86.05.26.35.65.85.36.15.25.85.46.0

Interest Paid Net

us-gaap:InterestPaidNet

us-gaap:InterestPaidNet


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value78597758736473626962755165545453535151445144504053404941494143414343393838383838404040423547
Percentage of InterestPaidNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue9.56.50.06.49.67.18.36.38.86.48.75.68.05.96.35.97.06.16.54.96.85.36.94.57.44.56.14.96.54.35.24.86.05.15.34.35.65.14.43.84.94.34.84.54.75.3

us-gaap:InterestPaidNet dei:LegalEntity

lnt:Ipl


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3237323730402735223631283228272827282722272227182918251925191919202119191919191919191922
Percentage of InterestPaidNet41.062.741.663.541.963.037.857.431.957.241.155.848.852.051.253.151.354.852.650.653.050.853.445.556.145.852.246.052.746.645.846.447.248.550.050.551.350.051.049.749.248.049.452.0
Percentage of RegulatedAndUnregulatedOperatingRevenue3.94.10.04.14.04.53.13.62.83.63.63.13.93.13.23.13.63.33.42.53.62.73.72.04.22.13.22.33.52.02.42.22.82.52.62.22.92.52.21.92.42.02.42.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl7.07.60.06.87.17.95.66.05.16.56.35.36.75.45.95.46.56.36.34.46.64.96.83.67.83.85.94.06.33.64.33.95.34.45.03.95.54.94.94.05.34.04.74.2

lnt:Wpl


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3121312128212822292229192721232224212322232123222322192319231923192316231623162316231623
Percentage of InterestPaidNet39.735.640.336.238.733.039.135.841.835.839.036.942.539.743.641.545.142.346.049.046.449.247.056.244.856.238.856.738.756.044.256.044.253.841.460.542.760.642.760.341.258.540.954.5
Percentage of RegulatedAndUnregulatedOperatingRevenue3.82.30.02.33.72.33.22.23.72.33.42.13.42.32.82.43.12.63.02.43.22.63.22.53.32.52.42.82.52.42.32.72.72.72.22.62.43.11.92.32.02.52.02.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl9.15.30.06.19.15.77.96.09.05.48.05.28.45.66.36.07.25.66.85.57.15.87.25.97.45.75.36.65.95.75.46.56.06.34.86.15.26.64.86.25.06.04.76.3

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value14617466249136172114228971278720810212396171961036513186993618270996215564110681606780721546938611255579521535248
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue17.919.30.027.117.918.813.023.112.312.910.122.412.613.511.218.912.612.18.214.211.411.74.920.39.811.17.818.58.611.68.218.59.49.39.617.410.15.16.912.36.78.46.216.27.15.4

us-gaap:NetIncomeLoss dei:LegalEntity

lnt:Ipl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value88823615162854714347554112954491812345392611634488.012019502210520462111224312510619-1.59.81011.02711100219.7
Percentage of NetIncomeLoss60.347.154.560.645.549.441.462.948.943.847.462.052.739.919.671.846.838.640.689.139.848.621.965.827.450.836.267.432.541.631.070.336.439.335.468.828.1-3.916.180.51.834.022.965.540.420.2
Percentage of RegulatedAndUnregulatedOperatingRevenue10.89.10.016.48.29.35.414.56.05.74.813.96.65.42.213.65.94.73.312.64.65.71.113.32.75.62.812.52.84.82.513.03.43.73.412.02.8-0.21.19.90.12.91.410.62.91.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl19.316.80.027.314.416.49.524.110.810.18.423.611.49.44.023.310.88.86.122.68.410.52.023.85.010.35.222.15.18.74.622.86.46.66.521.45.4-0.42.420.90.35.72.918.85.42.1

lnt:Wpl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value38842973578949754265387639545349384532694347246739442961345438613443415636314251254435503037
Percentage of NetIncomeLoss26.048.343.929.342.151.943.733.043.351.443.336.738.743.755.229.139.444.249.853.150.647.466.737.256.345.247.739.553.849.556.138.350.754.456.736.751.782.070.040.845.255.767.532.557.576.9
Percentage of RegulatedAndUnregulatedOperatingRevenue4.79.30.07.97.59.85.77.65.36.74.48.24.95.96.25.55.05.34.17.55.85.63.37.65.55.03.77.34.65.84.67.14.85.15.56.45.24.24.95.03.14.74.25.34.14.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl11.121.30.020.818.423.913.720.312.915.810.320.612.014.114.213.511.411.69.217.513.112.57.417.712.211.38.317.410.713.410.717.010.811.811.915.111.49.012.413.77.611.410.113.59.79.4

us-gaap:NetIncomeLoss dei:LegalEntity, us-gaap:StatementEquityComponents

lnt:Wpl, us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value38842973578950764265
Percentage of NetIncomeLoss26.048.343.929.342.151.943.933.243.351.4
Percentage of RegulatedAndUnregulatedOperatingRevenue4.79.30.07.97.59.85.77.75.36.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.0

Net Income Loss Available To Common Stockholders Basic

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value14417164246134170111226941258520510012093168941006212883963417967966015361108651576569681506534571225173471494743
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue17.619.00.026.717.618.612.722.812.012.79.822.112.313.211.018.612.311.87.913.911.111.44.620.09.410.87.518.28.211.37.918.29.18.19.117.09.54.66.511.96.27.85.715.76.44.9

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic dei:LegalEntity

lnt:Ipl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value86793414859824414145533912651461612042372411431455.511716472010218431811022222210316-4.76.698-2.3218.096175.8
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic59.746.253.160.244.548.640.162.447.642.645.861.651.538.617.571.345.437.138.388.938.047.316.165.324.749.533.566.929.840.228.269.834.032.832.868.525.2-13.511.680.6-4.529.516.964.936.413.4
Percentage of RegulatedAndUnregulatedOperatingRevenue10.58.80.016.17.89.05.114.25.75.44.513.66.35.11.913.35.64.43.012.34.25.40.713.12.35.32.512.22.54.62.212.73.12.73.011.62.4-0.60.89.6-0.32.31.010.22.30.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl18.916.20.026.813.815.99.023.710.29.67.923.110.98.93.522.810.28.35.522.17.89.91.423.34.49.84.721.54.58.24.022.25.84.85.720.84.6-1.21.620.3-0.64.51.918.14.51.3

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic dei:LegalEntity, us-gaap:StatementEquityComponents

lnt:Ipl, us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value8679341485982441414553391265146
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic59.746.253.160.244.548.640.162.447.642.645.861.651.538.6
Percentage of RegulatedAndUnregulatedOperatingRevenue10.58.80.016.17.89.05.114.25.75.44.513.66.35.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

us-gaap:UnregulatedOperation, us-gaap:AllOtherSegments


Net
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-03-31
Value208.02517-2.29.47.66.12.78.920-7.56.710-54.78.84.4-5.0114.2-10.88.89.8-13.78.75.0-8.5148.58.2
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic13.94.710.212.6-1.34.28.04.91.38.916.7-4.47.110.8-42.610.54.6-2.817.64.3-7.014.29.1-8.713.37.2-5.621.424.411.2
Percentage of RegulatedAndUnregulatedOperatingRevenue2.40.92.72.2-0.20.91.00.60.31.12.2-0.80.91.3-5.91.20.5-0.61.70.5-1.31.21.0-1.61.20.6-1.02.01.10.9
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:UnregulatedOperation us-gaap:AllOtherSegments95.247.1156.289.9-10.243.533.236.126.284.8229.5-80.665.0104.9-479.894.646.3-42.7115.537.2-86.463.372.6-121.259.242.0-63.9101.468.073.2

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic us-gaap:StatementBusinessSegments

lnt:UtilityBusiness


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value1241636322111717294216871197720291100491768789551837592291845592491645398561715664621595126481486542146
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic86.195.398.489.887.4101.384.895.892.095.190.498.791.183.353.2104.492.989.288.8142.689.595.485.9102.882.495.782.0107.085.890.986.6108.786.792.891.7105.678.675.685.1122.088.889.497.9
Percentage of RegulatedAndUnregulatedOperatingRevenue15.218.10.024.015.418.810.721.911.012.18.821.811.211.05.819.411.410.57.019.810.010.94.020.67.810.36.119.57.110.36.819.87.97.68.317.97.53.45.514.66.95.115.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:UtilityBusiness15.618.40.024.415.819.30.022.411.312.30.022.111.411.10.019.611.610.60.020.110.111.00.020.87.910.40.019.87.210.50.020.08.07.70.018.27.73.50.017.37.50.016.1

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value144171642461341701112269412585205100120
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue17.619.00.026.717.618.612.722.812.012.79.822.112.313.2
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Nonoperating Income Expense

us-gaap:NonoperatingIncomeExpense

us-gaap:NonoperatingIncomeExpense


Nonoperating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-47.0-52.0-56.0-43.0-39.5-34.4-27.6-38.5-41.5-34.0-28.0-36.3-34.7-25.4-31.6-34.0-31.3-23.7-22.2-23.7-23.6-24.1-30.6-25.5-26.4-33.2-30.5-24.6-25.5-23.0-25.8-22.3-24.3-25.5-20.9-21.4-22.6-24.6-23.5-25.1-27.3-26.8-24.7-27.0-25.0-26.2
Percentage of NonoperatingIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue-5.8-5.80.0-4.7-5.2-3.8-3.1-3.9-5.3-3.4-3.2-3.9-4.3-2.8-3.7-3.7-4.1-2.8-2.8-2.6-3.1-2.9-4.1-2.8-3.7-3.7-3.8-2.9-3.4-2.4-3.1-2.6-3.4-3.0-2.8-2.4-3.3-3.2-2.7-2.5-3.3-2.8-3.0-2.8-3.4-2.9

us-gaap:NonoperatingIncomeExpense dei:LegalEntity

lnt:Ipl


Nonoperating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-33.0-33.0-37.0-30.0-30.2-25.6-20.9-22.9-25.1-15.5-15.5-19.9-21.2-23.2-22.6-23.1-21.6-13.5-11.8-11.7-12.8-14.6-15.9-16.6-17.2-18.7-18.0-15.3-16.5-16.5-15.6-13.8-14.9-15.7-16.6-17.4-17.9-18.0-17.9-18.3-18.2-18.3-19.2-20.1-18.2
Percentage of NonoperatingIncomeExpense70.263.566.169.876.574.475.759.560.545.655.454.861.191.371.567.969.057.053.249.454.260.652.065.165.256.359.062.264.771.760.561.961.361.679.481.379.273.276.272.966.768.377.774.472.8
Percentage of RegulatedAndUnregulatedOperatingRevenue-4.0-3.70.0-3.3-4.0-2.8-2.4-2.3-3.2-1.6-1.8-2.1-2.6-2.5-2.6-2.5-2.8-1.6-1.5-1.3-1.7-1.7-2.1-1.8-2.4-2.1-2.2-1.8-2.2-1.7-1.9-1.6-2.1-1.8-2.2-2.0-2.6-2.4-2.0-1.8-2.2-1.9-2.3-2.1-2.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl-7.3-6.70.0-5.4-7.0-4.9-4.2-3.8-5.7-2.8-3.1-3.6-4.5-4.4-4.8-4.4-5.1-3.0-2.7-2.3-3.1-3.2-4.0-3.3-4.5-3.8-4.2-3.2-4.0-3.1-3.4-2.8-3.9-3.3-4.2-3.5-5.0-4.5-4.4-3.8-4.9-3.8-4.6-3.8-4.7

lnt:Wpl


Nonoperating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-24.0-25.0-24.0-21.0-18.6-12.4-14.1-15.7-17.3-17.8-15.2-17.7-17.4-18.3-17.8-17.9-18.9-20.1-9.5-11.7-10.5-9.2-15.0-9.3-10.0-13.9-12.0-8.4-7.6-6.6-7.1-7.4-8.3-8.6-5.2-5.5-6.3-7.5-8.2-8.6-9.2-9.0-7.7-6.9-5.9
Percentage of NonoperatingIncomeExpense51.148.142.948.847.136.051.140.841.752.454.348.850.172.056.352.660.484.842.849.444.538.249.036.537.941.939.334.129.828.727.533.234.233.724.925.727.930.534.934.333.733.631.225.623.6
Percentage of RegulatedAndUnregulatedOperatingRevenue-2.9-2.80.0-2.3-2.4-1.4-1.6-1.6-2.2-1.8-1.7-1.9-2.1-2.0-2.1-2.0-2.5-2.4-1.2-1.3-1.4-1.1-2.0-1.0-1.4-1.5-1.5-1.0-1.0-0.7-0.9-0.9-1.2-1.0-0.7-0.6-0.9-1.0-0.9-0.8-1.1-1.0-0.9-0.7-0.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl-7.0-6.30.0-6.0-6.0-3.3-3.9-4.2-5.3-4.3-4.1-4.8-5.3-4.8-4.8-4.8-5.6-5.1-2.7-2.9-3.1-2.4-4.5-2.4-3.1-3.5-3.3-2.4-2.3-1.6-2.0-2.1-2.6-2.3-1.5-1.5-2.0-2.1-2.4-2.3-2.8-2.3-2.2-1.9-1.9

Operating Income Loss

us-gaap:OperatingIncomeLoss

us-gaap:OperatingIncomeLoss


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value17619811227216818816029014917612125615116512923114914299162128145792351091529119410315410820110312010121310895931857212799246100109
Percentage of OperatingIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue21.522.00.029.622.020.618.329.319.017.913.927.618.518.115.225.519.516.712.517.617.017.310.726.215.217.011.423.113.816.213.023.214.414.013.524.115.812.510.618.18.813.512.025.913.612.2

us-gaap:OperatingIncomeLoss dei:LegalEntity

lnt:Ipl


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value11110363162889681173747354143777549131664934125486225117336523933457361003441291123523261161847221554538
Percentage of OperatingIncomeLoss63.152.056.259.652.851.450.559.849.741.644.855.951.445.637.956.944.434.734.977.437.342.532.349.631.042.826.148.232.937.333.349.733.634.128.552.432.525.028.162.925.736.922.763.144.935.1
Percentage of RegulatedAndUnregulatedOperatingRevenue13.611.40.017.611.610.69.217.59.47.46.215.49.58.35.714.58.75.84.413.66.47.33.513.04.77.33.011.14.56.04.311.54.84.83.912.65.13.13.011.42.35.02.716.46.14.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl24.421.10.029.320.518.616.429.116.913.211.026.116.414.410.425.015.811.08.024.411.713.56.423.28.813.45.519.78.310.97.820.29.18.67.422.59.86.06.524.04.99.95.429.111.68.4

lnt:Wpl


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value559051897193731086798611046384729073865811575784911068805993608767955972659361647386457470865269
Percentage of OperatingIncomeLoss31.245.545.532.742.749.845.937.344.755.550.540.741.950.756.139.249.460.258.370.758.354.062.246.862.752.865.148.258.156.962.447.657.860.264.343.756.567.678.346.963.258.570.235.251.963.9
Percentage of RegulatedAndUnregulatedOperatingRevenue6.710.00.09.79.410.28.410.98.59.97.011.27.89.28.510.09.610.17.312.49.99.36.712.39.59.07.411.18.09.28.111.18.38.58.710.58.98.48.38.55.67.98.49.17.17.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl16.122.80.025.423.025.020.429.120.523.616.628.119.222.019.424.522.021.916.529.022.421.014.928.821.020.316.526.518.521.419.126.618.719.718.924.819.518.221.223.213.919.320.123.516.717.7

us-gaap:OperatingIncomeLoss dei:LegalEntity, us-gaap:StatementBusinessSegments

lnt:Ipl, lnt:Electric


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value10772501598267691756846421447357461386233381254443251193340169429262699291716109336.719117162726151
Percentage of OperatingIncomeLoss60.836.444.658.548.835.643.060.346.026.535.056.548.634.735.959.741.823.738.277.434.629.731.850.631.126.418.248.628.117.224.849.528.514.316.651.230.47.020.663.523.521.826.161.6
Percentage of RegulatedAndUnregulatedOperatingRevenue13.18.00.017.310.87.37.917.78.74.74.915.69.06.35.415.28.24.04.813.65.95.13.413.34.74.52.111.23.92.83.211.54.12.02.312.34.80.92.211.52.13.03.116.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Electric26.618.70.030.621.115.80.031.217.611.10.028.417.414.20.028.316.89.50.026.112.212.00.025.510.011.10.021.78.27.10.021.88.94.90.024.010.32.30.026.55.28.40.030.8

lnt:Ipl, lnt:Gas


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value3.030161.05.22712-4.24.22612-3.12.5166.1-2.12.4140.2-1.40.9152.4-2.9-2.4203.6-2.81.6237.2-0.72.6208.60.60.8145.5-1.30.6155.5-0.7
Percentage of OperatingIncomeLoss1.715.214.30.43.114.57.9-1.42.814.99.9-1.21.710.24.7-0.91.610.10.2-0.90.710.83.0-1.2-2.213.53.9-1.41.515.16.6-0.32.517.18.50.30.714.95.9-0.70.812.45.5-0.3
Percentage of RegulatedAndUnregulatedOperatingRevenue0.43.30.00.10.73.01.4-0.40.52.71.4-0.30.31.80.7-0.20.31.70.0-0.20.11.90.3-0.3-0.32.30.4-0.30.22.40.9-0.10.42.41.10.10.11.90.6-0.10.11.70.7-0.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Gas7.033.00.04.215.332.90.0-16.910.921.10.0-11.65.915.60.0-7.76.517.30.0-5.92.618.80.0-12.6-8.118.50.0-9.83.717.20.0-2.86.218.10.02.03.015.30.0-4.71.612.00.0-2.5

lnt:Ipl, lnt:OtherUtility


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value1.01.0-3.02.01.42.4-0.22.61.40.4-0.11.51.71.2-3.5-4.41.51.4-3.51.42.62.8-2.00.52.34.63.62.03.47.72.11.12.73.23.51.91.53.01.50.31.03.4
Percentage of OperatingIncomeLoss0.60.5-2.70.70.81.3-0.10.90.90.2-0.10.61.10.7-2.7-1.91.01.0-3.50.92.01.9-2.50.22.13.03.91.03.35.01.90.52.62.73.40.91.43.11.60.21.42.7
Percentage of RegulatedAndUnregulatedOperatingRevenue0.10.10.00.20.20.3-0.00.30.20.0-0.00.20.20.1-0.4-0.50.20.2-0.40.20.30.3-0.30.10.30.50.40.20.50.80.30.10.40.40.50.20.20.40.20.00.10.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:OtherUtility10.08.30.020.014.621.60.024.113.33.70.012.816.210.00.0-40.013.512.50.015.421.521.70.03.917.730.30.017.225.040.50.09.022.923.90.016.511.623.40.02.28.722.1

lnt:Wpl, lnt:Electric


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value577544927079661086479571046169649473736011874665011367645196606758100565655935852678845615589
Percentage of OperatingIncomeLoss32.437.939.333.841.642.141.537.442.745.047.440.640.541.849.740.749.051.460.572.858.245.563.848.161.542.156.549.358.244.053.949.754.746.754.443.854.054.872.047.962.948.055.636.2
Percentage of RegulatedAndUnregulatedOperatingRevenue7.08.30.010.09.28.67.611.08.18.16.611.27.57.67.510.49.68.67.612.89.97.96.812.69.37.26.411.48.07.17.011.57.96.67.410.58.56.87.78.75.56.56.79.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:Electric18.123.80.027.624.425.90.030.621.424.60.029.520.222.80.026.823.722.80.031.024.021.60.030.922.320.90.028.720.822.50.029.420.019.90.026.120.118.80.025.015.321.20.025.5

lnt:Wpl, lnt:Gas


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.01410.0-2.01.9149.6-0.53.0186.31.12.9149.7-0.31.5133.5-2.31.0133.6-2.80.4158.9-1.61.11910-2.73.016100.22.8138.3-1.50.32014-2.2
Percentage of OperatingIncomeLoss0.07.18.9-0.71.17.66.0-0.22.010.75.20.41.98.87.5-0.11.09.53.5-1.40.88.94.5-1.20.410.39.7-0.81.112.89.8-1.32.913.810.60.12.614.18.9-0.80.415.714.1-0.9
Percentage of RegulatedAndUnregulatedOperatingRevenue0.01.60.0-0.20.21.61.1-0.10.41.90.70.10.41.61.1-0.00.21.60.4-0.20.11.50.5-0.30.11.71.1-0.20.12.11.3-0.30.41.91.40.00.41.80.9-0.10.02.11.7-0.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:Gas0.017.70.0-11.17.620.70.0-3.011.220.70.06.111.018.80.0-1.65.819.10.0-14.74.419.10.0-18.81.818.00.0-8.63.318.80.0-17.89.620.00.01.212.118.20.0-7.91.120.70.0-12.0

lnt:Wpl, lnt:OtherUtility


Operating
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value-2.01.0-1.0-0.20.3-2.70.20.0-0.4-2.5-0.9-0.80.2-1.4-3.3-1.0-1.0-5.7-1.0-0.8-0.6-4.8-0.30.90.7-1.1-0.6-1.20.2-1.3-1.40.2-0.3-0.8-0.40.0-1.3-2.4-0.2-0.1-6.7
Percentage of OperatingIncomeLoss-1.10.5-0.4-0.10.2-1.70.10.0-0.2-2.1-0.4-0.50.1-1.1-1.4-0.7-0.7-5.7-0.6-0.6-0.4-6.1-0.10.80.5-1.2-0.3-1.20.1-1.2-0.70.2-0.2-0.8-0.20.0-1.4-2.6-0.1-0.1-5.2
Percentage of RegulatedAndUnregulatedOperatingRevenue-0.20.1-0.1-0.00.0-0.30.00.0-0.0-0.3-0.1-0.10.0-0.2-0.4-0.1-0.1-0.7-0.1-0.1-0.1-0.6-0.00.10.1-0.1-0.1-0.20.0-0.2-0.20.0-0.0-0.1-0.00.0-0.2-0.3-0.0-0.0-0.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:OtherUtility0.0100.00.0-40.060.00.050.00.0-100.00.0-150.0-400.016.70.0-1650.0-250.0-200.00.0-333.3-266.7-200.00.0-60.050.058.30.0-100.0-60.05.30.0-26.93.3-7.90.0-57.10.0-144.40.0-10.0-5.6-515.4

us-gaap:OperatingIncomeLoss us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

us-gaap:UnregulatedOperation, us-gaap:AllOtherSegments


Operating
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-03-31
Value10.05.0217.7-2.28.48.35.28.8106.19.09.37.3-78.35.65.18.66.96.67.09.39.05.58.86.98.3117.15.4
Percentage of OperatingIncomeLoss5.72.57.74.6-1.22.95.52.93.46.73.73.96.25.1-48.24.43.53.66.34.33.69.05.82.78.55.73.910.97.44.2
Percentage of RegulatedAndUnregulatedOperatingRevenue1.20.62.31.0-0.20.81.10.50.91.20.71.01.20.9-8.50.70.61.01.00.70.81.20.90.61.20.80.91.70.90.6
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:UnregulatedOperation us-gaap:AllOtherSegments47.629.4131.240.7-10.238.936.230.885.496.269.396.890.370.9-686.860.253.773.567.058.456.066.966.748.759.958.062.485.656.848.2

us-gaap:OperatingIncomeLoss us-gaap:StatementBusinessSegments

lnt:Electric


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value164147942511521461362831321261002481341261112321351079824411910975232100104681908994851998573722039159862068981241
Percentage of OperatingIncomeLoss93.274.283.992.390.577.684.597.888.771.582.497.189.276.585.7100.590.875.098.7150.292.875.395.698.792.668.574.797.986.361.278.699.183.261.071.195.084.461.892.6111.369.981.797.8
Percentage of RegulatedAndUnregulatedOperatingRevenue20.116.30.027.319.916.015.528.716.812.811.426.816.513.813.025.617.712.612.426.415.813.010.225.914.111.78.522.611.99.910.323.012.08.69.622.913.37.79.820.29.49.825.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Electric22.921.00.029.522.520.00.031.019.217.00.028.918.617.90.027.719.915.80.028.317.716.40.027.915.815.60.024.713.814.00.025.014.011.60.024.915.010.30.025.914.40.028.6

lnt:Gas


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value3.04426-1.07.14122-4.77.24518-2.05.43115-2.43.9283.7-3.71.9286.0-5.7-2.03612-4.42.74317-3.45.637190.83.62713-2.83519-2.9
Percentage of OperatingIncomeLoss1.722.223.2-0.44.222.113.9-1.64.825.615.1-0.83.619.012.2-1.02.619.63.7-2.31.519.77.6-2.4-1.823.713.7-2.32.627.916.4-1.75.430.919.10.43.329.014.8-1.528.119.6-1.2
Percentage of RegulatedAndUnregulatedOperatingRevenue0.44.90.0-0.10.94.52.5-0.50.94.62.1-0.20.73.41.8-0.30.53.30.5-0.40.33.40.8-0.6-0.34.01.6-0.50.44.52.1-0.40.84.32.60.10.53.61.6-0.33.82.4-0.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Gas4.325.90.0-2.412.127.30.0-11.311.020.90.0-4.57.917.00.0-5.26.218.10.0-9.43.318.90.0-15.0-3.918.30.0-9.33.517.90.0-8.57.618.90.01.77.216.60.0-6.015.70.0-6.2

lnt:OtherUtility


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value-1.02.0-6.01.01.22.7-2.92.81.40.0-2.60.60.91.4-4.9-7.70.50.4-9.20.41.82.2-6.80.23.25.32.51.42.27.90.8-0.32.92.92.71.51.51.7-0.90.1-3.3-8.34.2
Percentage of OperatingIncomeLoss-0.61.0-5.40.40.71.4-1.81.00.90.0-2.10.20.60.8-3.8-3.30.30.3-9.20.21.41.5-8.60.12.93.52.70.72.15.10.7-0.12.82.42.70.71.41.8-1.00.1-2.6-8.31.7
Percentage of RegulatedAndUnregulatedOperatingRevenue-0.10.20.00.10.20.3-0.30.30.20.0-0.30.10.10.2-0.6-0.80.10.0-1.20.00.20.3-0.90.00.40.60.30.20.30.80.1-0.00.40.30.40.20.20.2-0.10.0-0.3-1.00.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:OtherUtility-10.015.40.010.011.923.30.025.012.80.00.04.98.410.60.0-68.84.33.40.04.314.516.70.01.521.632.30.011.514.134.60.0-1.716.316.90.012.310.912.40.00.6-19.80.026.4

lnt:UtilityBusiness


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value16619311425116019015528114117111524714115912222214013593240123140742271021468318794145104195941139420596889920312192242
Percentage of OperatingIncomeLoss94.397.5101.892.395.4101.296.497.194.597.195.396.693.396.394.196.193.894.993.2148.295.696.594.696.493.795.791.196.491.094.295.897.391.594.392.896.189.192.6106.4109.995.493.098.3
Percentage of RegulatedAndUnregulatedOperatingRevenue20.321.40.027.321.020.817.628.517.917.413.226.617.317.414.324.518.315.911.726.116.316.710.125.314.216.310.322.312.515.212.522.613.113.212.623.114.011.611.319.912.911.125.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:UtilityBusiness20.921.80.027.821.621.30.029.118.417.70.026.917.517.60.024.818.516.10.026.416.516.90.025.614.416.50.022.612.815.50.022.913.413.40.023.514.311.70.023.714.10.026.8

Other Comprehensive Income Loss Net Of Tax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax


Other
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-30
Value0-100000.0-2600000.0700000.0300000.00-1400000.0700000.01900000.0-300000.0600000.00-100000.00000000200000.0000-400000.0000600000.00
Percentage of OtherComprehensiveIncomeLossNetOfTax0.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.0100.00.00.00.00.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.0
Percentage of RegulatedAndUnregulatedOperatingRevenue0.0-0.0-0.30.10.00.0-0.20.10.2-0.00.10.0-0.00.00.00.00.00.00.00.00.00.00.00.0-0.00.00.00.00.10.0

us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Other
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value0-100000.0-2600000.0700000.0300000.00-1400000.0700000.01900000.0-300000.0600000.0
Percentage of OtherComprehensiveIncomeLossNetOfTax0.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue0.0-0.0-0.30.10.00.0-0.20.10.2-0.00.1
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.0

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense

us-gaap:OtherNonoperatingIncomeExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-2.0-2.0-7.0-3.0-2.5-1.9-3.4-3.7-3.3-4.0-1.6-1.6-2.0-2.40.10.20.10.10.20.10.00.20.30.10.20.10.00.2-0.11.7-1.30.60.30.81.60.70.61.12.00.70.80.83.10.6-0.50.8
Percentage of OtherNonoperatingIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue-0.2-0.20.0-0.3-0.3-0.2-0.4-0.4-0.4-0.4-0.2-0.2-0.2-0.30.00.00.00.00.00.00.00.00.00.00.00.00.00.0-0.00.2-0.20.10.00.10.20.10.10.10.20.10.10.10.40.1-0.10.1

us-gaap:OtherNonoperatingIncomeExpense dei:LegalEntity

lnt:Ipl


Other
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-2.0-5.0-1.0-1.0-0.9-1.5-2.0-1.5-1.9-0.6-0.5-0.7-0.80.00.10.2-0.10.20.00.10.00.2-0.10.00.1-2.40.00.10.00.10.00.10.10.00.00.00.20.1-0.10.00.20.30.2-0.3
Percentage of OtherNonoperatingIncomeExpense100.071.433.340.047.444.154.145.547.537.531.235.033.30.050.0200.0-100.0100.00.00.00.066.7-100.00.0100.00.00.0-100.00.0-7.70.033.312.50.00.00.018.25.0-14.30.025.09.733.360.0
Percentage of RegulatedAndUnregulatedOperatingRevenue-0.20.0-0.1-0.1-0.1-0.2-0.2-0.2-0.2-0.1-0.1-0.1-0.10.00.00.0-0.00.00.00.00.00.0-0.00.00.0-0.30.00.00.00.00.00.00.00.00.00.00.00.0-0.00.00.00.00.0-0.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl-0.40.0-0.2-0.2-0.2-0.3-0.3-0.3-0.3-0.1-0.1-0.1-0.20.00.00.0-0.00.00.00.00.00.1-0.00.00.0-0.60.00.00.00.00.00.00.00.00.00.00.10.0-0.00.00.00.10.0-0.1

lnt:Wpl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-06-302012-03-312011-06-302010-09-302010-06-30
Value0.0-1.00.0-1.0-0.8-0.5-1.4-1.4-1.6-1.6-1.7-1.3-1.0-1.1-0.10.10.00.10.0-0.10.20.10.10.30.1-0.10.9-0.5-0.30.00.10.0-0.10.1-0.10.10.0-0.10.1
Percentage of OtherNonoperatingIncomeExpense-0.050.0-0.033.332.026.341.237.848.540.0106.281.250.045.8-100.050.00.0100.00.0-100.00.050.033.3300.050.0-100.00.0-250.0300.00.0-7.70.0-33.312.5-16.79.10.0-16.7-20.0
Percentage of RegulatedAndUnregulatedOperatingRevenue0.0-0.10.0-0.1-0.1-0.1-0.2-0.1-0.2-0.2-0.2-0.1-0.1-0.1-0.00.00.00.00.0-0.00.00.00.00.00.0-0.00.1-0.1-0.00.00.00.0-0.00.0-0.00.00.0-0.00.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl0.0-0.30.0-0.3-0.3-0.1-0.4-0.4-0.5-0.4-0.5-0.4-0.3-0.3-0.00.00.00.00.0-0.00.10.00.00.10.0-0.00.3-0.1-0.10.00.00.0-0.00.0-0.00.00.0-0.00.0

Regulated And Unregulated Operating Revenue

us-gaap:RegulatedAndUnregulatedOperatingRevenue

us-gaap:RegulatedAndUnregulatedOperatingRevenue


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value8179018179207639158809907909878739288169168569067658537979247548437408987178978048437509528328667188597508876907658791021819945832951741890
Percentage of RegulatedAndUnregulatedOperatingRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RegulatedAndUnregulatedOperatingRevenue dei:LegalEntity

lnt:Ipl


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value455489443553431518496596441555494547474525472527420450434516411458398504382489431476411528463494383477393497360398404484374477417534389454
Percentage of RegulatedAndUnregulatedOperatingRevenue55.754.354.260.156.656.756.460.255.856.256.659.058.257.455.258.254.952.854.555.854.554.453.956.153.354.553.656.554.955.555.657.153.455.652.456.152.352.146.047.445.650.550.156.252.551.1
Percentage of RegulatedAndUnregulatedOperatingRevenue55.754.354.260.156.656.756.460.255.856.256.659.058.257.455.258.254.952.854.555.854.554.453.956.153.354.553.656.554.955.555.657.153.455.652.456.152.352.146.047.445.650.550.156.252.551.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value341395357351312375362372326415369370330381374370334393352397334375330382324397359354324410355360319369345376315354344374326388348369312392
Percentage of RegulatedAndUnregulatedOperatingRevenue41.743.843.738.240.941.041.237.641.342.142.339.940.541.743.840.843.746.044.242.944.344.544.742.645.344.344.742.043.243.142.741.644.643.046.042.445.746.339.236.739.941.141.838.842.244.1
Percentage of RegulatedAndUnregulatedOperatingRevenue41.743.843.738.240.941.041.237.641.342.142.339.940.541.743.840.843.746.044.242.944.344.544.742.645.344.344.742.043.243.142.741.644.643.046.042.445.746.339.236.739.941.141.838.842.244.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RegulatedAndUnregulatedOperatingRevenue dei:LegalEntity, us-gaap:StatementBusinessSegments

lnt:Ipl, lnt:Electric


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value402386363519388424408560392419394509422405381489372356360483364361333468339362328435354374354457329350300456321293311443323330317492
Percentage of RegulatedAndUnregulatedOperatingRevenue49.242.844.456.450.946.446.456.649.642.545.154.851.744.344.553.948.741.745.252.348.342.945.052.147.340.440.951.747.339.342.652.845.940.740.051.446.538.335.443.439.534.938.151.7
Percentage of RegulatedAndUnregulatedOperatingRevenue49.242.844.456.450.946.446.456.649.642.545.154.851.744.344.553.948.741.745.252.348.342.945.052.147.340.440.951.747.339.342.652.845.940.740.051.446.538.335.443.439.534.938.151.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Ipl, lnt:Gas


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value4391672433837624381248926421087827368361233484532329111882843135932442114772926927827381318628
Percentage of RegulatedAndUnregulatedOperatingRevenue5.310.18.22.64.49.18.72.54.912.610.22.95.211.89.23.04.89.77.72.64.610.07.22.64.212.411.03.45.814.211.22.85.813.310.33.33.912.18.92.74.714.010.43.0
Percentage of RegulatedAndUnregulatedOperatingRevenue5.310.18.22.64.49.18.72.54.912.610.22.95.211.89.23.04.89.77.72.64.610.07.22.64.212.411.03.45.814.211.22.85.813.310.33.33.912.18.92.74.714.010.43.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Ipl, lnt:OtherUtility


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value10.0121310.09.611121010101011101212111111129.112121212131514111319151211131511121214131115
Percentage of RegulatedAndUnregulatedOperatingRevenue1.21.31.61.11.31.21.41.11.31.11.21.31.31.31.41.21.51.31.61.01.61.51.71.41.81.71.81.41.82.01.91.41.61.62.01.31.91.71.71.41.41.6
Percentage of RegulatedAndUnregulatedOperatingRevenue1.21.31.61.11.31.21.41.11.31.11.21.31.31.31.41.21.51.31.61.01.61.51.71.41.81.71.81.41.82.01.91.41.61.62.01.31.91.71.71.41.41.6
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:OtherUtility100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:Electric


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value315315300333286305305355298323310352304303314351308321305381311307289367301308294335289301291340282283288358291279287353296290282349
Percentage of RegulatedAndUnregulatedOperatingRevenue38.635.036.736.237.633.434.735.937.832.835.537.937.333.136.738.840.337.638.441.241.336.439.240.842.034.436.639.838.631.735.039.339.332.938.440.442.236.532.734.636.230.733.936.7
Percentage of RegulatedAndUnregulatedOperatingRevenue38.635.036.736.237.633.434.735.937.832.835.537.937.333.136.738.840.337.638.441.241.336.439.240.842.034.436.639.838.631.735.039.339.332.938.440.442.236.532.734.636.230.733.936.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:Gas


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value26795318256956162691581826775918257145152268391421876418331056115318354172374561828976318
Percentage of RegulatedAndUnregulatedOperatingRevenue3.28.86.52.03.37.66.41.73.49.26.71.93.28.56.92.03.48.35.71.73.08.15.41.73.19.78.02.24.411.07.41.84.49.77.31.93.49.76.41.93.510.37.61.9
Percentage of RegulatedAndUnregulatedOperatingRevenue3.28.86.52.03.37.66.41.73.49.26.71.93.28.56.92.03.48.35.71.73.08.15.41.73.19.78.02.24.411.07.41.84.49.77.31.93.49.76.41.93.510.37.61.9
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:OtherUtility


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value0.01.04.00.00.50.51.10.40.40.41.00.60.21.21.00.20.40.51.00.30.30.31.00.51.81.21.40.62.03.83.25.26.03.81.70.70.90.91.42.01.81.3
Percentage of RegulatedAndUnregulatedOperatingRevenue0.00.10.50.00.10.10.10.00.10.00.10.10.00.10.10.00.10.10.10.00.00.00.10.10.30.10.20.10.30.40.40.60.80.40.20.10.10.10.20.20.20.1
Percentage of RegulatedAndUnregulatedOperatingRevenue0.00.10.50.00.10.10.10.00.10.00.10.10.00.10.10.00.10.10.10.00.00.00.10.10.30.10.20.10.30.40.40.60.80.40.20.10.10.10.20.20.20.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:OtherUtility0.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RegulatedAndUnregulatedOperatingRevenue us-gaap:PublicUtilityRegulatedOrUnregulatedStatus, us-gaap:StatementBusinessSegments

us-gaap:UnregulatedOperation, us-gaap:AllOtherSegments


Regulated
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-03-31
Value211716182121221610108.89.31010119.39.511101112131311141113131211
Percentage of RegulatedAndUnregulatedOperatingRevenue2.61.91.72.52.42.22.91.71.11.31.01.01.31.21.21.21.11.31.41.31.51.91.41.32.01.41.52.01.61.2
Percentage of RegulatedAndUnregulatedOperatingRevenue2.61.91.72.52.42.22.91.71.11.31.01.01.31.21.21.21.11.31.41.31.51.91.41.32.01.41.52.01.61.2
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:UnregulatedOperation us-gaap:AllOtherSegments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RegulatedAndUnregulatedOperatingRevenue us-gaap:StatementBusinessSegments

lnt:Electric


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value717701663852675730713915691743704861726708695840680677666864675668623835640671622771643675645798612633589815612572598796620600842
Percentage of RegulatedAndUnregulatedOperatingRevenue87.877.881.292.688.579.881.192.587.575.380.692.789.077.381.392.789.079.483.693.589.679.384.293.089.374.877.491.585.870.977.592.185.373.778.491.988.774.868.078.065.672.188.5
Percentage of RegulatedAndUnregulatedOperatingRevenue87.877.881.292.688.579.881.192.587.575.380.692.789.077.381.392.789.079.483.693.589.679.384.293.089.374.877.491.585.870.977.592.185.373.778.491.988.774.868.078.065.672.188.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Gas


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value69170120425815213241652151474468185138456215410639571529338511981524776240154397319713246501671344622914946
Percentage of RegulatedAndUnregulatedOperatingRevenue8.418.914.74.67.716.615.14.28.321.916.94.88.420.316.15.18.218.113.44.37.618.012.64.27.222.119.05.610.225.318.54.610.223.017.65.37.221.815.34.524.218.04.9
Percentage of RegulatedAndUnregulatedOperatingRevenue8.418.914.74.67.716.615.14.28.321.916.94.88.420.316.15.18.218.113.44.37.618.012.64.27.222.119.05.610.225.318.54.610.223.017.65.37.221.815.34.524.218.04.9
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:OtherUtility


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value10.0131710.01011131110111112101313111111139.41213131314161512152218171717171213131615161515
Percentage of RegulatedAndUnregulatedOperatingRevenue1.21.42.11.11.31.31.51.11.41.11.41.31.31.41.51.21.51.41.71.01.61.61.81.52.11.81.91.42.12.42.32.02.52.02.31.42.01.81.81.51.81.91.7
Percentage of RegulatedAndUnregulatedOperatingRevenue1.21.42.11.11.31.31.51.11.41.11.41.31.31.41.51.21.51.41.71.01.61.61.81.52.11.81.91.42.12.42.32.02.52.02.31.42.01.81.81.51.81.91.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:OtherUtility100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:UtilityBusiness


Regulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value796884800904744894859968767970863918805907846897755843786913745834729887706886790830736939818855703847738874676753748859866765904
Percentage of RegulatedAndUnregulatedOperatingRevenue97.498.197.998.397.597.697.697.897.198.398.998.998.799.098.999.098.798.898.798.898.898.998.698.798.698.798.498.598.198.698.398.798.098.698.398.598.098.485.184.191.691.995.0
Percentage of RegulatedAndUnregulatedOperatingRevenue97.498.197.998.397.597.697.697.897.198.398.998.998.799.098.999.098.798.898.798.898.898.998.698.798.698.798.498.598.198.698.398.798.098.698.398.598.098.485.184.191.691.995.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:UtilityBusiness100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Revenue From Contract With Customer Excluding Assessed Tax

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value8179018179207639158809907909878739288169168569067658537979247548437408987178978048437509528328667188597508876907658791021819945832951741890
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax dei:LegalEntity

lnt:Ipl


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value455489443553431518496596441555494547474525472527420450434516411458398504382489431476411528463494383477393497360398404484374477417534389454
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax55.754.354.260.156.656.756.460.255.856.256.659.058.257.455.258.254.952.854.555.854.554.453.956.153.354.553.656.554.955.555.657.153.455.652.456.152.352.146.047.445.650.550.156.252.551.1
Percentage of RegulatedAndUnregulatedOperatingRevenue55.754.354.260.156.656.756.460.255.856.256.659.058.257.455.258.254.952.854.555.854.554.453.956.153.354.553.656.554.955.555.657.153.455.652.456.152.352.146.047.445.650.550.156.252.551.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value341395357351312375362372326415369370330381374370334393352397334375330382324397359354324410355360319369345376315354344374326388348369312392
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax41.743.843.738.240.941.041.237.641.342.142.339.940.541.743.840.843.746.044.242.944.344.544.742.645.344.344.742.043.243.142.741.644.643.046.042.445.746.339.236.739.941.141.838.842.244.1
Percentage of RegulatedAndUnregulatedOperatingRevenue41.743.843.738.240.941.041.237.641.342.142.339.940.541.743.840.843.746.044.242.944.344.544.742.645.344.344.742.043.243.142.741.644.643.046.042.445.746.339.236.739.941.141.838.842.244.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax dei:LegalEntity, us-gaap:MajorCustomers, us-gaap:StatementBusinessSegments

lnt:Ipl, lnt:RetailCommercial, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value11511010314210911912315811111611514611411111213710399
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax14.112.212.615.414.313.114.016.014.111.813.215.714.012.213.115.213.511.7
Percentage of RegulatedAndUnregulatedOperatingRevenue14.112.212.615.414.313.114.016.014.111.813.215.714.012.213.115.213.511.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:RetailCommercial lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, lnt:RetailCommercial, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value1227216.08.324255.98.834266.41131237.81025
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.53.02.60.71.12.62.90.61.13.53.00.71.43.42.70.91.43.0
Percentage of RegulatedAndUnregulatedOperatingRevenue1.53.02.60.71.12.62.90.61.13.53.00.71.43.42.70.91.43.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:RetailCommercial lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, lnt:RetailIndustrial, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value116112104149114121112157118116115141128114109137109103
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax14.212.412.716.215.013.212.715.915.011.813.315.215.812.512.715.114.312.2
Percentage of RegulatedAndUnregulatedOperatingRevenue14.212.412.716.215.013.212.715.915.011.813.315.215.812.512.715.114.312.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:RetailIndustrial lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, lnt:RetailIndustrial, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value2.03.03.01.01.32.35.31.91.63.24.12.01.42.74.32.21.82.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.20.30.40.10.20.30.60.20.20.30.50.20.20.30.50.20.20.3
Percentage of RegulatedAndUnregulatedOperatingRevenue0.20.30.40.10.20.30.60.20.20.30.50.20.20.30.50.20.20.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:RetailIndustrial lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, lnt:RetailResidential, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value142139130189135147131196125147129180139142121168122123
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax17.415.415.920.517.716.115.019.815.914.914.819.417.115.514.218.616.014.4
Percentage of RegulatedAndUnregulatedOperatingRevenue17.415.415.920.517.716.115.019.815.914.914.819.417.115.514.218.616.014.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:RetailResidential lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, lnt:RetailResidential, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value245237121848391120775112226544121847
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.95.84.51.32.45.34.51.22.57.95.91.42.87.15.21.32.55.6
Percentage of RegulatedAndUnregulatedOperatingRevenue2.95.84.51.32.45.34.51.22.57.95.91.42.87.15.21.32.55.6
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:RetailResidential lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, lnt:Steam, lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value9.09.09.08.08.610.0109.19.28.48.78.78.49.49.38.38.48.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.11.01.10.91.11.11.20.91.20.91.00.91.01.01.10.91.11.0
Percentage of RegulatedAndUnregulatedOperatingRevenue1.11.01.10.91.11.11.20.91.20.91.00.91.01.01.10.91.11.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Steam lnt:OtherUtility0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, lnt:Wholesale, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value151113171314141714161418132424262321
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.81.21.61.81.71.61.71.81.81.71.72.01.72.72.82.93.02.5
Percentage of RegulatedAndUnregulatedOperatingRevenue1.81.21.61.81.71.61.71.81.81.71.72.01.72.72.82.93.02.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Wholesale lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, us-gaap:OtherCustomer, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value14141322162226312222192325
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.71.61.62.42.22.43.03.22.82.32.32.53.2
Percentage of RegulatedAndUnregulatedOperatingRevenue1.71.61.62.42.22.43.03.22.82.32.32.53.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl us-gaap:OtherCustomer lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, us-gaap:OtherCustomer, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value5.09.06.05.05.87.86.05.38.08.77.85.76.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.61.00.70.50.80.90.70.51.00.90.90.60.8
Percentage of RegulatedAndUnregulatedOperatingRevenue0.61.00.70.50.80.90.70.51.00.90.90.60.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl us-gaap:OtherCustomer lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, us-gaap:OtherCustomer, lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1.03.04.02.01.01.11.71.71.32.32.13.02.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.10.30.50.20.10.10.20.20.20.20.20.30.3
Percentage of RegulatedAndUnregulatedOperatingRevenue0.10.30.50.20.10.10.20.20.20.20.20.30.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl us-gaap:OtherCustomer lnt:OtherUtility0.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, lnt:RetailCommercial, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value606259685562637259645869586260686266
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax7.36.97.27.47.26.87.27.37.66.56.77.57.16.87.17.58.17.8
Percentage of RegulatedAndUnregulatedOperatingRevenue7.36.97.27.47.26.87.27.37.66.56.77.57.16.87.17.58.17.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:RetailCommercial lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, lnt:RetailCommercial, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value7.026164.06.421174.17.328194.67.525185.17.924
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.92.92.00.40.82.42.00.40.92.92.20.50.92.82.10.61.02.8
Percentage of RegulatedAndUnregulatedOperatingRevenue0.92.92.00.40.82.42.00.40.92.92.20.50.92.82.10.61.02.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:RetailCommercial lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, lnt:RetailIndustrial, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value949089928388901059592971069687971069891
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax11.510.010.910.010.99.710.310.712.19.411.211.511.89.511.411.712.810.7
Percentage of RegulatedAndUnregulatedOperatingRevenue11.510.010.910.010.99.710.310.712.19.411.211.511.89.511.411.712.810.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:RetailIndustrial lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, lnt:RetailIndustrial, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value1.02.01.01.00.41.91.00.40.42.2-0.61.01.23.12.00.80.82.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.10.20.10.10.10.20.10.00.10.2-0.10.10.10.30.20.10.10.2
Percentage of RegulatedAndUnregulatedOperatingRevenue0.10.20.10.10.10.20.10.00.10.2-0.10.10.10.30.20.10.10.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:RetailIndustrial lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, lnt:RetailResidential, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value116123118139114119120135107127113132109117117127106117
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax14.213.714.415.115.013.013.713.713.612.913.014.313.412.813.814.114.013.8
Percentage of RegulatedAndUnregulatedOperatingRevenue14.213.714.415.115.013.013.713.713.612.913.014.313.412.813.814.114.013.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:RetailResidential lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, lnt:RetailResidential, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value15473110.01541328.71553329.21445359.51442
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.85.23.81.12.04.63.70.91.95.53.81.01.84.94.11.01.94.9
Percentage of RegulatedAndUnregulatedOperatingRevenue1.85.23.81.12.04.63.70.91.95.53.81.01.84.94.11.01.94.9
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:RetailResidential lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, lnt:Wholesale, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value322928302626243226292631292927363642
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax3.93.23.43.33.42.92.83.23.33.03.13.43.63.23.34.14.74.9
Percentage of RegulatedAndUnregulatedOperatingRevenue3.93.23.43.33.42.92.83.23.33.03.13.43.63.23.34.14.74.9
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:Wholesale lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:OtherCustomer, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value13116.04.08.38.36.08.99.49.7121111
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.61.20.70.41.10.90.70.91.21.01.41.21.4
Percentage of RegulatedAndUnregulatedOperatingRevenue1.61.20.70.41.10.90.70.91.21.01.41.21.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl us-gaap:OtherCustomer lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:OtherCustomer, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3.04.05.03.03.14.05.33.53.96.37.03.32.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.40.40.60.30.40.40.60.40.50.60.80.40.3
Percentage of RegulatedAndUnregulatedOperatingRevenue0.40.40.60.30.40.40.60.40.50.60.80.40.3
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl us-gaap:OtherCustomer lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:OtherCustomer, lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value0.01.04.00.00.50.51.10.40.40.41.00.60.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.50.00.10.10.10.00.10.00.10.10.0
Percentage of RegulatedAndUnregulatedOperatingRevenue0.00.10.50.00.10.10.10.00.10.00.10.10.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl us-gaap:OtherCustomer lnt:OtherUtility0.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax dei:LegalEntity, us-gaap:StatementBusinessSegments

lnt:Ipl, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value402386363519388424408560392419394509422405381489372356360483364361333468339362328435354374354457329350300456321293311443323330317492
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax49.242.844.456.450.946.446.456.649.642.545.154.851.744.344.553.948.741.745.252.348.342.945.052.147.340.440.951.747.339.342.652.845.940.740.051.446.538.335.443.439.534.938.151.7
Percentage of RegulatedAndUnregulatedOperatingRevenue49.242.844.456.450.946.446.456.649.642.545.154.851.744.344.553.948.741.745.252.348.342.945.052.147.340.440.951.747.339.342.652.845.940.740.051.446.538.335.443.439.534.938.151.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Ipl, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value4391672433837624381248926421087827368361233484532329111882843135932442114772926927827381318628
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax5.310.18.22.64.49.18.72.54.912.610.22.95.211.89.23.04.89.77.72.64.610.07.22.64.212.411.03.45.814.211.22.85.813.310.33.33.912.18.92.74.714.010.43.0
Percentage of RegulatedAndUnregulatedOperatingRevenue5.310.18.22.64.49.18.72.54.912.610.22.95.211.89.23.04.89.77.72.64.610.07.22.64.212.411.03.45.814.211.22.85.813.310.33.33.912.18.92.74.714.010.43.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Ipl, lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value10.0121310.09.611121010101011101212111111129.112121212131514111319151211131511121214131115
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.21.31.61.11.31.21.41.11.31.11.21.31.31.31.41.21.51.31.61.01.61.51.71.41.81.71.81.41.82.01.91.41.61.62.01.31.91.71.71.41.41.6
Percentage of RegulatedAndUnregulatedOperatingRevenue1.21.31.61.11.31.21.41.11.31.11.21.31.31.31.41.21.51.31.61.01.61.51.71.41.81.71.81.41.82.01.91.41.61.62.01.31.91.71.71.41.41.6
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl lnt:OtherUtility100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value315315300333286305305355298323310352304303314351308321305381311307289367301308294335289301291340282283288358291279287353296290282349
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax38.635.036.736.237.633.434.735.937.832.835.537.937.333.136.738.840.337.638.441.241.336.439.240.842.034.436.639.838.631.735.039.339.332.938.440.442.236.532.734.636.230.733.936.7
Percentage of RegulatedAndUnregulatedOperatingRevenue38.635.036.736.237.633.434.735.937.832.835.537.937.333.136.738.840.337.638.441.241.336.439.240.842.034.436.639.838.631.735.039.339.332.938.440.442.236.532.734.636.230.733.936.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value26795318256956162691581826775918257145152268391421876418331056115318354172374561828976318
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax3.28.86.52.03.37.66.41.73.49.26.71.93.28.56.92.03.48.35.71.73.08.15.41.73.19.78.02.24.411.07.41.84.49.77.31.93.49.76.41.93.510.37.61.9
Percentage of RegulatedAndUnregulatedOperatingRevenue3.28.86.52.03.37.66.41.73.49.26.71.93.28.56.92.03.48.35.71.73.08.15.41.73.19.78.02.24.411.07.41.84.49.77.31.93.49.76.41.93.510.37.61.9
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value0.01.04.00.00.50.51.10.40.40.41.00.60.21.21.00.20.40.51.00.30.30.31.00.51.81.21.40.62.03.83.25.26.03.81.70.70.90.91.42.01.81.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.50.00.10.10.10.00.10.00.10.10.00.10.10.00.10.10.10.00.00.00.10.10.30.10.20.10.30.40.40.60.80.40.20.10.10.10.20.20.20.1
Percentage of RegulatedAndUnregulatedOperatingRevenue0.00.10.50.00.10.10.10.00.10.00.10.10.00.10.10.00.10.10.10.00.00.00.10.10.30.10.20.10.30.40.40.60.80.40.20.10.10.10.20.20.20.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl lnt:OtherUtility0.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:MajorCustomers, us-gaap:StatementBusinessSegments

lnt:RetailCommercial, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value175172162210164182186230171181173215172174173205165165
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax21.419.119.822.821.519.921.223.321.718.319.923.221.119.020.222.721.719.4
Percentage of RegulatedAndUnregulatedOperatingRevenue21.419.119.822.821.519.921.223.321.718.319.923.221.119.020.222.721.719.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:RetailCommercial lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:RetailCommercial, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value19533710.014454310.016634511195741121849
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.35.94.51.11.95.04.91.02.06.45.21.22.46.24.91.42.45.8
Percentage of RegulatedAndUnregulatedOperatingRevenue2.35.94.51.11.95.04.91.02.06.45.21.22.46.24.91.42.45.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:RetailCommercial lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:RetailIndustrial, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value210202193241197209202263214208213247225201206243207195
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax25.722.423.626.225.922.923.026.627.121.124.526.727.622.024.226.827.222.8
Percentage of RegulatedAndUnregulatedOperatingRevenue25.722.423.626.225.922.923.026.627.121.124.526.727.622.024.226.827.222.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:RetailIndustrial lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:RetailIndustrial, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value3.05.04.02.01.74.26.32.32.05.43.53.02.65.86.33.02.64.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.40.60.50.20.20.50.70.20.30.50.40.30.30.60.70.30.30.6
Percentage of RegulatedAndUnregulatedOperatingRevenue0.40.60.50.20.20.50.70.20.30.50.40.30.30.60.70.30.30.6
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:RetailIndustrial lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:RetailResidential, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value258262248328249266252331233274242312248259239296229241
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax31.629.130.435.732.729.128.733.529.527.827.833.730.428.328.032.730.028.2
Percentage of RegulatedAndUnregulatedOperatingRevenue31.629.130.435.732.729.128.733.529.527.827.833.730.428.328.032.730.028.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:RetailResidential lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:RetailResidential, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value39996822339071203513184213711079213389
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax4.811.08.32.44.49.98.12.14.513.49.72.34.612.19.32.44.410.5
Percentage of RegulatedAndUnregulatedOperatingRevenue4.811.08.32.44.49.98.12.14.513.49.72.34.612.19.32.44.410.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:RetailResidential lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Steam, lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value9.09.09.08.08.610.0109.19.28.48.78.78.49.49.38.38.48.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.11.01.10.91.11.11.20.91.20.91.00.91.01.01.10.91.11.0
Percentage of RegulatedAndUnregulatedOperatingRevenue1.11.01.10.91.11.11.20.91.20.91.00.91.01.01.10.91.11.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Steam lnt:OtherUtility0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:TransportationandOther, us-gaap:AllOtherSegments


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value211716182121221610108.89.31010
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.61.91.72.52.42.22.91.71.11.31.01.01.31.2
Percentage of RegulatedAndUnregulatedOperatingRevenue2.61.91.72.52.42.22.91.71.11.31.01.01.31.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:TransportationandOther us-gaap:AllOtherSegments0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wholesale, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value474041473940394941464150435352635963
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax5.84.45.05.15.14.54.55.05.24.74.85.45.35.96.17.07.87.4
Percentage of RegulatedAndUnregulatedOperatingRevenue5.84.45.05.15.14.54.55.05.24.74.85.45.35.96.17.07.87.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wholesale lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherCustomer, lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value27251926253032403132323537
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax3.32.82.32.83.33.33.64.14.03.33.73.84.6
Percentage of RegulatedAndUnregulatedOperatingRevenue3.32.82.32.83.33.33.64.14.03.33.73.84.6
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:OtherCustomer lnt:Electric0.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherCustomer, lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value8.013118.08.911118.81115149.09.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.01.41.30.91.21.31.30.91.51.51.71.01.1
Percentage of RegulatedAndUnregulatedOperatingRevenue1.01.41.30.91.21.31.30.91.51.51.71.01.1
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:OtherCustomer lnt:Gas0.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherCustomer, lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1.04.08.02.01.51.62.82.11.72.73.13.62.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.10.41.00.20.20.20.30.20.20.30.40.40.3
Percentage of RegulatedAndUnregulatedOperatingRevenue0.10.41.00.20.20.20.30.20.20.30.40.40.3
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:OtherCustomer lnt:OtherUtility0.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementBusinessSegments

lnt:Electric


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value717701663852675730713915691743704861726708695840680677666864675668623835640671622771643675645798612633589815612572598796620600842
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax87.877.881.292.688.579.881.192.587.575.380.692.789.077.381.392.789.079.483.693.589.679.384.293.089.374.877.491.585.870.977.592.185.373.778.491.988.774.868.078.065.672.188.5
Percentage of RegulatedAndUnregulatedOperatingRevenue87.877.881.292.688.579.881.192.587.575.380.692.789.077.381.392.789.079.483.693.589.679.384.293.089.374.877.491.585.870.977.592.185.373.778.491.988.774.868.078.065.672.188.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Gas


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value69170120425815213241652151474468185138456215410639571529338511981524776240154397319713246501671344622914946
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax8.418.914.74.67.716.615.14.28.321.916.94.88.420.316.15.18.218.113.44.37.618.012.64.27.222.119.05.610.225.318.54.610.223.017.65.37.221.815.34.524.218.04.9
Percentage of RegulatedAndUnregulatedOperatingRevenue8.418.914.74.67.716.615.14.28.321.916.94.88.420.316.15.18.218.113.44.37.618.012.64.27.222.119.05.610.225.318.54.610.223.017.65.37.221.815.34.524.218.04.9
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:OtherUtility


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-03-312010-12-312010-09-30
Value10.0131710.01011131110111112101313111111139.41213131314161512152218171717171213131615161515
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.21.42.11.11.31.31.51.11.41.11.41.31.31.41.51.21.51.41.71.01.61.61.81.52.11.81.91.42.12.42.32.02.52.02.31.42.01.81.81.51.81.91.7
Percentage of RegulatedAndUnregulatedOperatingRevenue1.21.42.11.11.31.31.51.11.41.11.41.31.31.41.51.21.51.41.71.01.61.61.81.52.11.81.91.42.12.42.32.02.52.02.31.42.01.81.81.51.81.91.7
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:OtherUtility100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AllOtherSegments


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value2117171618212121221610.010108.89.29.31010
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.61.92.11.72.52.42.42.22.91.71.11.11.31.01.11.01.31.2
Percentage of RegulatedAndUnregulatedOperatingRevenue2.61.92.11.72.52.42.42.22.91.71.11.11.31.01.11.01.31.2
Percentage of RegulatedAndUnregulatedOperatingRevenue us-gaap:AllOtherSegments0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Revenues

us-gaap:Revenues

us-gaap:Revenues


Revenues
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value8179018179207639158809907909878739288169168569067658537979247548437408987178978048437509528328667188597508876907658791021819945832951741890
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Unregulated Operating Revenue

us-gaap:UnregulatedOperatingRevenue

us-gaap:UnregulatedOperatingRevenue


Unregulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value2117171618212121221610.010108.89.29.3101010119.39.5101110111312131313111411121313121301621187967473942
Percentage of UnregulatedOperatingRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue2.61.92.11.72.52.42.42.22.91.71.11.11.31.01.11.01.31.21.31.21.21.11.41.31.41.31.61.51.91.41.71.32.01.41.71.52.01.614.915.914.58.48.15.05.34.8

Assets

us-gaap:Assets

us-gaap:Assets


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value17939175941771017540172691687916700165331612115713154261526914615142411418714114137431346413373130291268512535124951255812312120791208511594113861111611112109811088710733107851025099349628968794819301940092829036
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets dei:LegalEntity

lnt:Ipl


Assetsdei:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value9825972698499858967994049277930288308647841183787849762776067682750773237304716167966713670967796587641464616194600058305806569356115530545753995201506650934960488649374892
Percentage of Assets54.855.355.656.256.055.755.656.354.855.054.554.953.753.653.654.454.654.454.655.053.653.653.754.053.553.153.553.452.752.452.251.951.551.550.652.752.452.652.652.352.553.254.1
Percentage of Assets54.855.355.656.256.055.755.656.354.855.054.554.953.753.653.654.454.654.454.655.053.653.653.754.053.553.153.553.452.752.452.251.951.551.550.652.752.452.652.652.352.553.254.1
Percentage of Assets lnt:Ipl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl


Assetsdei:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value7117691069126744664865516506631363906165615260445910575757565594545653355290540553465305527052635202516651284906488548134804481647824717476242574156405840443936387438893681
Percentage of Assets39.739.339.038.438.538.839.038.239.639.239.939.640.440.440.639.639.739.639.641.542.142.342.241.942.342.842.442.342.943.343.243.943.943.944.241.541.842.241.741.541.741.940.7
Percentage of Assets39.739.339.038.438.538.839.038.239.639.239.939.640.440.440.639.639.739.639.641.542.142.342.241.942.342.842.442.342.943.343.243.943.943.944.241.541.842.241.741.541.741.940.7
Percentage of Assets lnt:Wpl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets dei:LegalEntity, us-gaap:StatementBusinessSegments

lnt:Ipl, lnt:Electric


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value851880757219652462785754539849054500420840253976
Percentage of Assets48.148.446.846.046.946.144.744.141.743.443.444.0
Percentage of Assets48.148.446.846.046.946.144.744.141.743.443.444.0
Percentage of Assets lnt:Ipl lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Ipl, lnt:Gas


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value766734687727653548544518479471460461
Percentage of Assets4.34.44.55.14.94.44.54.74.44.95.05.1
Percentage of Assets4.34.44.55.14.94.44.54.74.44.95.05.1
Percentage of Assets lnt:Ipl lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Ipl, lnt:OtherUtility


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value565469504353373406519381476414452454
Percentage of Assets3.22.83.32.52.83.34.33.44.44.34.95.0
Percentage of Assets3.22.83.32.52.83.34.33.44.44.34.95.0
Percentage of Assets lnt:Ipl lnt:OtherUtility100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Ipl, lnt:UtilityBusiness


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value98499277841176067304670964615806545750934937
Percentage of Assets55.655.654.553.654.653.753.552.250.652.653.2
Percentage of Assets55.655.654.553.654.653.753.552.250.652.653.2
Percentage of Assets lnt:Ipl lnt:UtilityBusiness100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:Electric


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value584055845266487144444457426241133937331632012891
Percentage of Assets33.033.434.134.333.235.735.337.036.534.234.532.0
Percentage of Assets33.033.434.134.333.235.735.337.036.534.234.532.0
Percentage of Assets lnt:Wpl lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:Gas


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value647535496471437391369340335360357341
Percentage of Assets3.73.23.23.33.33.13.13.13.13.73.83.8
Percentage of Assets3.73.23.23.33.33.13.13.13.13.73.83.8
Percentage of Assets lnt:Wpl lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:OtherUtility


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value425387389412407422496350489366330
Percentage of Assets2.42.32.52.93.03.44.13.24.53.83.6
Percentage of Assets2.42.32.52.93.03.44.13.24.53.83.6
Percentage of Assets lnt:Wpl lnt:OtherUtility100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl, lnt:UtilityBusiness


Assetsdei:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value69126506615257565290527051284804476240443889
Percentage of Assets39.039.039.940.639.642.242.443.244.241.741.9
Percentage of Assets39.039.039.940.639.642.242.443.244.241.741.9
Percentage of Assets lnt:Wpl lnt:UtilityBusiness100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets us-gaap:ConsolidatedEntities

srt:ParentCompany


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-31
Value679161405627
Percentage of Assets38.336.836.5
Percentage of Assets38.336.836.5
Percentage of Assets srt:ParentCompany100.0100.0100.0

us-gaap:Assets us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:UnregulatedOperation


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value949916862825461515495502565550455
Percentage of Assets5.45.55.65.83.44.14.14.55.25.74.9
Percentage of Assets5.45.55.65.83.44.14.14.55.25.74.9
Percentage of Assets us-gaap:UnregulatedOperation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets us-gaap:StatementBusinessSegments

lnt:Electric


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value143581365912486113961104010211966090188438752472276867
Percentage of Assets81.181.880.980.382.681.779.981.278.277.777.976.0
Percentage of Assets81.181.880.980.382.681.779.981.278.277.777.976.0
Percentage of Assets lnt:Electric100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Gas


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value14131269118411991091939913859814831817803
Percentage of Assets8.07.67.78.58.27.57.67.77.68.68.88.9
Percentage of Assets8.07.67.78.58.27.57.67.77.68.68.88.9
Percentage of Assets lnt:Gas100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:OtherUtility


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value9908568937667818281016732966781782902
Percentage of Assets5.65.15.85.45.86.68.46.69.08.18.410.0
Percentage of Assets5.65.15.85.45.86.68.46.69.08.18.410.0
Percentage of Assets lnt:OtherUtility100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:UtilityBusiness


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-31
Value167611578414563133621291211979115901061010219913788278573
Percentage of Assets94.694.594.494.296.695.995.995.594.894.395.194.9
Percentage of Assets94.694.594.494.296.695.995.995.594.894.395.194.9
Percentage of Assets lnt:UtilityBusiness100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:LiabilitiesAndStockholdersEquity


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value17939175941771017540172691687916700165331612115713154261526914615142411418714114137431346413373130291268512535124951255812312120791208511594113861111611112109811088710733107851025099349628968794819301940092829036
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilitiesAndStockholdersEquity dei:LegalEntity

lnt:Ipl


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value982597269849985896799404927793028830864784118378784976277606768275077323730471616796671367096779658764146461619460005830580656935611553054575399520150665093496048864937
Percentage of LiabilitiesAndStockholdersEquity54.855.355.656.256.055.755.656.354.855.054.554.953.753.653.654.454.654.454.655.053.653.653.754.053.553.153.553.452.752.452.251.951.551.550.652.752.452.652.652.352.553.2
Percentage of Assets54.855.355.656.256.055.755.656.354.855.054.554.953.753.653.654.454.654.454.655.053.653.653.754.053.553.153.553.452.752.452.251.951.551.550.652.752.452.652.652.352.553.2
Percentage of Assets lnt:Ipl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

lnt:Wpl


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value711769106912674466486551650663136390616561526044591057575756559454565335529054055346530552705263520251665128490648854813480448164782471747624257415640584044393638743889
Percentage of LiabilitiesAndStockholdersEquity39.739.339.038.438.538.839.038.239.639.239.939.640.440.440.639.639.739.639.641.542.142.342.241.942.342.842.442.342.943.343.243.943.943.944.241.541.842.241.741.541.741.9
Percentage of Assets39.739.339.038.438.538.839.038.239.639.239.939.640.440.440.639.639.739.639.641.542.142.342.241.942.342.842.442.342.943.343.243.943.943.944.241.541.842.241.741.541.741.9
Percentage of Assets lnt:Wpl100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilitiesAndStockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilities
Period End2020-12-312019-12-312018-12-31
Value679161405627
Percentage of LiabilitiesAndStockholdersEquity38.336.836.5
Percentage of Assets38.336.836.5
Percentage of Assets srt:ParentCompany100.0100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-312007-12-31
Value5819576656885709554855025205496946994682458545704350423141824154405038963862385937903764372437453620359734383435333733313281326631603145313431163014299730133001292729202893277228232681
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets32.432.832.132.532.132.631.230.129.229.829.729.929.829.729.529.429.528.928.929.629.930.029.829.829.429.828.529.629.330.029.529.729.029.329.130.430.331.131.131.731.531.131.230.70.00.0

us-gaap:StockholdersEquity dei:LegalEntity

lnt:Ipl


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-312008-12-31
Value37793742376437303471339532713244314531423030283826542514250924322351224722492137203620421995199119081826181418291731171816791663155515351519149813951360139413631294138913301148
Percentage of StockholdersEquity64.964.966.265.362.661.762.965.366.967.166.162.161.059.460.058.658.057.758.255.453.754.353.653.252.750.852.853.251.951.651.250.949.248.848.548.146.345.446.345.444.248.048.040.7
Percentage of Assets21.121.321.321.320.120.119.619.619.520.019.618.618.217.717.717.217.116.716.816.416.116.316.015.915.515.115.015.815.215.515.115.214.314.314.114.614.014.114.414.413.915.014.70.0
Percentage of Assets lnt:Ipl38.538.538.237.835.936.135.334.935.636.336.033.933.833.033.031.731.330.730.829.930.030.429.729.429.028.528.129.528.929.528.929.227.727.827.827.726.826.827.427.526.528.127.20.0

lnt:Wpl


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-312008-12-31
Value27252645247824822451243623632324218521792149214620551900188118091751174417301813177817691756175917231716170317041672166716421633160115951583148014521445144214291406136912541159
Percentage of StockholdersEquity46.845.943.643.544.244.345.446.846.546.546.947.047.244.945.043.643.244.844.847.046.947.047.247.047.647.749.549.650.150.150.150.050.750.750.547.548.248.247.947.648.047.345.341.1
Percentage of Assets15.215.014.014.214.214.414.214.113.613.913.914.114.113.313.312.812.713.012.913.914.014.114.114.014.014.214.114.714.715.014.814.914.714.914.714.414.615.014.915.115.114.813.90.0
Percentage of Assets lnt:Wpl38.338.335.936.836.937.236.336.834.235.334.935.534.833.032.732.432.132.732.733.633.333.333.333.433.133.233.234.734.234.634.233.933.533.833.234.835.035.635.736.336.335.234.10.0

us-gaap:StockholdersEquity dei:LegalEntity, us-gaap:StatementEquityComponents

lnt:Ipl, us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value280227522752269325222447234723222322232222222027192717971797159714071242115210379279741042998
Percentage of StockholdersEquity48.247.748.447.245.544.545.146.749.449.648.544.444.342.543.041.437.836.135.133.130.833.737.635.3
Percentage of Assets15.615.615.515.414.614.514.114.014.414.814.413.313.212.612.711.911.310.310.49.69.610.511.50.0
Percentage of Assets lnt:Ipl us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value333333333333333333333333333333333333333333333333
Percentage of StockholdersEquity0.60.60.60.60.60.60.60.70.70.70.70.70.80.80.80.90.91.01.01.11.11.21.21.2
Percentage of Assets0.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.30.30.30.30.30.40.40.0
Percentage of Assets lnt:Ipl us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value9449579791004914914890887788785774777692683678617554537493448433382254116
Percentage of StockholdersEquity16.216.617.217.616.516.617.117.916.816.816.917.015.916.116.216.014.915.615.014.314.413.29.24.1
Percentage of Assets5.35.45.55.75.35.45.35.44.95.05.05.14.74.84.84.64.44.54.44.24.54.12.80.0
Percentage of Assets lnt:Ipl us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value1669158414591459145914591434140913091309130913091259110911091019959959959959869844768668
Percentage of StockholdersEquity28.727.525.725.626.326.527.528.427.928.028.528.628.926.226.526.425.827.929.230.628.829.227.723.7
Percentage of Assets9.39.08.28.38.48.68.68.58.18.38.58.68.67.87.87.67.77.98.68.99.09.18.50.0
Percentage of Assets lnt:Wpl us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value666666666666666666666666666666666666666666666666
Percentage of StockholdersEquity1.11.11.21.21.21.21.31.31.41.41.41.41.51.61.61.71.81.92.02.12.22.32.42.3
Percentage of Assets0.40.40.40.40.40.40.40.40.40.40.40.40.50.50.50.50.50.50.60.60.70.70.70.0
Percentage of Assets lnt:Wpl us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value990995953957926910863849810804774771730725706645731678617557507459419424
Percentage of StockholdersEquity17.017.316.816.816.716.616.617.117.217.216.916.916.817.116.916.719.619.718.817.816.815.915.115.0
Percentage of Assets5.55.75.45.55.45.45.25.15.05.15.05.15.05.15.04.85.95.65.65.25.24.94.60.0
Percentage of Assets lnt:Wpl us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-31
Value569152064585
Percentage of StockholdersEquity100.1100.0100.0
Percentage of Assets32.131.229.7
Percentage of Assets srt:ParentCompany83.884.881.5

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-1.0-1.0-1.0-1.0-0.62.01.31.01.02.41.7-0.20.1-0.5-0.5-0.4-0.4-0.6-0.2-0.8-0.8-1.4-1.4-1.40.2
Percentage of StockholdersEquity-0.0-0.0-0.0-0.0-0.00.00.00.00.00.10.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.00.0
Percentage of Assets-0.0-0.0-0.0-0.0-0.00.00.00.00.00.00.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.00.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value2722271227042693268326742445223621082100204520381947185118451693166315091507151115101506149914941483
Percentage of StockholdersEquity46.847.047.547.248.448.647.045.044.944.844.644.644.843.844.143.844.743.945.948.250.152.154.152.955.3
Percentage of Assets15.215.415.315.415.515.814.613.513.113.413.313.313.313.013.012.713.312.513.614.015.616.216.60.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value3.03.02.02.02.52.52.52.42.42.42.42.42.32.32.32.31.11.11.11.11.11.11.11.11.1
Percentage of StockholdersEquity0.10.10.00.00.00.00.00.00.10.10.10.10.10.10.10.10.00.00.00.00.00.00.00.00.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:DeferredCompensationShareBasedPayments


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-11.0-11.0-11.0-11.0-10.2-9.9-10.0-10.2-10.0-9.7-9.8-9.5-11.4-11.1-11.1-10.0-8.5-8.9-8.0-7.3-8.3-7.6-7.9-7.3-8.7
Percentage of StockholdersEquity-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.3-0.3-0.3-0.3-0.2-0.3-0.2-0.2-0.3-0.3-0.3-0.3-0.3
Percentage of Assets-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.10.00.0
Percentage of Assets us-gaap:DeferredCompensationShareBasedPayments0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value3106306329943026287328332765273925972587254525392412238923462177206819381780163015101394128113361205
Percentage of StockholdersEquity53.453.152.653.051.851.553.155.155.355.355.555.655.556.556.156.455.656.454.352.050.148.246.247.345.0
Percentage of Assets17.317.416.917.316.616.816.616.616.116.516.516.616.516.816.516.316.616.016.015.115.615.014.20.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets Current

us-gaap:AssetsCurrent

us-gaap:AssetsCurrent


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value8997558871033104491287511131027815785112480572590575181474987795870276882610871043913104396210109361011880893870994102892078086694787797710921390
Percentage of AssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets5.04.35.05.96.05.45.26.76.45.25.17.45.55.16.45.35.95.66.67.45.56.16.68.78.57.68.68.38.98.49.18.08.28.19.210.09.38.18.910.09.410.411.815.4

us-gaap:AssetsCurrent dei:LegalEntity

lnt:Ipl


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value455393496638624435409621399355371715430330476357379330422534275338396601542418556527546497535449431417391467374289323341323428
Percentage of AssetsCurrent50.652.155.961.859.847.846.855.838.943.647.463.653.445.552.647.546.644.048.255.739.244.047.955.352.045.853.354.854.153.153.051.148.248.039.445.440.737.037.336.036.939.2
Percentage of Assets2.52.22.83.63.62.62.53.82.52.32.44.72.92.33.42.52.82.53.24.12.22.73.24.84.43.54.64.54.84.54.84.14.03.93.64.63.83.03.33.63.54.6
Percentage of Assets lnt:Ipl4.64.05.06.56.54.64.46.74.54.14.48.55.54.36.34.75.14.55.87.54.05.05.98.98.26.58.68.59.18.59.27.97.77.67.28.77.25.76.36.96.68.7

lnt:Wpl


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value383330362338356435442450593416384400351369418385382368416377380410423453454466457389401400402388395398468454433379386393367445
Percentage of AssetsCurrent42.643.740.832.734.147.850.640.457.751.049.035.643.650.946.251.346.949.147.539.354.153.551.241.743.551.143.840.539.842.839.844.144.345.747.144.247.148.744.541.541.840.7
Percentage of Assets2.11.92.01.92.12.62.72.73.72.62.52.62.42.63.02.72.82.73.12.93.03.33.43.63.73.93.83.43.53.63.63.53.63.74.34.44.43.94.04.13.94.8
Percentage of Assets lnt:Wpl5.44.85.25.05.46.66.87.19.36.76.36.66.06.47.36.97.06.97.97.07.17.78.08.68.79.08.97.98.28.38.48.18.38.49.810.710.49.49.510.09.511.4

us-gaap:AssetsCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Assets
Period End2020-12-312019-12-312018-12-31
Value373327
Percentage of AssetsCurrent4.23.83.4
Percentage of Assets0.20.20.2
Percentage of Assets srt:ParentCompany0.50.50.5

us-gaap:AssetsCurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assets
Period End2020-12-312019-12-31
Value121139
Percentage of AssetsCurrent13.615.9
Percentage of Assets0.70.8
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees0.00.0

Cash And Cash Equivalents At Carrying Value

us-gaap:CashAndCashEquivalentsAtCarryingValue

us-gaap:CashAndCashEquivalentsAtCarryingValue


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312008-12-312007-12-31
Value151454189208551619317010202395.019279.27.38.48.2846.54.85.81395497561116149.817115321413030114577126159137171140175346745
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.31.11.20.30.11.21.10.10.11.60.00.10.20.10.10.10.10.70.10.00.01.10.40.80.50.10.10.10.10.20.10.50.20.40.30.30.10.50.81.31.70.00.00.01.90.00.0

us-gaap:CashAndCashEquivalentsAtCarryingValue dei:LegalEntity

lnt:Ipl


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value111150185203259.31845.03.99.72321.62.93.64.74.04.13.3772.43.04.5992.02.65.34.65.45.84.46.35.14.74.55.32.8232.10.2213.95.72.6280.46.2
Percentage of CashAndCashEquivalentsAtCarryingValue73.378.692.697.997.845.357.195.02.938.646.497.132.015.212.951.154.848.840.291.736.962.577.671.43.62.79.341.833.340.044.935.644.38.821.212.99.174.818.40.427.23.13.61.916.70.21.8
Percentage of Assets0.10.10.31.11.20.10.11.10.00.00.11.50.00.00.00.00.00.00.00.60.00.00.00.80.00.00.00.00.00.10.00.10.00.00.00.10.00.20.00.00.20.00.10.00.00.00.0
Percentage of Assets lnt:Ipl0.10.10.51.92.10.30.12.00.10.00.12.80.00.00.00.10.10.10.01.10.00.00.11.50.00.00.10.10.10.10.10.10.10.10.10.10.10.50.00.00.40.00.10.00.00.00.0

lnt:Wpl


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-312008-12-31
Value3.02.03.02.03.2224.48.31633.48.76.42.53.7233.22.82.14.25.63.11.30.4354890462.36.44.90.56.62.58.40.7162.52.12.723131.00.13527184.5
Percentage of CashAndCashEquivalentsAtCarryingValue20.014.35.61.11.541.127.04.395.933.741.62.750.019.482.834.838.425.051.26.647.727.16.925.689.193.182.120.939.533.85.137.321.715.73.339.48.16.823.751.417.10.80.125.916.210.61.3
Percentage of Assets0.00.00.00.00.00.10.00.11.00.00.10.00.00.00.20.00.00.00.00.00.00.00.00.30.40.80.40.00.10.00.00.10.00.10.00.20.00.00.00.20.10.00.00.00.00.20.0
Percentage of Assets lnt:Wpl0.00.00.00.00.00.30.10.12.60.10.10.10.00.10.40.10.10.00.10.10.10.00.00.70.91.80.90.00.10.10.00.10.10.20.00.40.10.10.10.60.30.00.00.00.00.50.0

Accounts Receivable Net Current

us-gaap:AccountsReceivableNetCurrent

us-gaap:AccountsReceivableNetCurrent


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value37732541239938639640245142141735046541534348233642442449349131639039742729736142784851068178859894938192188198127140120246
Percentage of AccountsReceivableNetCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.11.82.32.32.22.32.42.72.62.72.33.02.82.43.42.43.13.23.73.82.53.13.23.42.43.03.50.70.81.00.70.70.80.90.90.90.81.01.92.11.41.51.32.7

us-gaap:AccountsReceivableNetCurrent dei:LegalEntity

lnt:Ipl


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1821302102192082042022582312091532772371452641431941772402669718020023510415821620024225724613011516595183102517510883174
Percentage of AccountsReceivableNetCurrent48.340.051.054.954.051.750.457.255.050.143.859.657.242.554.942.745.841.748.854.330.746.350.355.235.043.950.7237.4282.7241.6301.8166.6136.1166.9100.1195.3125.356.339.854.865.4144.5
Percentage of Assets1.00.71.21.21.21.21.21.61.41.31.01.81.61.01.91.01.41.31.82.00.81.41.61.90.81.31.81.72.12.32.21.21.11.50.91.81.00.50.81.10.91.9
Percentage of Assets lnt:Ipl1.91.32.12.22.22.22.22.82.62.41.83.33.01.93.51.92.62.43.33.71.42.73.03.51.62.53.43.24.04.44.32.32.13.01.73.42.01.01.52.21.73.5

lnt:Wpl


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value182183192170166181190184180198190180170192212185193212226190185192185173166188185767798737074898384728276807484
Percentage of AccountsReceivableNetCurrent48.356.346.642.643.245.747.540.842.947.554.338.841.255.944.055.345.449.945.938.858.649.346.640.656.052.143.591.090.192.789.290.488.190.687.890.188.589.640.440.558.169.9
Percentage of Assets1.01.01.11.01.01.11.11.11.11.31.21.21.21.31.51.31.41.61.71.51.51.51.51.41.41.61.50.70.70.90.70.60.70.80.80.80.70.90.80.80.80.9
Percentage of Assets lnt:Wpl2.62.62.82.52.52.82.92.92.83.23.13.02.93.33.73.33.54.04.33.53.53.63.53.33.23.63.61.61.62.11.51.51.61.91.72.01.72.01.92.01.92.2

Inventory Raw Materials And Supplies

us-gaap:InventoryRawMaterialsAndSupplies

us-gaap:InventoryRawMaterialsAndSupplies


Inventory
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value1191221051131071051001061051051011061091091059994888689838381838281727275726971686463616161586161646153
Percentage of InventoryRawMaterialsAndSupplies100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.70.70.60.60.60.60.60.60.70.70.70.70.70.80.70.70.70.70.60.70.70.70.70.70.70.70.60.60.70.60.60.60.60.60.60.60.60.60.60.60.70.70.70.6

us-gaap:InventoryRawMaterialsAndSupplies dei:LegalEntity

lnt:Ipl


Inventory
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value727363636060556058565559606160525148465048474546474842414340393937343333323231333433
Percentage of InventoryRawMaterialsAndSupplies60.559.860.055.856.457.654.756.455.254.154.655.555.656.157.453.154.755.053.755.957.756.456.155.757.759.057.656.757.156.356.655.755.253.352.854.253.753.253.854.355.654.4
Percentage of Assets0.40.40.40.40.30.40.30.40.40.40.40.40.40.40.40.40.40.40.30.40.40.40.40.40.40.40.30.40.40.40.40.40.30.30.30.30.30.30.30.40.40.4
Percentage of Assets lnt:Ipl0.70.80.60.60.60.60.60.60.70.70.70.70.80.80.80.70.70.70.60.70.70.70.70.70.70.70.60.70.70.70.70.70.70.60.60.60.60.60.60.70.70.7

lnt:Wpl


Inventory
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value444740484442434344454244454442433936363532343335323129293029282929292826262725262625
Percentage of InventoryRawMaterialsAndSupplies37.038.538.142.541.440.242.940.942.243.142.341.741.340.939.944.041.841.141.939.939.240.841.242.239.938.740.140.939.941.141.541.842.544.745.243.543.544.643.943.742.841.7
Percentage of Assets0.20.30.20.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.20.30.30.30.30.30.30.30.30.30.30.30.30.30.30.3
Percentage of Assets lnt:Wpl0.60.70.60.70.70.60.70.70.70.70.70.70.80.80.70.80.70.70.70.70.60.60.60.70.60.60.60.60.60.60.60.60.60.60.60.60.60.70.60.70.70.7

Other Assets Current

us-gaap:OtherAssetsCurrent

us-gaap:OtherAssetsCurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value2041171231181331371011371511538012611385871011127095989864792174352271162942892098411912515743413460153132185192111112
Percentage of OtherAssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.10.70.70.70.80.80.60.80.91.00.50.80.80.60.60.70.80.50.70.80.80.50.61.73.51.91.02.52.51.90.81.11.21.50.40.40.40.61.61.42.02.01.21.2

us-gaap:OtherAssetsCurrent dei:LegalEntity

lnt:Ipl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value535327533228302221214338292332393614273733132811530813665166168106343850542411112633212222
Percentage of OtherAssetsCurrent26.045.322.044.924.420.729.516.114.413.953.930.026.027.036.838.832.820.929.037.633.921.435.452.970.760.055.656.758.050.840.632.740.234.556.828.532.444.022.016.112.120.0
Percentage of Assets0.30.30.20.30.20.20.20.10.10.10.30.20.20.20.20.30.30.10.20.30.30.10.20.92.51.10.51.41.51.00.30.40.50.50.20.10.10.30.30.20.20.2
Percentage of Assets lnt:Ipl0.50.50.30.50.30.30.30.20.20.20.50.50.40.30.40.50.50.20.40.50.50.20.41.74.72.11.02.72.81.80.60.70.91.00.50.20.20.50.70.40.50.5

lnt:Wpl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value924712225288618610810320607157136463452053555120945183231131099217495763162025271624159.4
Percentage of OtherAssetsCurrent45.140.29.818.639.164.360.763.272.067.525.847.863.067.215.363.756.864.621.754.556.379.526.043.311.936.619.838.637.844.120.741.645.640.437.049.974.245.510.618.88.18.4
Percentage of Assets0.50.30.10.10.30.50.40.50.70.70.10.40.50.40.10.50.50.30.20.40.40.40.20.70.40.70.21.01.00.80.20.50.50.60.10.20.30.30.20.30.20.1
Percentage of Assets lnt:Wpl1.30.70.20.30.81.30.91.41.71.70.31.01.21.00.21.21.20.90.41.01.01.00.41.81.01.60.52.32.21.90.41.01.21.40.30.50.60.70.40.60.40.2

us-gaap:OtherAssetsCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-31
Value5.06.04.0
Percentage of OtherAssetsCurrent4.15.95.0
Percentage of Assets0.00.00.0
Percentage of Assets srt:ParentCompany0.10.10.1

Assets Noncurrent

us-gaap:AssetsNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:AssetsNoncurrent

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Assets
Period End2020-12-312019-12-31
Value63885964
Percentage of AssetsNoncurrent100.0100.0
Percentage of Assets36.135.7
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees0.00.0

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:PropertyPlantAndEquipmentNet


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value145401435314336141991393613685135271313112854126651246212005116951143911234109311060810448102799920984696269519936691739050893887638566842683268141802779137838738472487081703769376866682367306192
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets81.181.680.981.080.781.181.079.479.780.680.878.680.080.379.277.477.277.676.976.177.676.876.274.674.574.974.075.675.275.874.974.173.773.772.772.073.073.572.673.273.872.672.568.5

us-gaap:PropertyPlantAndEquipmentNet dei:LegalEntity

lnt:Ipl


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value790778727889781876667589748072837080694767816432619360885926576455865503543552205127499349254804468746314554443342794194413640213962390338583799374236923676363236153703
Percentage of PropertyPlantAndEquipmentNet54.454.855.055.155.055.555.355.555.154.954.453.653.053.252.852.752.752.752.952.652.151.951.751.351.151.251.050.650.049.849.749.449.449.349.251.551.652.152.252.452.755.0
Percentage of Assets44.144.744.544.644.445.044.844.143.944.244.042.142.442.841.840.840.640.940.640.140.439.839.438.338.138.337.738.237.637.737.236.636.436.435.837.137.738.337.938.338.939.9
Percentage of Assets lnt:Ipl80.580.980.179.379.280.780.678.380.280.480.676.878.979.877.975.074.475.274.472.975.474.473.470.971.272.270.571.671.371.971.370.670.670.670.770.471.972.972.273.274.075.0

lnt:Wpl


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value620360536022597758675691563854495377532252875183511849624917478246354523442642894227414141034094402839663938390138663818378137363684363336013147309130493021298429442846
Percentage of PropertyPlantAndEquipmentNet42.742.242.042.142.141.641.741.541.842.042.443.243.843.443.843.843.743.343.143.242.943.043.143.743.943.844.144.545.145.345.445.945.945.945.942.642.643.142.943.042.942.3
Percentage of Assets34.634.434.034.134.033.733.833.033.433.934.333.935.034.834.733.933.733.633.132.933.333.032.832.632.732.832.633.634.034.334.034.033.833.933.430.731.131.731.231.531.730.7
Percentage of Assets lnt:Wpl87.287.687.188.688.286.986.786.384.286.385.985.886.686.285.485.585.084.883.779.379.178.177.977.877.476.876.879.579.279.378.777.677.077.075.673.974.475.174.775.876.073.2

Long Term Investments

us-gaap:LongTermInvestments

us-gaap:LongTermInvestments


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value506494485478473469467453443433431424420414396458354346337329324323346353349343344343338332329324321321319314308303300299296292289281
Percentage of LongTermInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.82.82.72.72.72.82.82.72.72.82.82.82.92.92.83.22.62.62.52.52.62.62.82.82.82.82.93.03.03.03.03.03.03.03.03.13.13.23.13.23.23.13.13.1

us-gaap:LongTermInvestments us-gaap:ConsolidatedEntities

srt:ParentCompany


Long
Period End2020-12-312019-12-312018-12-31
Value666660185519
Percentage of LongTermInvestments1374.41286.41279.6
Percentage of Assets37.636.035.8
Percentage of Assets srt:ParentCompany98.298.098.1

Operating Lease Right Of Use Asset

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:OperatingLeaseRightOfUseAsset


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value1516171718
Percentage of OperatingLeaseRightOfUseAsset100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.10.1

us-gaap:OperatingLeaseRightOfUseAsset dei:LegalEntity

lnt:Ipl


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value9.010.010.010.010.0
Percentage of OperatingLeaseRightOfUseAsset60.062.558.858.855.6
Percentage of Assets0.10.10.10.10.1
Percentage of Assets lnt:Ipl0.10.10.10.10.1

lnt:Wpl


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value6.06.07.07.07.0
Percentage of OperatingLeaseRightOfUseAsset40.037.541.241.238.9
Percentage of Assets0.00.00.00.00.0
Percentage of Assets lnt:Wpl0.10.10.10.10.1

Other Assets Noncurrent

us-gaap:OtherAssetsNoncurrent

us-gaap:OtherAssetsNoncurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value1994199220021830181518127272687289103867269211814229.41010143538414355676885991111081059876829293121130137172
Percentage of OtherAssetsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets11.111.311.310.410.510.70.40.40.40.50.60.70.60.50.50.20.10.10.20.10.10.10.10.30.30.30.40.50.60.60.80.91.01.01.01.00.80.91.01.01.31.41.51.9

us-gaap:OtherAssetsNoncurrent dei:LegalEntity

lnt:Ipl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1463146114641402138813793128191918201616148.58.66.64.73.84.44.45.016151212182629292121201919171919214949
Percentage of OtherAssetsNoncurrent73.473.373.176.676.576.143.938.728.526.820.419.519.222.420.239.746.244.320.840.440.441.134.247.139.331.328.933.238.742.334.622.118.819.118.319.723.023.220.823.140.735.7
Percentage of Assets8.28.38.38.08.08.20.20.20.10.10.10.10.10.10.10.10.10.00.00.00.00.00.00.10.10.10.10.20.20.30.30.20.20.20.20.20.20.20.20.20.50.5
Percentage of Assets lnt:Ipl14.915.014.914.214.314.70.30.30.20.20.20.20.20.20.20.10.10.10.10.10.10.10.10.20.20.20.20.30.40.50.50.40.40.40.40.40.30.40.40.41.01.0

lnt:Wpl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value531527528429424425231921246257432927252320176.98.56.79.120232729384238545163585753343644474957
Percentage of OtherAssetsNoncurrent26.626.526.423.423.423.531.926.931.733.070.155.350.340.639.2120.1126.3139.676.173.478.062.662.356.962.367.767.769.762.756.163.351.856.353.954.754.644.544.548.550.540.741.9
Percentage of Assets3.03.03.02.42.52.50.10.10.10.20.40.40.30.20.20.20.20.20.10.10.10.10.10.20.20.20.20.30.40.30.50.50.60.50.50.50.30.40.50.50.50.6
Percentage of Assets lnt:Wpl7.57.67.66.46.46.50.40.30.30.41.00.90.70.50.50.50.40.40.30.10.20.10.20.40.50.50.60.80.90.81.11.11.31.21.21.30.80.91.11.21.31.5

us-gaap:OtherAssetsNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-31
Value888981
Percentage of OtherAssetsNoncurrent4.4123.690.3
Percentage of Assets0.50.50.5
Percentage of Assets srt:ParentCompany1.31.41.4

Accounts Payable Current

us-gaap:AccountsPayableCurrent

us-gaap:AccountsPayableCurrent


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value392307377417429375422497422387543498431363477478381369445365353323402438374356427471475388365368391368339418337263308314305300336331
Percentage of AccountsPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.21.72.12.42.52.22.53.02.62.53.53.32.92.53.43.42.82.73.32.82.82.63.23.53.03.03.54.14.23.53.33.43.63.43.14.13.42.73.23.33.33.23.63.7

us-gaap:AccountsPayableCurrent dei:LegalEntity

lnt:Ipl


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value126119162231207184207290216227304279203183220224163149186172160153197251222199259286262214187195213204163231171136118116119146
Percentage of AccountsPayableCurrent32.138.843.055.448.249.149.058.351.358.656.156.047.250.546.247.043.040.441.847.345.447.449.057.359.255.960.760.755.355.351.352.954.655.448.155.450.951.838.437.039.243.4
Percentage of Assets0.70.70.91.31.21.11.21.81.31.42.01.81.41.31.61.61.21.11.41.31.31.21.62.01.81.72.12.52.31.91.71.82.01.91.52.31.71.41.21.21.31.6
Percentage of Assets lnt:Ipl1.31.21.62.32.12.02.23.12.52.63.63.32.62.42.92.92.22.02.62.42.42.32.93.73.43.14.04.64.43.73.23.43.83.73.04.33.32.72.32.32.53.0

lnt:Wpl


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value20312515412618313615915115010418016217313420119715015719212213011113612298107112118152114120117124115126133106859893100118
Percentage of AccountsPayableCurrent51.840.740.830.242.636.337.930.435.527.033.332.640.337.142.341.239.542.543.333.537.034.333.827.926.130.226.425.132.029.432.932.031.731.437.331.931.532.232.029.832.735.2
Percentage of Assets1.10.70.90.71.10.81.00.90.90.71.21.11.20.91.41.41.11.21.40.91.00.91.11.00.80.90.91.01.31.01.11.11.11.11.21.31.10.91.01.01.11.3
Percentage of Assets lnt:Wpl2.91.82.21.92.82.12.52.42.31.72.92.72.92.33.53.52.82.93.62.32.42.12.62.31.92.12.22.43.12.42.52.42.62.52.73.12.62.12.42.42.63.0

Liabilities Current

us-gaap:LiabilitiesCurrent

us-gaap:LiabilitiesCurrent


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value1639140812971295122016502054208219491587164415481257207321491470120811651162136913731348135999099110231214174117331384143310521072103810209459577738557747607788661076
Percentage of LiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets9.18.07.37.47.19.812.312.612.110.110.710.18.614.615.110.48.88.78.710.510.810.810.97.98.18.510.115.015.212.512.99.69.99.79.59.29.68.08.88.28.28.39.311.9

us-gaap:LiabilitiesCurrent dei:LegalEntity

lnt:Ipl


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value370337447546632835830882494484607798815798827603490493521487488484531551543644705771771507524517527520468490466414422389435482
Percentage of LiabilitiesCurrent22.623.934.542.251.850.640.442.425.430.536.951.664.938.538.541.040.642.444.935.635.636.039.155.754.863.058.144.344.536.736.649.149.250.246.051.948.853.649.450.257.355.7
Percentage of Assets2.11.92.53.13.74.95.05.33.13.13.95.25.65.65.84.33.63.73.93.73.83.94.34.44.45.35.86.66.84.64.74.74.84.94.34.84.74.34.44.14.75.2
Percentage of Assets lnt:Ipl3.83.54.55.56.58.99.09.55.65.67.29.510.410.510.97.86.56.77.16.87.27.27.98.18.210.010.912.412.98.79.09.19.49.48.69.19.08.28.37.88.99.8

lnt:Wpl


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value599505674428409700690508743677694601343352396589531420394303353343336295297314310459472431451419435422385287286250257216217292
Percentage of LiabilitiesCurrent36.535.952.033.133.542.433.624.438.242.742.238.927.317.018.440.143.936.134.022.225.725.524.829.830.030.725.526.427.331.231.539.840.640.737.830.429.932.330.127.928.633.8
Percentage of Assets3.32.93.82.42.44.14.13.14.64.34.53.92.32.52.84.23.93.13.02.32.82.72.72.42.42.62.64.04.13.94.13.84.03.93.62.82.92.62.72.32.33.2
Percentage of Assets lnt:Wpl8.47.39.86.36.210.710.68.011.611.011.310.05.86.16.910.59.77.97.55.66.66.56.45.65.76.16.19.49.79.09.48.79.19.08.16.86.96.26.45.55.67.5

us-gaap:LiabilitiesCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilities
Period End2020-12-312019-12-312018-12-31
Value10989191025
Percentage of LiabilitiesCurrent84.744.762.3
Percentage of Assets6.25.56.6
Percentage of Assets srt:ParentCompany16.215.018.2

us-gaap:LiabilitiesCurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value317507
Percentage of LiabilitiesCurrent24.424.7
Percentage of Assets1.83.0
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees0.00.0

Long Term Debt Current

us-gaap:LongTermDebtCurrent

us-gaap:LongTermDebtCurrent


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value3083088.07.07.43576576567062562565063568558551055.24.64.63143143133133.033183183492509358358481.51.51.51.41.41.41.41.41.41.31.3101
Percentage of LongTermDebtCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.71.80.00.00.02.13.94.04.41.61.73.32.46.06.00.70.00.00.02.42.52.52.50.00.31.51.54.34.53.23.20.40.00.00.00.00.00.00.00.00.00.00.01.1

Operating Lease Liability Current

us-gaap:OperatingLeaseLiabilityCurrent

us-gaap:OperatingLeaseLiabilityCurrent


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value2000000.02000000.02000000.02000000.03000000.0
Percentage of OperatingLeaseLiabilityCurrent100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.0

Other Liabilities Current

us-gaap:OtherLiabilitiesCurrent

us-gaap:OtherLiabilitiesCurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value230249207286386407425389262249260255247251260217265272222273284304296250264232262204215191133223244196113999387127152161163160117
Percentage of OtherLiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.31.41.21.62.22.42.52.41.61.61.71.71.71.81.81.51.92.01.72.12.22.42.42.02.11.92.21.81.91.71.22.02.21.81.11.00.90.91.31.61.71.71.71.3

us-gaap:OtherLiabilitiesCurrent dei:LegalEntity

lnt:Ipl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1801314919829326520719787150561731701279092194131578518219869125148122906811961741131371143634313132262835
Percentage of OtherLiabilitiesCurrent78.352.623.769.276.065.148.850.833.560.421.568.068.750.734.742.873.348.225.731.464.365.123.449.956.052.834.333.555.532.356.251.056.458.231.934.434.035.525.317.417.422.1
Percentage of Assets1.00.70.31.11.71.61.21.20.51.00.41.11.20.90.60.71.41.00.40.71.41.60.61.01.21.00.70.61.10.60.71.01.31.10.30.30.30.30.30.30.30.4
Percentage of Assets lnt:Ipl1.81.30.52.03.02.82.22.11.01.70.72.12.21.71.21.22.61.80.81.22.73.01.01.82.21.91.41.12.01.11.32.02.52.10.70.60.60.60.60.50.60.7

lnt:Wpl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value94948211779128741131091124895958951108112123549112014679868282465460643659721263238333432293338
Percentage of OtherLiabilitiesCurrent40.937.839.640.920.631.517.529.241.645.218.537.238.535.819.750.142.445.124.633.242.548.126.834.531.235.617.826.927.833.427.726.529.664.628.438.635.939.225.319.220.624.3
Percentage of Assets0.50.50.50.70.50.80.40.70.70.70.30.60.70.60.40.80.80.90.40.71.01.20.60.70.70.70.40.50.50.60.30.50.71.20.30.40.30.40.30.30.40.4
Percentage of Assets lnt:Wpl1.31.41.21.71.22.01.11.81.71.80.81.61.61.60.91.92.12.31.01.72.32.81.51.61.61.60.91.11.21.30.81.21.52.70.70.90.80.80.80.70.91.0

us-gaap:OtherLiabilitiesCurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-31
Value291921
Percentage of OtherLiabilitiesCurrent14.04.58.1
Percentage of Assets0.20.10.1
Percentage of Assets srt:ParentCompany0.40.30.4

Taxes Payable Current

us-gaap:TaxesPayableCurrent

us-gaap:TaxesPayableCurrent


Taxes
Period End2020-12-312019-12-312017-09-302016-12-312015-12-312013-12-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value67703959535048374639473745374577
Percentage of TaxesPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.30.40.40.40.40.40.50.40.50.40.50.40.50.9

us-gaap:TaxesPayableCurrent dei:LegalEntity

lnt:Ipl


Taxes
Period End2020-12-312019-12-312019-09-302019-06-302018-12-312017-12-312017-09-302017-03-312016-12-312016-09-302015-12-312014-12-312014-09-302014-03-312013-12-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value5463586445473937534167453437514638674843345762
Percentage of TaxesPayableCurrent80.690.40.00.00.00.099.70.090.40.0127.10.00.00.0102.297.5101.6145.1121.791.490.5125.3137.7
Percentage of Assets0.30.40.40.40.30.30.30.30.40.30.50.40.30.30.50.40.40.70.50.50.40.60.7
Percentage of Assets lnt:Ipl0.50.70.60.70.50.60.50.50.70.61.00.70.60.60.90.90.71.31.00.90.71.21.3

Liabilities Noncurrent

us-gaap:LiabilitiesNoncurrent us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:LiabilitiesNoncurrent

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Liabilities
Period End2020-12-312019-12-31
Value29972659
Percentage of LiabilitiesNoncurrent100.0100.0
Percentage of Assets16.915.9
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees0.00.0

Long Term Debt

us-gaap:LongTermDebt dei:LegalEntity, us-gaap:FairValueByMeasurementBasis

us-gaap:LongTermDebt

lnt:Ipl, us-gaap:CarryingReportedAmountFairValueDisclosure


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302015-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-31
Value33463346334533443343314731473146285026672552280125312452240621952194215421532153185615201558155815581374136413441359
Percentage of LongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets18.719.018.919.119.418.618.819.017.717.016.518.317.317.217.015.616.016.016.116.514.913.113.714.014.012.512.512.512.6
Percentage of Assets lnt:Ipl us-gaap:CarryingReportedAmountFairValueDisclosure0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:CarryingReportedAmountFairValueDisclosure


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302015-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-31
Value21312131213021302129193319321932218118351834183418341833183315361535153515351534153313241332133213321332133113311331
Percentage of LongTermDebt63.763.763.763.763.761.461.461.476.568.871.965.572.474.876.270.070.071.371.371.382.687.185.585.585.596.997.699.097.9
Percentage of Assets11.912.112.012.112.311.511.611.713.511.711.912.012.512.912.910.911.211.411.511.812.311.411.712.012.012.112.212.412.3
Percentage of Assets lnt:Wpl us-gaap:CarryingReportedAmountFairValueDisclosure0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:LongTermDebt us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302015-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-31
Value67766779677765816579619161906191614456185502575454834912486643604359432043204130383532923338333933363153314231233138
Percentage of LongTermDebt202.5202.6202.6196.8196.8196.7196.7196.8215.6210.6215.6205.4216.6200.3202.3198.6198.7200.6200.6191.9206.6216.6214.2214.3214.1229.4230.3232.3230.8
Percentage of Assets37.838.538.337.538.136.737.137.538.135.835.737.737.534.534.330.931.732.132.331.730.728.429.330.030.028.728.929.129.1
Percentage of Assets us-gaap:CarryingReportedAmountFairValueDisclosure0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Long Term Debt Noncurrent

us-gaap:LongTermDebtNoncurrent

us-gaap:LongTermDebtNoncurrent


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value64686471676965746572583355335535543853625246524851274056401042554354431643153816358835223522385537173606360627992829298029773104314131213136282827522728270327032703270327032404
Percentage of LongTermDebtNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets36.136.838.237.538.134.633.133.533.734.134.034.435.128.528.330.131.732.132.329.328.328.128.230.730.229.929.824.124.926.826.828.328.929.129.127.627.728.327.928.529.128.829.126.6

us-gaap:LongTermDebtNoncurrent dei:LegalEntity

lnt:Ipl


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value334633463345334433432947294729462850266725522551218121022056209521942154215321531924185718561868173016181618137013701520152013361364134413591359135913341309130813081308
Percentage of LongTermDebtNoncurrent51.751.749.450.950.950.553.353.252.449.848.648.642.651.851.349.250.449.949.956.453.652.752.748.546.544.944.948.948.451.051.043.043.443.143.348.149.448.948.448.448.448.4
Percentage of Assets18.719.018.919.119.417.517.617.817.717.016.516.714.914.814.514.816.016.016.116.515.214.814.914.914.113.413.411.812.013.713.712.212.512.512.613.313.713.913.513.814.114.1
Percentage of Assets lnt:Ipl34.134.434.033.934.531.331.831.732.330.930.330.527.827.627.027.329.229.429.530.128.327.727.727.626.325.225.122.122.826.126.223.524.324.324.925.226.126.325.726.426.826.5

lnt:Wpl


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value213121312130213021291783178217821781158515841584183418331833153615351535153515341534153415331543154315431543129313231323132313231331133113311082108210821082108210821081
Percentage of LongTermDebtNoncurrent32.932.931.532.432.430.632.232.232.829.630.230.235.845.245.736.135.335.635.640.242.843.643.540.041.542.842.846.246.844.444.442.642.442.742.538.339.339.740.040.040.040.0
Percentage of Assets11.912.112.012.112.310.610.710.811.110.110.310.412.512.912.910.911.211.411.511.812.112.212.312.312.512.812.811.211.611.911.912.112.212.412.310.610.911.211.211.411.611.7
Percentage of Assets lnt:Wpl29.930.830.831.632.027.227.428.227.925.725.826.231.031.831.827.528.228.829.028.428.728.929.129.329.729.930.126.427.127.527.527.527.928.228.025.426.026.726.827.527.927.8

Deferred Income Tax Liabilities Net

us-gaap:DeferredIncomeTaxLiabilitiesNet

us-gaap:DeferredIncomeTaxLiabilitiesNet


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1865184318141803176117361714
Percentage of DeferredIncomeTaxLiabilitiesNet100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets10.410.510.210.310.210.310.3

us-gaap:DeferredIncomeTaxLiabilitiesNet dei:LegalEntity

lnt:Ipl


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1054104710351028101210101008
Percentage of DeferredIncomeTaxLiabilitiesNet56.556.857.157.057.558.258.8
Percentage of Assets5.96.05.85.95.96.06.0
Percentage of Assets lnt:Ipl10.710.810.510.410.510.710.9

lnt:Wpl


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value730719702696667647626
Percentage of DeferredIncomeTaxLiabilitiesNet39.139.038.738.637.937.336.5
Percentage of Assets4.14.14.04.03.93.83.7
Percentage of Assets lnt:Wpl10.310.410.210.310.09.99.6

Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent


Pension
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value477495511423450452484476487493509487488488504481482481489455452446451416417417421201202203206356359360364310309309312235241299303323
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.72.82.92.42.62.72.92.93.03.13.33.23.33.43.63.43.53.63.73.53.63.63.63.33.43.53.51.71.81.81.93.23.33.43.43.03.13.23.22.52.63.23.33.6

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent dei:LegalEntity

lnt:Ipl


Pension
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value17118018614916016116716517117417816817017117317117117217316116016016014114114214246474748120121122122991001001017274110
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent35.836.436.435.235.635.734.634.735.135.435.034.634.835.134.535.635.635.735.435.435.635.935.533.933.934.033.823.023.323.623.533.733.733.933.832.132.432.632.630.831.036.3
Percentage of Assets1.01.01.10.80.91.01.01.01.11.11.21.11.21.21.21.21.31.31.31.21.31.31.31.11.11.21.20.40.40.40.41.11.11.11.11.01.01.01.10.80.81.2
Percentage of Assets lnt:Ipl1.71.91.91.51.71.71.81.81.92.02.12.02.22.22.32.22.32.42.42.32.42.42.42.12.12.22.20.70.80.80.82.12.22.22.31.81.92.02.01.51.52.2

lnt:Wpl


Pension
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value20521522218920120321020321021421720720921021320420520520718618618618817817917918084858788156158159159127127127128103103119
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent43.043.443.444.744.845.043.642.743.243.442.842.542.843.142.442.442.542.742.440.941.241.741.842.842.943.042.841.942.243.142.844.044.044.343.941.141.041.240.944.042.939.2
Percentage of Assets1.11.21.31.11.21.21.31.21.31.41.41.41.41.51.51.41.51.51.61.41.51.51.51.41.51.51.50.70.70.80.81.41.51.51.51.21.31.31.31.11.11.3
Percentage of Assets lnt:Wpl2.93.13.22.83.03.13.23.23.33.53.53.43.53.73.73.73.83.93.93.43.53.53.63.43.43.53.51.71.71.81.83.33.33.43.43.03.13.13.22.62.73.1

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent dei:LegalEntity, us-gaap:RetirementPlanType

lnt:Ipl, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-31
Value19181820
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent3.73.83.74.0
Percentage of Assets0.10.10.10.1
Percentage of Assets lnt:Ipl us-gaap:OtherPostretirementBenefitPlansDefinedBenefit0.00.00.00.0

lnt:Ipl, us-gaap:PensionPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-31
Value161144155148
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent31.529.930.529.5
Percentage of Assets0.90.91.01.0
Percentage of Assets lnt:Ipl us-gaap:PensionPlansDefinedBenefit0.00.00.00.0

lnt:Wpl, us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-31
Value68656167
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent13.313.512.213.5
Percentage of Assets0.40.40.40.5
Percentage of Assets lnt:Wpl us-gaap:OtherPostretirementBenefitPlansDefinedBenefit0.00.00.00.0

lnt:Wpl, us-gaap:PensionPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-31
Value152144154144
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent29.729.830.328.7
Percentage of Assets0.90.91.01.0
Percentage of Assets lnt:Wpl us-gaap:PensionPlansDefinedBenefit0.00.00.00.0

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent us-gaap:RetirementPlanType

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-31
Value119110104110
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent23.322.820.622.0
Percentage of Assets0.70.70.70.8
Percentage of Assets us-gaap:OtherPostretirementBenefitPlansDefinedBenefit0.00.00.00.0

us-gaap:PensionPlansDefinedBenefit


Pension
Period End2020-12-312019-12-312018-12-312017-12-31
Value365335364350
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent71.469.271.569.5
Percentage of Assets2.12.02.42.5
Percentage of Assets us-gaap:PensionPlansDefinedBenefit0.00.00.00.0

Minority Interest

us-gaap:MinorityInterest us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:MinorityInterest

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Minority
Period End2020-12-312019-12-31
Value192208
Percentage of MinorityInterest100.0100.0
Percentage of Assets1.11.2
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees0.00.0

Other Liabilities Noncurrent

us-gaap:OtherLiabilitiesNoncurrent

us-gaap:OtherLiabilitiesNoncurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value391364374348357349298305413442287286310313306296288297279300297310306333342259260267253262273271275257262269245248259251212208208294
Percentage of OtherLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.22.12.12.02.12.11.81.82.62.81.91.92.12.22.22.12.12.22.12.32.32.52.42.72.82.12.22.32.22.42.52.52.52.42.42.62.52.62.72.72.32.22.33.3

us-gaap:OtherLiabilitiesNoncurrent dei:LegalEntity

lnt:Ipl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value322300299287273269253251360365220221242239242238228221214229227223229231243177185182174171169181183178182189186188199187143141
Percentage of OtherLiabilitiesNoncurrent82.482.479.982.576.577.084.882.187.282.576.877.178.076.279.180.579.374.276.776.376.772.174.969.470.968.371.368.168.765.561.866.766.769.369.770.676.275.776.874.467.667.8
Percentage of Assets1.81.71.71.61.61.61.51.52.22.31.41.41.71.71.71.71.71.61.61.81.81.81.81.82.01.51.51.61.51.51.51.71.71.71.71.91.92.02.12.01.51.5
Percentage of Assets lnt:Ipl3.33.13.02.92.82.92.72.74.14.22.62.63.13.13.23.13.03.02.93.23.43.33.43.43.72.82.92.92.92.92.93.23.33.23.43.53.63.73.93.82.92.9

lnt:Wpl


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value193183180161168162168164159188178175174172167162163168159162157169162181177159155138133142153153155141144148135135136124132135
Percentage of OtherLiabilitiesNoncurrent49.450.348.146.347.346.556.453.938.642.562.061.256.355.054.754.956.856.757.154.152.954.552.954.551.961.459.752.052.554.355.956.556.455.055.155.355.154.652.749.562.464.7
Percentage of Assets1.11.01.00.91.01.01.01.01.01.21.21.11.21.21.21.21.21.31.21.21.21.31.31.41.41.31.31.21.21.31.41.41.41.31.31.51.41.41.41.31.41.5
Percentage of Assets lnt:Wpl2.72.62.62.42.52.52.62.62.53.12.92.93.03.02.92.93.03.23.03.02.93.23.13.53.43.13.02.82.73.03.23.23.33.03.03.53.23.33.43.23.43.5

us-gaap:OtherLiabilitiesNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-31
Value2.01517
Percentage of OtherLiabilitiesNoncurrent0.55.05.9
Percentage of Assets0.00.10.1
Percentage of Assets srt:ParentCompany0.00.20.3

Operating Lease Liability Noncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value1314151515
Percentage of OperatingLeaseLiabilityNoncurrent100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.10.1

us-gaap:OperatingLeaseLiabilityNoncurrent dei:LegalEntity

lnt:Ipl


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value8.09.09.09.09.0
Percentage of OperatingLeaseLiabilityNoncurrent61.564.360.060.060.0
Percentage of Assets0.00.10.10.10.1
Percentage of Assets lnt:Ipl0.10.10.10.10.1

lnt:Wpl


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value5.05.06.06.06.0
Percentage of OperatingLeaseLiabilityNoncurrent38.535.740.040.040.0
Percentage of Assets0.00.00.00.00.0
Percentage of Assets lnt:Wpl0.10.10.10.10.1

Lessee Operating Lease Liability Payments Due After Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value8.010.0131313
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive100.0100.0100.0100.0100.0
Percentage of Assets0.00.10.10.10.1

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive dei:LegalEntity

lnt:Ipl


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value6.07.09.09.09.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive75.070.069.269.269.2
Percentage of Assets0.00.00.10.10.1
Percentage of Assets lnt:Ipl0.10.10.10.10.1

lnt:Wpl


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value2.03.04.04.03.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive25.030.030.830.823.1
Percentage of Assets0.00.00.00.00.0
Percentage of Assets lnt:Wpl0.00.00.10.10.0

Operating Lease Liability

us-gaap:OperatingLeaseLiability

us-gaap:OperatingLeaseLiability


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value1516171718
Percentage of OperatingLeaseLiability100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.10.1

us-gaap:OperatingLeaseLiability dei:LegalEntity

lnt:Ipl


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value9.010.010.010.010.0
Percentage of OperatingLeaseLiability60.062.558.858.855.6
Percentage of Assets0.10.10.10.10.1
Percentage of Assets lnt:Ipl0.10.10.10.10.1

lnt:Wpl


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value6.06.07.07.07.0
Percentage of OperatingLeaseLiability40.037.541.241.238.9
Percentage of Assets0.00.00.00.00.0
Percentage of Assets lnt:Wpl0.10.10.10.10.1

Lessee Operating Lease Liability Payments Due

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value1820212323
Percentage of LesseeOperatingLeaseLiabilityPaymentsDue100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.10.1

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue dei:LegalEntity

lnt:Ipl


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value1112131414
Percentage of LesseeOperatingLeaseLiabilityPaymentsDue61.160.061.960.960.9
Percentage of Assets0.10.10.10.10.1
Percentage of Assets lnt:Ipl0.10.10.10.20.2

lnt:Wpl


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value7.08.08.09.08.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDue38.940.038.139.134.8
Percentage of Assets0.00.00.00.10.1
Percentage of Assets lnt:Wpl0.10.10.10.10.1

Lessee Operating Lease Liability Undiscounted Excess Amount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value3000000.04000000.04000000.06000000.05000000.0
Percentage of LesseeOperatingLeaseLiabilityUndiscountedExcessAmount100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.0

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount dei:LegalEntity

lnt:Ipl


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value2000000.02000000.03000000.04000000.04000000.0
Percentage of LesseeOperatingLeaseLiabilityUndiscountedExcessAmount66.750.075.066.780.0
Percentage of Assets0.00.00.00.00.0
Percentage of Assets lnt:Ipl0.00.00.00.00.0

lnt:Wpl


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value1000000.02000000.01000000.02000000.01000000.0
Percentage of LesseeOperatingLeaseLiabilityUndiscountedExcessAmount33.350.025.033.320.0
Percentage of Assets0.00.00.00.00.0
Percentage of Assets lnt:Wpl0.00.00.00.00.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-312007-12-31
Value5819576656885709554855025205496946994682458545704350423141824154405038963862385937903764372437453620359734383435333733313281326631603145313431163014299730133001292729202893277228232681
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets32.432.832.132.532.132.631.230.129.229.829.729.929.829.729.529.429.528.928.929.629.930.029.829.829.429.828.529.629.330.029.529.729.029.329.130.430.331.131.131.731.531.131.230.70.00.0

us-gaap:StockholdersEquity dei:LegalEntity

lnt:Ipl


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-312008-12-31
Value37793742376437303471339532713244314531423030283826542514250924322351224722492137203620421995199119081826181418291731171816791663155515351519149813951360139413631294138913301148
Percentage of StockholdersEquity64.964.966.265.362.661.762.965.366.967.166.162.161.059.460.058.658.057.758.255.453.754.353.653.252.750.852.853.251.951.651.250.949.248.848.548.146.345.446.345.444.248.048.040.7
Percentage of Assets21.121.321.321.320.120.119.619.619.520.019.618.618.217.717.717.217.116.716.816.416.116.316.015.915.515.115.015.815.215.515.115.214.314.314.114.614.014.114.414.413.915.014.70.0
Percentage of Assets lnt:Ipl38.538.538.237.835.936.135.334.935.636.336.033.933.833.033.031.731.330.730.829.930.030.429.729.429.028.528.129.528.929.528.929.227.727.827.827.726.826.827.427.526.528.127.20.0

lnt:Wpl


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-312008-12-31
Value27252645247824822451243623632324218521792149214620551900188118091751174417301813177817691756175917231716170317041672166716421633160115951583148014521445144214291406136912541159
Percentage of StockholdersEquity46.845.943.643.544.244.345.446.846.546.546.947.047.244.945.043.643.244.844.847.046.947.047.247.047.647.749.549.650.150.150.150.050.750.750.547.548.248.247.947.648.047.345.341.1
Percentage of Assets15.215.014.014.214.214.414.214.113.613.913.914.114.113.313.312.812.713.012.913.914.014.114.114.014.014.214.114.714.715.014.814.914.714.914.714.414.615.014.915.115.114.813.90.0
Percentage of Assets lnt:Wpl38.338.335.936.836.937.236.336.834.235.334.935.534.833.032.732.432.132.732.733.633.333.333.333.433.133.233.234.734.234.634.233.933.533.833.234.835.035.635.736.336.335.234.10.0

us-gaap:StockholdersEquity dei:LegalEntity, us-gaap:StatementEquityComponents

lnt:Ipl, us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value280227522752269325222447234723222322232222222027192717971797159714071242115210379279741042998
Percentage of StockholdersEquity48.247.748.447.245.544.545.146.749.449.648.544.444.342.543.041.437.836.135.133.130.833.737.635.3
Percentage of Assets15.615.615.515.414.614.514.114.014.414.814.413.313.212.612.711.911.310.310.49.69.610.511.50.0
Percentage of Assets lnt:Ipl us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value333333333333333333333333333333333333333333333333
Percentage of StockholdersEquity0.60.60.60.60.60.60.60.70.70.70.70.70.80.80.80.90.91.01.01.11.11.21.21.2
Percentage of Assets0.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.30.30.30.30.30.40.40.0
Percentage of Assets lnt:Ipl us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Ipl, us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value9449579791004914914890887788785774777692683678617554537493448433382254116
Percentage of StockholdersEquity16.216.617.217.616.516.617.117.916.816.816.917.015.916.116.216.014.915.615.014.314.413.29.24.1
Percentage of Assets5.35.45.55.75.35.45.35.44.95.05.05.14.74.84.84.64.44.54.44.24.54.12.80.0
Percentage of Assets lnt:Ipl us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value1669158414591459145914591434140913091309130913091259110911091019959959959959869844768668
Percentage of StockholdersEquity28.727.525.725.626.326.527.528.427.928.028.528.628.926.226.526.425.827.929.230.628.829.227.723.7
Percentage of Assets9.39.08.28.38.48.68.68.58.18.38.58.68.67.87.87.67.77.98.68.99.09.18.50.0
Percentage of Assets lnt:Wpl us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value666666666666666666666666666666666666666666666666
Percentage of StockholdersEquity1.11.11.21.21.21.21.31.31.41.41.41.41.51.61.61.71.81.92.02.12.22.32.42.3
Percentage of Assets0.40.40.40.40.40.40.40.40.40.40.40.40.50.50.50.50.50.50.60.60.70.70.70.0
Percentage of Assets lnt:Wpl us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

lnt:Wpl, us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value990995953957926910863849810804774771730725706645731678617557507459419424
Percentage of StockholdersEquity17.017.316.816.816.716.616.617.117.217.216.916.916.817.116.916.719.619.718.817.816.815.915.115.0
Percentage of Assets5.55.75.45.55.45.45.25.15.05.15.05.15.05.15.04.85.95.65.65.25.24.94.60.0
Percentage of Assets lnt:Wpl us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-31
Value569152064585
Percentage of StockholdersEquity100.1100.0100.0
Percentage of Assets32.131.229.7
Percentage of Assets srt:ParentCompany83.884.881.5

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-1.0-1.0-1.0-1.0-0.62.01.31.01.02.41.7-0.20.1-0.5-0.5-0.4-0.4-0.6-0.2-0.8-0.8-1.4-1.4-1.40.2
Percentage of StockholdersEquity-0.0-0.0-0.0-0.0-0.00.00.00.00.00.10.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.1-0.00.0
Percentage of Assets-0.0-0.0-0.0-0.0-0.00.00.00.00.00.00.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.00.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value2722271227042693268326742445223621082100204520381947185118451693166315091507151115101506149914941483
Percentage of StockholdersEquity46.847.047.547.248.448.647.045.044.944.844.644.644.843.844.143.844.743.945.948.250.152.154.152.955.3
Percentage of Assets15.215.415.315.415.515.814.613.513.113.413.313.313.313.013.012.713.312.513.614.015.616.216.60.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value3.03.02.02.02.52.52.52.42.42.42.42.42.32.32.32.31.11.11.11.11.11.11.11.11.1
Percentage of StockholdersEquity0.10.10.00.00.00.00.00.00.10.10.10.10.10.10.10.10.00.00.00.00.00.00.00.00.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:DeferredCompensationShareBasedPayments


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-11.0-11.0-11.0-11.0-10.2-9.9-10.0-10.2-10.0-9.7-9.8-9.5-11.4-11.1-11.1-10.0-8.5-8.9-8.0-7.3-8.3-7.6-7.9-7.3-8.7
Percentage of StockholdersEquity-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.3-0.3-0.3-0.3-0.2-0.3-0.2-0.2-0.3-0.3-0.3-0.3-0.3
Percentage of Assets-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.10.00.0
Percentage of Assets us-gaap:DeferredCompensationShareBasedPayments0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value3106306329943026287328332765273925972587254525392412238923462177206819381780163015101394128113361205
Percentage of StockholdersEquity53.453.152.653.051.851.553.155.155.355.355.555.655.556.556.156.455.656.454.352.050.148.246.247.345.0
Percentage of Assets17.317.416.917.316.616.816.616.616.116.516.516.616.516.816.516.316.616.016.015.115.615.014.20.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Stockholders Equity Including Portion Attributable To Noncontrolling Interest

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value60195966588859095748570254055169489948824785477045504431438243544250409640624059399039643924394638213798364036373539353334833468336233473281326231613144315931483074310730792958
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets33.633.933.233.733.333.832.431.330.431.131.031.231.131.130.930.830.930.430.431.231.531.631.431.431.031.430.131.431.131.831.331.630.931.230.431.831.832.732.633.233.133.133.232.7

us-gaap:StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest dei:LegalEntity

lnt:Ipl


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value397939423964393036713595347134443345334232303038285427142709263225512447244923372236224221952191210820262014202919311918187918631755173516641643154015051539150814401573
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest66.166.167.366.563.963.164.266.668.368.467.563.762.761.361.860.560.059.760.357.656.156.655.955.555.253.455.355.854.654.354.053.752.251.850.750.448.747.948.747.946.851.1
Percentage of Assets22.222.422.422.421.321.320.820.820.721.320.919.919.519.119.118.618.618.218.317.917.617.917.617.417.116.816.717.517.017.316.917.016.116.215.416.015.515.615.915.915.517.0
Percentage of Assets lnt:Ipl40.540.540.239.937.938.237.437.037.938.638.436.336.435.635.634.334.033.433.532.632.933.432.732.332.031.631.232.832.232.932.432.731.331.430.530.429.629.730.230.429.531.9

lnt:Wpl


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-312011-12-31
Value272526452478248224512436236323242185217921492146205519001881173018321793178317671770173317251712171116771670164215831442
Percentage of StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest45.344.342.142.042.742.743.745.044.644.644.945.045.242.942.942.645.144.945.045.044.945.445.447.047.147.447.347.248.245.6
Percentage of Assets15.215.014.014.214.214.414.214.113.613.913.914.114.113.313.312.914.114.114.214.114.114.114.314.214.814.715.014.814.714.9
Percentage of Assets lnt:Wpl38.338.335.936.836.937.236.336.834.235.334.935.534.833.032.732.733.933.533.633.533.633.333.433.434.934.334.734.233.235.7

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value3.03.02.02.02.52.52.52.42.42.42.42.42.32.32.32.32.32.32.32.32.31.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.11.1
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStockValue dei:LegalEntity

lnt:Ipl


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value333333333333333333333333333333333333333333333333333333333333333333333333333333333333
Percentage of CommonStockValue1100.01100.01650.01650.01336.01336.01336.01391.71391.71391.71391.71391.71452.21452.21452.21452.21452.21452.21452.21452.21452.23036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.43036.4
Percentage of Assets0.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.20.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.40.40.4
Percentage of Assets lnt:Ipl0.30.30.30.30.30.40.40.40.40.40.40.40.40.40.40.40.40.50.50.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.70.70.70.70.7

lnt:Wpl


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value666666666666666666666666666666666666666666666666666666666666666666666666666666666666
Percentage of CommonStockValue2200.02200.03300.03300.02648.02648.02648.02758.32758.32758.32758.32758.32878.32878.32878.32878.32878.32878.32878.32878.32878.36018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.26018.2
Percentage of Assets0.40.40.40.40.40.40.40.40.40.40.40.40.50.50.50.50.50.50.50.50.50.50.50.50.50.50.50.60.60.60.60.60.60.60.60.60.70.70.70.70.70.7
Percentage of Assets lnt:Wpl0.91.01.01.01.01.01.01.01.01.11.11.11.11.11.21.21.21.21.31.21.21.21.31.31.31.31.31.31.41.41.41.41.41.41.41.61.61.61.61.71.71.7

Additional Paid In Capital Common Stock

us-gaap:AdditionalPaidInCapitalCommonStock

us-gaap:AdditionalPaidInCapitalCommonStock


Additional
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value27222712270426932683267424452236210821002045203819471851184518381830169916931686168116731663165616491631150915081507150615071506150615041511151215111510151015091509150715061499
Percentage of AdditionalPaidInCapitalCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets15.215.415.315.415.515.814.613.513.113.413.313.313.313.013.013.013.312.612.712.913.313.413.313.213.413.512.513.013.213.613.613.713.814.014.014.815.215.715.615.916.216.016.216.6

us-gaap:AdditionalPaidInCapitalCommonStock dei:LegalEntity

lnt:Ipl


Additional
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value280227522752269325222447234723222322232222222027192717971797169716971597159714721447144714071342134212421242124212121182115211221092106210371007977927927873903974
Percentage of AdditionalPaidInCapitalCommonStock102.9101.5101.8100.094.091.596.0103.8110.2110.6108.799.599.097.197.492.492.894.094.487.486.186.584.781.181.476.282.482.480.578.576.574.572.670.668.766.664.761.461.457.959.864.6
Percentage of Assets15.615.615.515.414.614.514.114.014.414.814.413.313.212.612.712.012.411.911.911.311.411.611.310.710.910.310.310.710.710.610.410.210.09.99.69.89.89.69.69.29.710.5
Percentage of Assets lnt:Ipl28.528.327.927.326.126.025.325.026.326.926.424.224.623.623.622.122.621.821.920.621.321.621.019.820.419.419.220.120.220.319.919.719.519.219.018.718.818.318.217.618.519.7

lnt:Wpl


Additional
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value1669158414591459145914591434140913091309130913091259110911091059101910191019959959959959959959959959959959959959959959959959869869869869869869844
Percentage of AdditionalPaidInCapitalCommonStock61.358.454.054.254.454.658.663.062.162.364.064.264.759.960.157.655.760.060.256.957.057.357.757.958.258.863.563.663.663.763.663.663.763.863.557.557.557.657.557.657.656.0
Percentage of Assets9.39.08.28.38.48.68.68.58.18.38.58.68.67.87.87.57.47.67.67.47.67.77.77.67.87.97.98.38.48.68.68.78.88.98.98.58.79.09.09.29.39.1
Percentage of Assets lnt:Wpl23.522.921.121.621.922.322.022.320.521.221.321.721.319.319.318.918.719.119.317.717.918.118.218.218.418.618.719.519.619.920.019.920.120.320.120.420.921.421.522.122.421.7

Common Stocks Including Additional Paid In Capital

us-gaap:CommonStocksIncludingAdditionalPaidInCapital us-gaap:ConsolidatedEntities

us-gaap:CommonStocksIncludingAdditionalPaidInCapital

srt:ParentCompany


Common
Period End2020-12-312019-12-312018-12-31
Value270624482048
Percentage of CommonStocksIncludingAdditionalPaidInCapital100.0100.0100.0
Percentage of Assets15.314.713.3
Percentage of Assets srt:ParentCompany39.839.936.4

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:RetainedEarningsAccumulatedDeficit


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value31063063299430262873283327652739259725872545253924122389234623242228220521772181211620982068209719791973193819341837183217801767166116481630161215111495151015001425142113941281
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets17.317.416.917.316.616.816.616.616.116.516.516.616.516.816.516.516.216.416.316.716.716.716.616.716.116.316.016.716.116.516.016.115.315.415.115.715.215.515.615.815.315.115.014.2

us-gaap:RetainedEarningsAccumulatedDeficit dei:LegalEntity

lnt:Ipl


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value9449579791004914914890887788785774777692683678701619615617631555561554614532550537552485501493507429439448456384398433456358382
Percentage of RetainedEarningsAccumulatedDeficit30.431.232.733.231.832.332.232.430.430.430.430.628.728.628.930.227.827.928.429.026.326.826.829.326.927.927.828.626.427.427.728.725.926.727.528.325.426.728.730.425.127.4
Percentage of Assets5.35.45.55.75.35.45.35.44.95.05.05.14.74.84.85.04.54.64.64.84.44.54.44.94.34.64.54.84.34.54.44.63.94.14.24.53.94.14.54.83.94.1
Percentage of Assets lnt:Ipl9.69.89.910.29.59.79.69.58.99.19.29.38.89.08.99.18.38.48.58.88.28.48.39.18.18.68.38.98.18.68.58.97.77.98.28.57.47.98.59.27.37.7

lnt:Wpl


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value990995953957926910863849810804774771730725706684666659645788753743731734698691678679647642617608575570557545517510507494471459
Percentage of RetainedEarningsAccumulatedDeficit31.932.531.831.632.232.131.231.031.231.130.430.430.330.430.129.429.929.929.736.235.635.435.335.035.335.035.035.135.235.134.734.434.734.634.233.834.234.133.632.933.132.9
Percentage of Assets5.55.75.45.55.45.45.25.15.05.15.05.15.05.15.04.84.84.94.86.15.95.95.95.85.75.75.65.95.75.85.65.55.35.35.25.35.25.35.25.25.14.9
Percentage of Assets lnt:Wpl13.914.413.814.213.913.913.313.512.713.012.612.812.412.612.312.212.212.412.214.614.114.013.914.013.413.413.213.813.213.312.812.612.012.111.712.812.512.612.512.612.211.8

us-gaap:RetainedEarningsAccumulatedDeficit us-gaap:ConsolidatedEntities

srt:ParentCompany


Retained
Period End2020-12-312019-12-312018-12-31
Value299627662545
Percentage of RetainedEarningsAccumulatedDeficit100.1100.0100.0
Percentage of Assets16.916.616.5
Percentage of Assets srt:ParentCompany44.145.045.2

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value-1000000.0-1000000.0-1000000.0-1000000.0-600000.02000000.01300000.01000000.01000000.02400000.01700000.0-200000.0100000.0-500000.0-500000.0-400000.0-400000.0-400000.0-400000.0-400000.0-400000.0-400000.0-400000.0-600000.0-600000.0-600000.0-600000.0-200000.0-200000.0-200000.0-200000.0-800000.0-800000.0-800000.0-800000.0-800000.0-800000.0-800000.0-800000.0-600000.0-600000.0-1400000.0-1400000.0-1400000.0
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-0.0-0.0-0.0-0.0-0.00.00.00.00.00.00.0-0.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0

Minority Interest

us-gaap:MinorityInterest us-gaap:EquityMethodInvestmentNonconsolidatedInvestee

us-gaap:MinorityInterest

us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees


Minority
Period End2020-12-312019-12-31
Value192208
Percentage of MinorityInterest100.0100.0
Percentage of Assets1.11.2
Percentage of Assets us-gaap:EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvestees0.00.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value62145651161591601512329518185507-154.3891003811683332051442812281751782023141273151542938721922419824026112421590145205261289216290189
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue7.616.18.012.620.917.517.223.512.118.39.854.6-18.99.711.742.122.039.125.815.637.327.123.819.828.235.115.937.420.630.810.625.431.323.132.129.418.028.110.214.325.127.734.722.739.121.3

us-gaap:NetCashProvidedByUsedInOperatingActivities dei:LegalEntity

lnt:Ipl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value63-45.0-25.0-58.2522534491276-43.9365-261.5-65.2-30.620291176105-15.3155116672312417032167100105-27.1861086511896-1.778526911612817093
Percentage of NetCashProvidedByUsedInOperatingActivities101.6-31.0-38.5-50.032.715.722.821.312.842.4-51.372.1169.5-73.0-30.653.154.552.851.3-10.655.251.038.113.261.454.125.553.165.036.0-30.839.148.332.849.336.8-1.436.358.747.456.749.159.043.2
Percentage of RegulatedAndUnregulatedOperatingRevenue7.7-5.0-3.1-6.36.82.73.95.01.67.8-5.039.4-32.0-7.1-3.622.312.020.613.2-1.720.613.89.12.617.319.04.019.913.411.1-3.39.915.17.615.810.8-0.210.26.06.814.213.620.59.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl13.8-9.2-5.6-10.512.14.86.98.32.813.8-8.966.8-55.1-12.4-6.538.421.839.124.3-3.037.825.416.84.732.534.87.535.224.420.0-5.917.428.313.630.219.3-0.519.613.114.331.226.940.917.5

lnt:Wpl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value5214864145108148631518612211111984141104131841458218712712373145721575813010612867131119105871578794471109717378127
Percentage of NetCashProvidedByUsedInOperatingActivities83.9102.198.5125.367.892.542.165.289.867.5130.423.6-54.6158.7104.534.450.143.639.9130.545.454.142.081.935.750.145.941.369.143.876.359.653.353.136.560.470.543.952.875.947.366.427.258.7
Percentage of RegulatedAndUnregulatedOperatingRevenue6.416.47.815.814.216.27.215.310.912.412.812.910.315.512.214.511.017.110.320.316.914.610.016.210.117.67.315.514.213.58.115.116.712.311.717.812.712.35.410.811.818.39.413.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl15.237.517.941.534.639.517.640.726.429.430.232.325.537.127.935.525.237.023.347.338.232.922.338.122.339.716.336.832.931.418.936.337.428.525.441.927.726.613.829.629.744.622.634.4

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-152.0-38.0-272.0-286.7-212.7-179.6-426.2-254.1-242.2-364.8-251.1-637.2-93.3-85.2-424.0-445.9-322.8-303.6-414.7-271.0-280.8-220.0-306.2-142.7-219.4-250.9-277.3-271.4-192.2-176.8-241.5-191.0-202.5-119.7-637.8-195.9-186.7-135.1-145.7-165.3-107.8-233.3-260.0-210.9-163.4-232.2
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue-18.6-4.2-33.3-31.2-27.9-19.6-48.4-25.7-30.7-37.0-28.7-68.6-11.4-9.3-49.5-49.2-42.2-35.6-52.0-29.3-37.2-26.1-41.4-15.9-30.6-28.0-34.5-32.2-25.6-18.6-29.0-22.0-28.2-13.9-84.9-22.1-27.0-17.6-16.6-16.2-13.2-24.7-31.2-22.2-22.0-26.1

us-gaap:NetCashProvidedByUsedInInvestingActivities dei:LegalEntity

lnt:Ipl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.098-99.0-76.8-72.3-52.9-182.9-129.6-132.7-221.8-100.5-489.310455-212.8-187.7-169.6-136.3-258.2-143.9-168.3-123.2-192.5-34.2-128.9-156.3-176.2-180.1-99.8-96.6-133.5-100.0-106.6-83.2-120.1-90.8-58.9-61.4-68.4-72.349-109.8-118.8-95.2
Percentage of NetCashProvidedByUsedInInvestingActivities-0.0-257.936.426.834.029.542.951.054.860.840.076.8-112.3-65.350.242.152.544.962.353.159.956.062.924.058.862.363.566.451.954.655.352.452.669.518.846.431.545.446.943.7-46.347.145.745.1
Percentage of RegulatedAndUnregulatedOperatingRevenue0.010.9-12.1-8.3-9.5-5.8-20.8-13.1-16.8-22.5-11.5-52.712.86.1-24.9-20.7-22.2-16.0-32.4-15.6-22.3-14.6-26.0-3.8-18.0-17.4-21.9-21.4-13.3-10.1-16.0-11.5-14.8-9.7-16.0-10.2-8.5-8.0-7.8-7.16.1-11.6-14.3-10.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl0.020.0-22.3-13.9-16.7-10.2-36.8-21.7-30.1-40.0-20.3-89.422.110.6-45.1-35.6-40.4-30.3-59.4-27.9-40.9-26.9-48.3-6.8-33.7-32.0-40.9-37.8-24.2-18.3-28.8-20.2-27.8-17.4-30.5-18.2-16.3-15.4-16.9-14.913.3-23.0-28.5-17.8

lnt:Wpl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-134.0-119.0-148.0-205.2-135.3-124.5-222.3-116.9-97.7-120.3-138.8-143.2-196.8-128.7-195.5-147.8-173.1-149.3-152.2-121.1-114.2-91.4-98.6-97.6-83.6-78.4-86.3-82.7-80.6-70.5-83.5-88.1-88.2-76.1-497.7-79.1-69.8-63.6-63.0-71.1-47.0-124.3-136.0-114.0
Percentage of NetCashProvidedByUsedInInvestingActivities88.2313.254.471.663.669.352.246.040.333.055.322.5210.9151.146.133.153.649.236.744.740.741.532.268.438.131.231.130.541.939.934.646.143.663.678.040.437.447.143.243.043.653.352.354.1
Percentage of RegulatedAndUnregulatedOperatingRevenue-16.4-13.2-18.1-22.3-17.7-13.6-25.3-11.8-12.4-12.2-15.9-15.4-24.1-14.0-22.8-16.3-22.6-17.5-19.1-13.1-15.1-10.8-13.3-10.9-11.7-8.7-10.7-9.8-10.7-7.4-10.0-10.2-12.3-8.9-66.3-8.9-10.1-8.3-7.2-7.0-5.7-13.2-16.3-12.0
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl-39.3-30.1-41.5-58.5-43.3-33.2-61.4-31.4-30.0-29.0-37.6-38.6-59.5-33.7-52.2-39.9-51.7-38.0-43.2-30.5-34.2-24.3-29.8-25.5-25.7-19.7-24.0-23.3-24.8-17.2-23.5-24.4-27.6-20.6-144.2-21.0-22.1-17.9-18.3-19.0-14.4-32.0-39.1-30.8

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value88-145.069154204609347302176-56.7365231-9.834266153-29.91322050.8-9.3-3.149-26.0-23.1195-49.539-112.1145-22.6-64.1-46.7377-54.962-60.421-12.0-146.7-61.2-7.0-39.6-95.77.9
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue10.8-16.18.416.826.76.610.64.838.317.8-6.539.428.4-1.140.07.320.0-3.516.622.20.1-1.1-0.45.5-3.6-2.624.3-5.95.2-11.817.5-2.6-8.9-5.450.2-6.29.0-7.92.4-1.2-17.9-6.5-0.8-4.2-12.90.9

us-gaap:NetCashProvidedByUsedInFinancingActivities dei:LegalEntity

lnt:Ipl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-63.0-92.0-11.011619843-27.5259119139-79.53541558.9242-14.277-39.278234125.3301083.9-16.514411-1.1-7.615815-1.5180.7-2.7404.317-17.7-149.4-20.3-48.7-24.2
Percentage of NetCashProvidedByUsedInFinancingActivities-71.663.4-15.975.597.472.1-29.6547.639.679.3140.297.067.2-90.870.7-21.450.7131.159.1114.31537.5-57.0-987.1220.2-15.071.473.9-23.8-2.86.8108.9-67.32.3-39.00.24.964.6-7.181.8147.5101.833.2695.761.1
Percentage of RegulatedAndUnregulatedOperatingRevenue-7.7-10.2-1.312.726.04.8-3.126.215.214.1-9.138.219.11.028.3-1.610.2-4.69.825.41.60.64.112.00.5-1.818.01.4-0.1-0.819.11.8-0.22.10.1-0.35.80.62.0-1.7-18.2-2.1-5.8-2.5
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl-13.8-18.8-2.521.146.08.4-5.543.427.225.1-16.164.832.81.751.3-2.718.5-8.718.045.43.01.27.721.41.0-3.433.52.5-0.3-1.434.33.1-0.43.80.2-0.511.21.14.3-3.7-39.9-4.3-11.7-4.5

lnt:Wpl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value83-30.085587.7-5.4153-189.4171-6.42826111-31.311016891.668-64.3-11.8-31.3-10.6-61.2-30.9-35.272-51.7-24.7-53.810-38.8-37.5-21.6394-64.9-17.4-31.3-5.3-29.4-37.9-48.222-5.3
Percentage of NetCashProvidedByUsedInFinancingActivities94.320.7123.237.93.8-9.0165.1-400.456.6-3.6-50.87.348.1319.432.425.558.3-5.451.8-31.3-1475.0336.6341.9-124.6118.8152.436.9104.4-62.848.07.1171.758.546.3104.6118.2-27.951.8-24.8245.025.878.8-314.313.4
Percentage of RegulatedAndUnregulatedOperatingRevenue10.2-3.310.46.41.0-0.617.4-19.121.7-0.63.32.913.6-3.413.01.911.70.28.6-7.0-1.6-3.7-1.4-6.8-4.3-3.99.0-6.1-3.3-5.61.2-4.5-5.2-2.552.5-7.3-2.5-4.1-0.6-2.9-4.6-5.12.6-0.6
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl24.3-7.623.816.72.5-1.442.4-50.952.6-1.57.87.233.6-8.229.64.626.70.419.5-16.2-3.5-8.3-3.2-16.0-9.5-8.920.0-14.6-7.6-13.12.9-10.8-11.7-5.8114.3-17.2-5.5-8.8-1.5-7.8-11.6-12.46.3-1.4

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value-2.0-38.0-138.0-15.715040-182.025156-7.7-222.3235-16.2-5.7183.0-2.81.9
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue-0.2-4.2-16.9-1.719.84.5-20.72.619.8-0.8-25.425.4-2.0-0.62.20.3-0.40.2

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect dei:LegalEntity

lnt:Ipl


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value0.0-39.0-135.0-18.217815-176.0178-0.5-5.5-223.9231-1.2-0.7-0.22.6-0.20.8
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect-0.0102.697.8115.9118.438.496.7701.6-0.371.4100.798.07.412.3-1.186.77.142.1
Percentage of RegulatedAndUnregulatedOperatingRevenue0.0-4.3-16.5-2.023.41.7-20.018.1-0.1-0.6-25.624.9-0.1-0.1-0.00.3-0.00.1
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl0.0-8.0-30.5-3.341.33.0-35.430.0-0.1-1.0-45.342.2-0.3-0.1-0.00.5-0.00.2

lnt:Wpl


Cash
Period End2021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value-1.01.0-0.8-19.518-5.2-154.9159-4.51.53.1-1.3-18.320-2.00.7-2.1
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect2.6-0.75.1-12.944.72.9-607.5102.258.4-0.71.38.0321.1110.7-66.7-25.0-110.5
Percentage of RegulatedAndUnregulatedOperatingRevenue-0.10.1-0.1-2.62.0-0.6-15.620.2-0.50.20.3-0.2-2.02.4-0.20.1-0.2
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl-0.30.3-0.2-6.24.9-1.4-41.649.0-1.10.40.8-0.4-4.85.5-0.50.2-0.5

Depreciation Depletion And Amortization

us-gaap:DepreciationDepletionAndAmortization

us-gaap:DepreciationDepletionAndAmortization


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value165164161155152146143143142136130129
Percentage of DepreciationDepletionAndAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DepreciationDepletionAndAmortization dei:LegalEntity

lnt:Ipl


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value939492898885838382777473
Percentage of DepreciationDepletionAndAmortization56.457.357.157.558.358.758.058.257.856.356.957.3

lnt:Wpl


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value706968646259595859585554
Percentage of DepreciationDepletionAndAmortization42.442.142.241.740.840.441.141.041.442.842.341.9

Increase Decrease In Accounts Receivable

us-gaap:IncreaseDecreaseInAccountsReceivable

us-gaap:IncreaseDecreaseInAccountsReceivable


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1391261521187811911215978121150-182.636014743-25.1-11.2-36.520411147-25.122-27.1-6.647-48.5-103.25536-3.63.512-10.43.19.9-63.94.677-28.20.46.741-41.5-23.1
Percentage of IncreaseDecreaseInAccountsReceivable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInAccountsReceivable dei:LegalEntity

lnt:Ipl


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value1371331291189312510115596112140-192.437816620145.5-32.7-6.833-4.837-28.725-19.12.222-17.8-97.2482.919-1.034-1.92.118-18.3-8.120-24.7-10.48.726
Percentage of IncreaseDecreaseInAccountsReceivable98.6105.684.9100.2118.1105.590.397.6123.892.693.7105.4105.2112.947.0-59.0-49.189.6-33.381.4-41.078.5114.3114.570.5-33.348.136.794.287.98.0-536.1-28.6269.018.367.7189.928.6-176.126.887.6-2600.0129.962.5

Increase Decrease In Other Operating Capital Net

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value3524-75.0404410-40.34427-22.0-9.775-10.835-55.9-3.539-18.5-11.6-17.189-44.8-1.532-31.45.8-95.271-36.70.9-50.534-11.63.7-35.254-19.2134.2-17.614-22.022-13.8-47.631
Percentage of IncreaseDecreaseInOtherOperatingCapitalNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet dei:LegalEntity

lnt:Ipl


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-40.064-21.04.832181.11.38.7-43.34.2302.57.92.0-10.411-21.3-12.42439-20.8-17.5-9.0-4.3-12.2-50.618-47.328-14.6129.7-19.3-10.445-35.56.6-2.5-24.211-20.1281.7
Percentage of IncreaseDecreaseInOtherOperatingCapitalNet-114.3266.728.011.873.8184.2-2.72.931.4196.8-43.340.4-23.122.5-3.6297.128.8115.1106.9-143.944.646.41166.7-27.713.7-210.353.225.9128.93177.828.936.3-83.6-521.629.583.4184.947.5-59.5137.580.491.4129.0-12.3

lnt:Wpl


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value50-16.016-1.130-24.8-7.01827-24.1-43.74362-35.4-31.52630-20.7-5.00.7-16.4-4.8-23.332-7.5-29.1-6.617-5.41.1-7.8-3.214-13.8-35.13.916-16.03.25.15.4-15.522-3.0
Percentage of IncreaseDecreaseInOtherOperatingCapitalNet142.9-66.7-21.3-2.769.9-245.517.441.4100.7109.5450.557.4-575.0-100.956.4-762.978.1111.943.1-4.1-18.410.71553.3100.023.9-501.76.925.014.7122.215.4-9.2-123.3-373.099.77.1-83.3-115.176.2-29.037.870.5101.821.7

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value62145651161591601512329518185507-154.3891003811683332051442812281751782023141273151542938721922419824026112421590145205261289216290189
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue7.616.18.012.620.917.517.223.512.118.39.854.6-18.99.711.742.122.039.125.815.637.327.123.819.828.235.115.937.420.630.810.625.431.323.132.129.418.028.110.214.325.127.734.722.739.121.3

us-gaap:NetCashProvidedByUsedInOperatingActivities dei:LegalEntity

lnt:Ipl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value63-45.0-25.0-58.2522534491276-43.9365-261.5-65.2-30.620291176105-15.3155116672312417032167100105-27.1861086511896-1.778526911612817093
Percentage of NetCashProvidedByUsedInOperatingActivities101.6-31.0-38.5-50.032.715.722.821.312.842.4-51.372.1169.5-73.0-30.653.154.552.851.3-10.655.251.038.113.261.454.125.553.165.036.0-30.839.148.332.849.336.8-1.436.358.747.456.749.159.043.2
Percentage of RegulatedAndUnregulatedOperatingRevenue7.7-5.0-3.1-6.36.82.73.95.01.67.8-5.039.4-32.0-7.1-3.622.312.020.613.2-1.720.613.89.12.617.319.04.019.913.411.1-3.39.915.17.615.810.8-0.210.26.06.814.213.620.59.8
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Ipl13.8-9.2-5.6-10.512.14.86.98.32.813.8-8.966.8-55.1-12.4-6.538.421.839.124.3-3.037.825.416.84.732.534.87.535.224.420.0-5.917.428.313.630.219.3-0.519.613.114.331.226.940.917.5

lnt:Wpl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value5214864145108148631518612211111984141104131841458218712712373145721575813010612867131119105871578794471109717378127
Percentage of NetCashProvidedByUsedInOperatingActivities83.9102.198.5125.367.892.542.165.289.867.5130.423.6-54.6158.7104.534.450.143.639.9130.545.454.142.081.935.750.145.941.369.143.876.359.653.353.136.560.470.543.952.875.947.366.427.258.7
Percentage of RegulatedAndUnregulatedOperatingRevenue6.416.47.815.814.216.27.215.310.912.412.812.910.315.512.214.511.017.110.320.316.914.610.016.210.117.67.315.514.213.58.115.116.712.311.717.812.712.35.410.811.818.39.413.4
Percentage of RegulatedAndUnregulatedOperatingRevenue lnt:Wpl15.237.517.941.534.639.517.640.726.429.430.232.325.537.127.935.525.237.023.347.338.232.922.338.122.339.716.336.832.931.418.936.337.428.525.441.927.726.613.829.629.744.622.634.4

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value14617466249136172114228971278720810212396171961036513186993618270996215564110681606780721546938611255579521535248
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RegulatedAndUnregulatedOperatingRevenue17.919.38.127.117.918.813.023.112.312.910.122.412.613.511.218.912.612.18.214.211.411.74.920.39.811.17.818.58.611.68.218.59.49.39.617.410.15.16.912.36.78.46.216.27.15.4

us-gaap:NetIncomeLoss dei:LegalEntity

lnt:Ipl


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312