CNA


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

Table of contents



us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareDiluted

us-gaap:BenefitsLossesAndExpenses
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:DeferredPolicyAcquisitionCostAmortizationExpense
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:IncomeLossFromContinuingOperations

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

us-gaap:IncomeTaxExpenseBenefit

us-gaap:InterestExpense

us-gaap:NetIncomeLoss
us-gaap:StatementEquityComponents

us-gaap:NetInvestmentIncome

us-gaap:OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax
us-gaap:StatementEquityComponents

us-gaap:OtherIncome
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:PolicyholderBenefitsAndClaimsIncurredNet
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:PremiumsEarnedNet
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:RealizedInvestmentGainsLosses

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:Revenues
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:Assets
us-gaap:ConsolidatedEntities

us-gaap:Liabilities
us-gaap:ConsolidatedEntities

us-gaap:LiabilitiesAndStockholdersEquity
us-gaap:ConsolidatedEntities

us-gaap:StockholdersEquity
us-gaap:ConsolidatedEntities
us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents
us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:Cash

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
us-gaap:ConsolidatedEntities
us-gaap:ShortTermInvestments

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:Goodwill
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill
us-gaap:IndefiniteLivedIntangibleAssetsByMajorClass

us-gaap:DeferredTaxAssetsLiabilitiesNet

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:EquitySecuritiesFvNi
us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument
us-gaap:FinancialInstrument

us-gaap:OtherAssets
us-gaap:ConsolidatedEntities

us-gaap:LongTermDebt

us-gaap:LongTermDebtNoncurrent
us-gaap:ConsolidatedEntities
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis
us-gaap:LongtermDebtType

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive

us-gaap:OperatingLeaseLiability

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

us-gaap:StockholdersEquity
us-gaap:ConsolidatedEntities
us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents
us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapitalCommonStock
us-gaap:ConsolidatedEntities

us-gaap:RetainedEarningsAccumulatedDeficit
us-gaap:ConsolidatedEntities

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax
us-gaap:ConsolidatedEntities

us-gaap:TreasuryStockValue
us-gaap:ConsolidatedEntities
us-gaap:StatementEquityComponents
us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DepreciationDepletionAndAmortization

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetIncomeLoss
us-gaap:StatementEquityComponents

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:ProceedsFromIssuanceOfLongTermDebt

us-gaap:RepaymentsOfLongTermDebt

us-gaap:PaymentsOfDividendsCommonStock

us-gaap:PaymentsForRepurchaseOfCommonStock

cna:ChangeInOtherInvestments

cna:ChangeInShortTermInvestments

cna:CostsFromContractWithCustomers
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss
us-gaap:FairValueByAssetClass
us-gaap:FairValueByAssetClass, us-gaap:IncomeStatementLocation
cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome
us-gaap:IncomeStatementLocation

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss
us-gaap:FairValueByAssetClass

cna:IncomeTaxExpenseBenefitOnNetRealizedInvestmentGainsLosses

cna:IncomeTaxExpenseBenefitOnOperatingIncomeLoss
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

cna:Insuranceclaimsandpolicyholdersbenefitsincludingpolicyholdersdividends

cna:InvestmentsandDerivativesRealizedGainLoss

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCtaAndOther

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsAmortizationOfDiscount

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease

cna:LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease

cna:LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease

cna:NetInvestmentIncomeAndGainsLossesOnTradingSecurities
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

cna:NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCasualty
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentOther
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyAndOther
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSpecialty
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWarranty
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReservePropertyEnergyAndMarine
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentOtherProfessionalLiability
us-gaap:StatementBusinessSegments
cna:NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyMarine

cna:NetRealizedInvestmentGainsLosses

cna:NetRealizedInvestmentGainsLossesContinuingAndDiscontinuingOperations
us-gaap:StatementBusinessSegments
cna:NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability

cna:OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

cna:OperatingRevenues
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

cna:OtherInsuranceRelatedExpenses
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

cna:PaymentstoAcquireMarketableSecuritiesEquity
us-gaap:StatementBusinessSegments
cna:PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup

cna:PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup
us-gaap:StatementBusinessSegments

cna:ProceedsfromSaleofMarketableSecuritiesEquity

cna:RealizedGainLossonShortTermInvestments

cna:ReinsurancePremiumsPaid

cna:Retroactivereinsurancebenefitrecognized

cna:RevenuesExcludingInvestmentsAndDerivativesRealizedGainLoss

us-gaap:AccretionAmortizationOfDiscountsAndPremiumsInvestments

us-gaap:ContractWithCustomerLiabilityRevenueRecognized

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleRealizedGain

us-gaap:DebtSecuritiesAvailableForSaleRealizedGainLoss

us-gaap:DebtSecuritiesAvailableForSaleRealizedLoss

us-gaap:DebtSecuritiesRealizedGainLoss
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanInterestCost
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1
us-gaap:StatementEquityComponents
us-gaap:DividendsCommonStockCash
us-gaap:FinancialInstrument
us-gaap:EquitySecuritiesFvNiGainLoss

us-gaap:EquitySecuritiesFvNiRealizedGainLoss

us-gaap:FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss
us-gaap:FairValueByAssetClass
us-gaap:FairValueByAssetClass, us-gaap:IncomeStatementLocation
us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1
us-gaap:IncomeStatementLocation

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss
us-gaap:FairValueByAssetClass

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
us-gaap:FairValueByAssetClass

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales
us-gaap:FairValueByAssetClass

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
us-gaap:FairValueByAssetClass

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3
us-gaap:FairValueByAssetClass

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3
us-gaap:FairValueByAssetClass

us-gaap:GainLossOnSaleOfDerivatives

us-gaap:GrossInvestmentIncomeOperating
us-gaap:FinancialInstrument

us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions

us-gaap:IncreaseDecreaseInAccruedInvestmentIncomeReceivable

us-gaap:IncreaseDecreaseInDeferredPolicyAcquisitionCosts

us-gaap:IncreaseDecreaseInFinancialInstrumentsUsedInOperatingActivities

us-gaap:IncreaseDecreaseInInsuranceLiabilities

us-gaap:IncreaseDecreaseInOtherReceivables

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:InvestmentIncomeInvestmentExpense

us-gaap:LiabilityForFuturePolicyBenefitsPeriodExpense

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1

us-gaap:LossFromCatastrophes
us-gaap:IncomeStatementLocation, us-gaap:RetirementPlanType
us-gaap:NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent

us-gaap:OciBeforeReclassificationsNetOfTaxAttributableToParent
us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax
us-gaap:FinancialInstrument

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax

us-gaap:OtherComprehensiveIncomeLossTaxPortionAttributableToParent1
us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:OtherCostAndExpenseOperating

us-gaap:OtherExpenses
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OtherOperatingActivitiesCashFlowStatement

us-gaap:OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings
us-gaap:FinancialInstrument

us-gaap:PaymentsForLossesAndLossAdjustmentExpense

us-gaap:PaymentsForProceedsFromOtherInvestingActivities

us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt

us-gaap:PaymentsToAcquireLimitedPartnershipInterests

us-gaap:PaymentsToAcquireMortgageNotesReceivable

us-gaap:PolicyholderDividends
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:PremiumDeficiencyTestingExpenseLongDurationContractAmount

us-gaap:ProceedsFromLimitedPartnershipInvestments

us-gaap:ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities

us-gaap:ProceedsFromPaymentsForOtherFinancingActivities

us-gaap:ProceedsFromSaleAndCollectionOfMortgageNotesReceivable

us-gaap:ProceedsFromSaleOfAvailableForSaleSecuritiesDebt

us-gaap:ProvisionForLoanLossesExpensed

us-gaap:ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent
us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:ReclassificationFromAociCurrentPeriodTax
us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:ReinsuranceLossOnUncollectibleAccountsInPeriodAmount
us-gaap:StatementScenario, us-gaap:SubsequentEventType

us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense

us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense

us-gaap:TreasuryStockValueAcquiredCostMethod
us-gaap:StatementEquityComponents

us-gaap:UnusualOrInfrequentItemNetOfInsuranceProceeds
us-gaap:LiabilityForCatastropheClaimsByCatastrophicEvent

cna:Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves

cna:Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements

cna:AnticipatedAmountsDueFromInsuredsRelatedToLossesUnderDeductiblePolicies

cna:CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity

cna:CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities

cna:CarryingValueOfTenLargestLimitedPartnerships

cna:CashAndSecuritiesDepositedAsCollateralForLettersOfCredit

cna:CededClaimAndClaimAdjustmentExpenses

cna:CededFuturePolicyBenefits

cna:CollateralTrustAccountPercentageOfOutstandingReserves

cna:CommitmentsToPurchaseOrFundAdditionalAmounts

cna:CommitmentsToSellVariousPrivatelyPlacedDebtSecurities
us-gaap:ProductOrService
cna:CumulativeamountscededunderAEPLossPortfolioTransfer

cna:DebtSecuritiesAmortizedCost

cna:DeferredTaxAssetsDeferredRetroactiveReinsuranceBenefit

cna:DeferredTaxLiabilitiesDeferredExpenseSoftwareandHardware
us-gaap:ProductOrService
cna:Deferredreinsurancebenefityettoberecognized

cna:DiscountedReservesForUnfundedStructureSettlementsDiscountAmount

cna:DiscountedReservesForUnfundedStructuredSettlements

cna:Discountedreservesforlongtermcareclaimreserves

cna:Discountedreservesforlongtermcareclaimreservesdiscountamount
us-gaap:ProductOrService
cna:FairValueOfCollateralTrustAccountEstablishedByNicoUnderAepLossPortfolioTransfer
us-gaap:RetirementPlanType
cna:FutureCapitalCallCommitments

cna:IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships

cna:IncreaseDecreaseEarnedPremiums
us-gaap:ConsolidatedEntities
cna:InvestmentInSubsidiaries

cna:Liabilityforunpaidclaimandclaimadjustmentexpensegross
us-gaap:StatementBusinessSegments
us-gaap:RetirementPlanType
cna:LimitedPartnershipEquityRelatedHedgeFundStrategyPlanAssets
us-gaap:RetirementPlanType
cna:LimitedPartnershipHedgeFundMultiStrategyPlanAssets
us-gaap:RetirementPlanType
cna:LimitedPartnershipHedgeFundStrategyDistressedInvestmentsPlanAssets

cna:LimitedPartnershipInvestments

cna:LimitedPartnershipsInvestedInPrivateDebtAndEquity

cna:MarketableSecuritiesFixedMaturitiesAllowanceForCreditLoss

cna:MarketableSecuritiesFixedMaturitiesAtAmortizedCost

cna:MortgageLoansonRealEstateCommercialandConsumerAllowanceForCreditLoss

cna:NetCaseReserves
us-gaap:StatementBusinessSegments

cna:NetIbnrReserves
us-gaap:StatementBusinessSegments

cna:NonIncomeProducingFixedMaturitySecurities

cna:OperatingLossCarryforwardsNotSubjectToExpiration
us-gaap:IncomeTaxAuthority
cna:OperatingLossCarryforwardsSubjecttoExpiration

cna:OtherInvestedAssetsOverseasDeposit

cna:PercentageOfDistressedInvestmentsLimitedPartnershipHedgeFundStrategies

cna:PercentageOfEquityRelatedLimitedPartnershipHedgeFundStrategies

cna:PercentageOfFixedIncomeLimitedPartnershipHedgeFundStrategies

cna:PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments
us-gaap:RetirementPlanType

cna:PercentageOfLimitedPartnershipsReportedOnCurrentBasis

cna:PercentageOfLimitedPartnershipsReportedOnOneMonthLag

cna:PercentageOfMultistrategyApproachLimitedPartnershipHedgeFundStrategies

cna:PercentageOfOutstandingReserves

cna:ReductionOfNetUnrealizedGainsOnInvestmentsIncludedInAOCIDueToShadowAdjustments

cna:RetroactiveReinsuranceAgreementAmountAvailable

cna:RetroactiveResinuranceAgreementAmountRemaining

cna:ShorttermInvestmentsandOther
us-gaap:FairValueByFairValueHierarchyLevel

cna:StatutoryAccountingPracticesStatutoryAmountAvailableforDividendPaymentsBeforeConsiderationofStatutoryDividendsPaidintheprecedingtwelvemonths
us-gaap:TaxPeriod
cna:TaxCreditCarryforwardSubjectToExpirationAmount

cna:VoluntaryReinsuranceRecoverableGross
cna:CreditRating

us-gaap:AccruedInvestmentIncomeReceivable

us-gaap:AssetsFairValueDisclosure
us-gaap:FairValueByAssetClass, us-gaap:ValuationTechnique
us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleDebtSecuritiesAmortizedCostBasis
us-gaap:FinancialInstrument

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost

us-gaap:AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue

us-gaap:AvailableForSaleSecuritiesDebtSecurities
us-gaap:FinancialInstrument

us-gaap:CapitalRequiredForCapitalAdequacyToRiskWeightedAssets

us-gaap:ContractWithCustomerAssetNet
us-gaap:CapitalizedContractCost
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:ContractWithCustomerLiability
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:DebtInstrumentUnamortizedDiscount

us-gaap:DebtSecurities
us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLoss
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLoss
us-gaap:FinancialInstrument
us-gaap:DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleExcludingAccruedInterest
us-gaap:FinancialInstrument
us-gaap:Range, us-gaap:MeasurementInputType, us-gaap:ValuationTechnique
us-gaap:DebtSecuritiesAvailableForSaleMeasurementInput

us-gaap:DebtSecuritiesAvailableForSaleUnrealizedLossPosition
us-gaap:FinancialInstrument

us-gaap:DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
us-gaap:FinancialInstrument

us-gaap:DeferredIncomeTaxAssetsNet

us-gaap:DeferredIncomeTaxLiabilities

us-gaap:DeferredPolicyAcquisitionCosts
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:DeferredTaxAssetsGross

us-gaap:DeferredTaxAssetsOther

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAllowanceForDoubtfulAccounts

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsLossReserves

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsUnearnedPremiumsReserve

us-gaap:DeferredTaxLiabilitiesDeferredExpenseDeferredPolicyAcquisitionCost

us-gaap:DeferredTaxLiabilitiesInvestments

us-gaap:DeferredTaxLiabilitiesOther

us-gaap:DeferredTaxLiabilitiesOtherComprehensiveIncome
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedBenefitObligation
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmountsRecognizedInBalanceSheet
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanBenefitObligation
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanFundedStatusOfPlan
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear

us-gaap:DerivativeFairValueOfDerivativeLiability

us-gaap:DerivativeNotionalAmount
us-gaap:ConsolidatedEntities
us-gaap:DueFromAffiliates

us-gaap:DueFromRelatedParties
us-gaap:RelatedPartyTransactionsByRelatedParty

us-gaap:DueToRelatedPartiesCurrentAndNoncurrent
us-gaap:RelatedPartyTransactionsByRelatedParty

us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized

us-gaap:EquitySecuritiesFvNiCost

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
us-gaap:FairValueByAssetClass

us-gaap:FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMaximumAmountAvailable

us-gaap:FederalHomeLoanBankStock
us-gaap:FinancialInstrument
us-gaap:FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableOriginatedInCurrentFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear
us-gaap:FinancialInstrument
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear
us-gaap:FinancialInstrument

us-gaap:FiniteLivedIntangibleAssetsAccumulatedAmortization
us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFive

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFour

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearThree

us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo

us-gaap:FiniteLivedIntangibleAssetsGross
us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:FundsHeldUnderReinsuranceAgreementsLiability
us-gaap:SubsequentEventType
us-gaap:GuaranteeObligationsByNature
us-gaap:GuaranteeObligationsMaximumExposure

us-gaap:IntangibleAssetsGrossExcludingGoodwill
us-gaap:FinancialInstrument
us-gaap:InterestReceivable

us-gaap:Investments

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths

us-gaap:LiabilitiesFairValueDisclosure
us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:LiabilityForClaimsAndClaimsAdjustmentExpense
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:LiabilityForFuturePolicyBenefits
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount
us-gaap:StatementBusinessSegments

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseOpeningBalanceAdjustments

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseReportedClaimsAmount
us-gaap:StatementBusinessSegments

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree

us-gaap:MinimumNetWorthRequiredForCompliance
dei:LegalEntity, us-gaap:Ownership
us-gaap:MinorityInterestOwnershipPercentageByParent

us-gaap:MortgageLoansOnRealEstateCommercialAndConsumerNet
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis
us-gaap:FairValueByMeasurementBasis
cna:DebtServiceCoverage, us-gaap:FinancialInstrument, us-gaap:LoanToValue
us-gaap:NotesReceivableGross
us-gaap:FinancialInstrument
us-gaap:IncomeTaxAuthority
us-gaap:OperatingLossCarryforwards

us-gaap:OtherInvestments

us-gaap:OtherLiabilities
us-gaap:ConsolidatedEntities

us-gaap:OtherLiabilitiesFairValueDisclosure
us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:OtherShortTermInvestments
us-gaap:RetirementPlanType
us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent

us-gaap:PremiumsReceivableAllowanceForDoubtfulAccounts

us-gaap:PremiumsReceivableAtCarryingValue

us-gaap:PremiumsReceivableGross
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:ReinsuranceRecoverables
us-gaap:CededCreditRisk

us-gaap:ReinsuranceRecoverablesAllowance

us-gaap:ReinsuranceRecoverablesGross
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:ReinsuranceRecoverablesOnPaidLossesGross

us-gaap:ReinsuranceRecoverablesOnUnpaidLossesGross
us-gaap:StatementBusinessSegments

us-gaap:RetainedEarningsUndistributedEarningsFromEquityMethodInvestees

us-gaap:RevenueRemainingPerformanceObligation

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimAdjustmentExpenseOtherReconcilingItem
us-gaap:ProductOrService, us-gaap:StatementBusinessSegments
us-gaap:ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense
us-gaap:StatementBusinessSegments
us-gaap:StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrant
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDeferredPolicyAcquisitionCosts
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrant
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDiscountDeductedFromReserves
us-gaap:Range, us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrant
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersInterestRateAtWhichDiscountComputed
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrant
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersReservesForUnpaidClaimsAndClaimsAdjustmentExpense
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrant
us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersUnearnedPremiums

us-gaap:TaxCreditCarryforwardAmount
us-gaap:IncomeTaxAuthority
us-gaap:FinancialInstrument
us-gaap:TradingSecuritiesDebt
us-gaap:FinancialInstrument
us-gaap:TradingSecuritiesDebtAmortizedCost

us-gaap:UnearnedPremiums
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:ValuationAllowancesAndReservesType
us-gaap:ValuationAllowancesAndReservesBalance

us-gaap:WorkersCompensationDiscountAmount

us-gaap:WorkersCompensationLiabilityCurrentAndNoncurrent

Plots across concepts


IncomeStatement
Other Comprehensive Income Loss Net Of Tax
Expenses
Interest Expense
Balance Sheet
Goodwill
Assets
Operating Lease Right Of Use Asset
Current Assets
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents
NonCurrent Assets
Deferred Income Tax Assets Net
PropertyPlantAndEquipmentNet
Property Plant And Equipment Net
Liabilities
Operating Lease Liability
Noncurrent Liabilities
Long Term Debt Noncurrent
Stockholders Equity
Treasury Stock Value
CashFlow
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInOperatingActivities
Net Income Loss
NetCashProvidedByUsedInInvestingActivities
Net Cash Provided By Used In Investing Activities
NetCashProvidedByUsedInFinancingActivities
Net Cash Provided By Used In Financing Activities
Shares
Weighted Average Number Of Shares Outstanding Basic
DividendsAndRepurchase
Payments For Repurchase Of Common Stock
LesseeOperatingLeaseLiabilityPaymentsDue
Lessee Operating Lease Liability Payments Due Year Four

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:WeightedAverageNumberOfDilutedSharesOutstanding ▁█272.8272.9NA272.3272.0271.5NA272.6272.4272.6NA272.5272.4272.4NA272.1271.9271.7NA271.2270.9270.9NA270.8270.70.0NA270.6270.6270.5NA270.2270.1269.9NA269.8269.8269.7NA269.6269.6269.5NA269.2269.3NA
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic ▄▄271.9271.9NA271.7271.5271.5NA271.6271.6271.6NA271.6271.5271.4NA271.2271.1270.7NA270.5270.5270.3NA270.3270.30.0NA269.9269.9269.8NA269.7269.7269.5NA269.4269.4269.3NA269.3269.3269.2NA269.2269.1NA
us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount ▁█0.0010.12NA0.0090.9151.015NA0.0010.0010.0NA0.0010.4450.009NA0.0010.0010.148NA0.1750.1780.18NA0.1060.2380.182NA0.180.180.11NA0.110.1140.335NA0.6930.6220.668NA1.20.9311.0NANANANA
us-gaap:EarningsPerShareBasic █▇█▅▅▁▆▄▆▇▁▇▆▇▆▄▆▆▆▇▅▃▁▅▄▆▅▅▆▂▆▆▅▆▂▆▅1.351.151.420.790.56-0.231.00.391.031.26-0.311.240.991.070.820.531.010.960.891.270.770.25-0.260.660.510.860.730.790.990.050.821.010.720.93-0.0400000000000000360.820.62NA0.710.280.46NANANANANA
us-gaap:EarningsPerShareDiluted █▇█▅▄▁▆▄▆▇▁▇▆▇▆▄▆▆▆▇▅▃▁▅▄▆▅▅▆▂▆▆▅▆▂▆▅1.351.141.420.790.55-0.231.00.391.021.25-0.311.230.991.070.820.531.00.960.891.260.770.24-0.260.660.510.860.730.790.980.050.821.010.720.93-0.0299999999999998050.820.62NA0.710.280.46NANANANANA
  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
  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:BenefitsLossesAndExpenses █▇▇██▆▇█▅▅▇▅▅▅▃▅▃▃▄▃▃▄▇▂▄▃▄▄▄▄▆▄▅▄▇▄▃▃▃▃▃▃▁█▁2567.02488.02453.02570.02584.02380.02442.02558.02268.02276.02517.02220.02244.02189.02038.02211.01996.01987.02073.01958.02060.02138.02430.01920.02163.02039.02126.02118.02076.02165.02314.02129.02217.02140.02470.02152.02016.02037.02020.02051.02019.01984.01822.02530.01787.0NA
us-gaap:ComprehensiveIncomeNetOfTax ▆▃▆▆█▁▅▅▆▇▄▅▄▄▅▅▅▅▄▅▆▅▃▄▄▅▄▄▆▅▆▅▃▅▃▆▅▆▄▅▅▅▃▆▆690.0-304.0779.0470.01375.0-1182.0185.0126.0722.0896.0-205.0184.065.0-125.0148.0219.0396.0341.0-169.0370.0475.0325.0-445.095.0-140.0254.0-175.024.0537.0263.0550.0259.0-407.0146.0-308.0484.0269.0534.0-218.0231.0422.0309.0-549.0645.0684.0NA
us-gaap:DeferredPolicyAcquisitionCostAmortizationExpense ▂▂▃▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁█▂▁▁▂▂▂▂▂▂▂▂▂▂▁▁▂▂▂▁▂▂▂357.0359.0364.0360.0342.0344.0358.0345.0338.0342.0343.0337.0359.0296.0307.0309.0312.0305.0309.0314.0305.0307.0604.0319.0314.0303.0321.0332.0335.0329.0358.0341.0335.0328.0337.0333.0309.0295.0359.0356.0350.0297.0349.0351.0345.0NA
us-gaap:IncomeLossFromContinuingOperations █▇█▆▅▂▆▄▆▇▁▇▆▇▆▅▆▆▆▇▆▄▂▅▅▆▅▆▆▆▆▆▅▆▃▆▅▆▅▄▄▆▇▁▇368.0312.0387.0213.0151.0-61.0273.0107.0278.0342.0-84.0336.0270.0291.0223.0144.0272.0260.0241.0343.0209.066.0-70.0178.0138.0233.0198.0209.0261.0220.0235.0271.0190.0241.0-9.0221.0166.0250.0190.075.0126.0221.0302.0-118.0282.0NA
us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest █▇█▆▅▂▆▄▇▇▂▇▆▇▇▅▇▇▆█▆▃▁▅▅▆▆▆▇▆▆▇▆▇▂▆▅▇▅▄▅▆█▁462.0378.0478.0250.0182.0-89.0335.0127.0342.0419.0-114.0402.0330.0346.0410.0187.0370.0343.0317.0475.0288.057.0-161.0233.0164.0313.0252.0293.0364.0298.0299.0375.0276.0363.0-36.0314.0230.0364.0239.0124.0176.0331.0476.0-167.0NANA
us-gaap:IncomeTaxExpenseBenefit ▆▅▆▄▄▃▅▄▅▅▃▅▅▅█▄▆▅▅▇▅▃▁▅▄▅▅▅▆▅▅▆▅▆▃▆▅▆▄▅▄▆▇▂▇94.066.091.037.031.0-28.062.020.064.077.0-30.066.060.055.0187.043.098.083.076.0132.079.0-9.0-91.055.026.080.054.084.0103.078.078.0103.082.0113.0-27.093.064.0114.048.049.047.0101.0150.0-64.0145.0NA
us-gaap:InterestExpense ▁▁▁▂▂▂▂▂▃▃▃▃▃▃▄▆▅▆▅▅▄▆▄▅▅▅▇█▇▇▆▆▆▆▆▆▆▆▆▆▆▇▇▅▄29.028.028.032.031.031.031.032.034.034.034.034.035.035.037.041.040.043.040.039.038.042.038.039.039.039.045.048.046.044.041.042.041.042.042.043.043.042.043.043.043.046.044.040.037.0NA
us-gaap:NetIncomeLoss █▇█▆▅▂▆▄▇▇▂▇▆▇▆▅▆▆▆▇▆▄▂▅▅▆▅▆▆▃▆▆▅▆▃▆▅▆▅▄▅▆▇▁▇▆368.0312.0387.0213.0151.0-61.0273.0107.0278.0342.0-84.0336.0270.0291.0223.0144.0272.0260.0241.0343.0209.066.0-70.0178.0138.0233.0198.0213.0267.013.0221.0272.0194.0250.0-9.0221.0166.0250.0190.075.0126.0223.0302.0-140.0283.0245.0
us-gaap:NetInvestmentIncome █▆▇▆▆▁▇▅▆▇▁▅▆▅591.0504.0555.0517.0534.0329.0545.0487.0515.0571.0334.0487.0506.0490.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax ▆▅█▇▆▂▇▄▅▆▃▅▃▆▅▇▇▆▃▄▃▆▄▃▇▁▃▂▇▅▆█▅▃▅▇▄▆12.02.063.037.024.0-77.051.0-29.00.017.0-42.00.0-52.012.06.041.042.011.0-56.0-24.0-48.014.0-39.0-53.049.0-96.0-56.0-73.042.0-8.07.056.0-13.0-61.03.033.0-17.021.0NANANANANANANANA
us-gaap:OtherComprehensiveIncomeLossNetOfTax ▅▃▆▅█▁▄▄▆▆▄▄▄▃▄▅▅▅▃▄▅▅▃▄▄▄▃▄▅▅▅▄▃▄322.0-616.0392.0257.01224.0-1121.0-88.019.0444.0554.0-121.0-152.0-205.0-416.0-75.075.0124.081.0-410.027.0266.0259.0-375.0-83.0-278.021.0-373.0-189.0270.0250.0329.0-13.0-601.0-104.0NANANANANANANANANANANANA
us-gaap:OtherIncome ▁▁▁▁▁▁▁▁▁▁▂▁▁▁▇▇▇▇▇▆▆▆█▆▆▆▆▅▆▆▅▅█▅▆▅▆▅▅▅▅▅▄▅▅6.05.07.06.05.08.09.09.04.09.024.010.06.010.0109.0107.0107.0104.0111.096.0100.097.0121.097.092.097.094.084.093.085.076.078.0129.078.090.076.086.068.080.076.071.067.066.075.075.0NA
us-gaap:PolicyholderBenefitsAndClaimsIncurredNet ▆▅▅▇▇▄▅▇▃▃▆▂▃▃▂▅▂▂▃▁▃▄▃▁▅▃▃▃▄▄▆▄▅▄█▄▃▃▃▄▃▃1539.01500.01483.01611.01636.01419.01479.01607.01346.01351.01587.01306.01321.01333.01249.01475.01275.01289.01336.01195.01335.01404.01373.01198.01466.01335.01346.01351.01437.01443.01579.01408.01515.01425.01717.01430.01342.01378.01351.01399.01367.01363.0NANA1147.0NA
us-gaap:PremiumsEarnedNet █▇▇▇▅▅▆▆▅▄▅▅▄▄▄▄▃▂▃▄▃▃▃▃▃▂▄▄▄▄▆▅▄▄▄▄▂▂▂▃▁▁▂▂▁2035.01962.01977.01953.01850.01869.01911.01890.01824.01803.01859.01853.01815.01785.01803.01806.01734.01645.01728.01767.01730.01699.01748.01751.01735.01687.01785.01810.01811.01806.01882.01825.01800.01764.01784.01781.01668.01649.01661.01732.01595.01615.01647.01645.01608.0NA
 us-gaap:RealizedInvestmentGainsLosses us-gaap:DebtInstrument,us-gaap:LongtermDebtType cna:SeniorNotes5750FaceAmount400DueAugust152021,us-gaap:SeniorNotesNANA-40.020.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax ▁▁█▁▁▁█▁▁▁▇▁▇▇▇▇▇▆▇▇▆▆▆▆▆▆▇▇▇▇▇▇▇▇▇▇▆▇▆▆▆▆▆▇▆▆359.0338.02931.0317.0308.0301.02777.0292.0285.0281.02403.0258.02574.02535.02448.02398.02366.02330.02390.02433.02348.02195.02269.02153.02327.02352.02378.02411.02440.02463.02613.02504.02493.02503.02434.02466.02246.02401.02259.02175.02198.02315.02298.02363.02233.02315.0
us-gaap:Revenues █▇▇▆▆▂▆▅▅▅▃▅▄▄▃▃▃▂▃▃▃▁▂▁▂▃▃▃▃▃▅▄▄▄▃▄▂▃▂▁▁▂▂▃▂▂3029.02866.02931.02820.02766.02291.02777.02685.02610.02695.02403.02622.02574.02535.02448.02398.02366.02330.02390.02433.02348.02195.02269.02153.02327.02352.02378.02411.02440.02463.02613.02504.02493.02503.02434.02466.02246.02401.02259.02175.02198.02315.02298.02363.02233.02315.0
  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 █▆▇▆▅▃▅▄▄▃▂▃▃▃▂▂▂▁▁▂▂▁▁▁▁▁▁▂▄▃▂▂▃▃▃▃▂▂▁▂▂66207.063713.064026.062775.062095.058405.060612.060450.059963.058477.057152.057259.057858.057649.056567.056582.056205.055201.055233.056859.056906.055502.055047.054812.055022.055465.055566.055731.059437.058224.057194.057187.057567.058727.058522.058612.056499.056007.055179.055844.055774.0NA55331.0NANANA
us-gaap:Liabilities █▇▇▆▆▄▅▅▄▄▃▃▃▃▂▂▂▂▁▂▃▂▁▁▁▁▁▁▃▃▂▃▃▃▃▃▂▂▂▂▂53539.051624.051319.050754.050450.048043.048397.048327.047876.047022.045935.045749.046443.046224.044323.044413.044177.043508.043264.044664.045020.044032.043291.042547.042788.043028.042772.042697.046363.045642.044543.045034.045623.046322.046208.045952.044285.044026.043622.043888.044025.0NA43807.0NANANA
us-gaap:LiabilitiesAndStockholdersEquity █▆▇▆▅▃▅▄▄▃▂▃▃▃▂▂▂▁▁▂▂▁▁▁▁▁▁▂▄▃▂▂▃▃▃▃▂▂▁▂▂66207.063713.064026.062775.062095.058405.060612.060450.059963.058477.057152.057259.057858.057649.056567.056582.056205.055201.055233.056859.056906.055502.055047.054812.055022.055465.055566.055731.059437.058224.057194.057187.057567.058727.058522.058612.056499.056007.055179.055844.055774.0NA55331.0NANANA
us-gaap:StockholdersEquity ▇▅▇▅▄▁▆▆▅▄▃▄▄▄▆▆▅▄▅▆▅▄▅▆▆▆▇██▇▇▆▅▆▆▇▆▅▄▅▄12668.012089.012707.012021.011645.010362.012215.012123.012087.011455.011217.011510.011415.011425.012244.012169.012028.011693.011969.012195.011886.011470.011756.012265.012234.012437.012794.013034.013074.012582.012651.012153.011944.012405.012314.012660.012214.011981.011557.011808.011602.0NA10954.0NANANA
  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:Cash ▅▆▄▄▆█▃▃▃▂▃▃▃▃▄▃▂▃▃▃▃▃▄▃▂▂▂▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁462.0588.0419.0442.0586.0857.0242.0340.0271.0223.0310.0310.0288.0282.0355.0283.0225.0299.0271.0290.0289.0242.0387.0236.0145.0201.0190.0247.0204.0206.0195.0185.0121.0123.0156.0129.0100.059.075.084.084.081.077.082.072.0NA
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents ▄▅▃▃▅█▁▂▂▁▂▂▂462.0588.0419.0442.0586.0857.0242.0340.0271.0223.0310.0310.0288.0NA355.0NANANA271.0NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:ShortTermInvestments us-gaap:ConsolidatedEntities srt:ParentCompanyNANA522.0NANANA521.0NANANA519.0NANANA638.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  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:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment ▂▂▂▁▁▁▁▁▁▁▁▁▂▂▂▂▂▂▂▂▁▁▄▅▄▄▄▄▄▄▄▄▄▅▅▅▅▅▅██252.0243.0231.0224.0211.0224.0215.0201.0208.0214.0216.0208.0234.0253.0274.0275.0263.0255.0254.0236.0224.0214.0382.0387.0376.0364.0364.0362.0365.0367.0365.0358.0379.0406.0404.0408.0428.0425.0420.0567.0567.0NA543.0NANANA
us-gaap:PropertyPlantAndEquipmentNet ▁▂▂▂▃▃▄▅▅▆▇▇██▇▇▇▇▆▄▄▃█▆▆▅▅▄▄▅▅▇▇▇▇▆▆▆▆▇▅234.0244.0252.0256.0264.0271.0282.0293.0302.0314.0324.0332.0347.0346.0326.0325.0336.0324.0310.0287.0276.0263.0343.0320.0317.0298.0295.0287.0289.0293.0304.0334.0327.0323.0326.0317.0310.0307.0309.0324.0300.0NA333.0NANANA
us-gaap:Goodwill ▃▃▃▂▁▁▂▁▂▂▂▂▂▄▃▂▂▂▁▂▂▄▄▅▆▅▅▇█▇▇▇▅▅▇148.0148.0148.0146.0145.0145.0147.0145.0146.0147.0146.0147.0147.0149.0148.0147.0147.0146.0145.0146.0147.0150.0150.0151.0153.0151.0152.0154.0156.0155.0155.0154.0152.0151.0154.0NANANA123.0NANANANANANANA
us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill NANA64.0NANANA62.0NANANA61.0NANANA63.0NANANA59.0NANANA68.0NANANA71.073.076.074.074.073.069.069.073.0NANANA16.0NANANANANANANA
 us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill us-gaap:IndefiniteLivedIntangibleAssetsByMajorClass cna:LloydsSyndicateCapacityNANA48.0NANANA46.0NANANA45.0NANANA47.0NANANA43.0NANANA52.0NANANA55.057.060.058.058.0NANANA57.0NANANANANANANANANANANA
us-gaap:DeferredTaxAssetsLiabilitiesNet NANA66.0NANANA199.0NANANA392.0NANANA137.0141.0166.0267.0379.0221.0293.0461.0638.0279.0255.057.0191.0NANA48.0220.0331.0315.021.093.08.0127.0201.0378.0205.0376.0NA667.0NANANA
us-gaap:OperatingLeaseRightOfUseAsset NANA199.0NANANA220.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:EquitySecuritiesFvNi █▇▇▅▃▂▃▃▃▂▁▂▁1033.0984.0992.0919.0859.0799.0865.0841.0830.0814.0780.0795.0773.0NA695.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  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:LongTermDebt NANA2776.0NANANA2679.0NANANA2680.0NANANA2858.0NANANA2710.0NANANA2562.0NANANA2559.0NANANA2560.0NANANA2570.0NANANA2608.0NANANA2651.0NANANA
us-gaap:LongTermDebtNoncurrent ████▇▇▇▇▇▇▇▇▇▇▇▇▆▆▇▇▇▇▃▃▆▆▆▆▆▆▁▆▆▆▆▆▆▆▆▆▇2777.02777.02776.02776.02680.02680.02679.02678.02678.02681.02680.02680.02679.02679.02708.02707.02561.02560.02710.02709.02708.02708.02212.02211.02560.02560.02559.02559.02558.02558.02011.02559.02558.02558.02557.02557.02526.02526.02525.02538.02648.0NA2251.0NANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo NANA41.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree NANA36.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour NANA29.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive NANA24.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive NANA163.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  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 ▇▅▇▅▄▁▆▆▅▄▃▄▄▄▆▆▅▄▅▆▅▄▅▆▆▆▇██▇▇▆▅▆▆▇▆▅▄▅▄12668.012089.012707.012021.011645.010362.012215.012123.012087.011455.011217.011510.011415.011425.012244.012169.012028.011693.011969.012195.011886.011470.011756.012265.012234.012437.012794.013034.013074.012582.012651.012153.011944.012405.012314.012660.012214.011981.011557.011808.011602.0NA10954.0NANANA
us-gaap:AdditionalPaidInCapitalCommonStock ▇▆█▇▇▆▇▇▆▅▆▆▅▄▅▄▄▃▄▃▃▂▂▂▂▁▂▂▂▂▂▁▁▁▂▂▁▁▂▂▁2201.02194.02211.02202.02196.02187.02203.02197.02190.02184.02192.02186.02179.02173.02175.02167.02167.02161.02173.02163.02155.02146.02153.02150.02146.02143.02151.02149.02146.02144.02145.02142.02140.02138.02146.02144.02141.02140.02146.02144.02143.0NA2200.0NANANA
us-gaap:RetainedEarningsAccumulatedDeficit ▇▅▅▄▃▃▇▆▆▅▆▇▆▅▇▆▆▅▇▆▅▄▆▇▇▆█▇▇▆▇▆▅▅▄▄▃▃▂▁▁9348.09084.09081.08796.08683.08634.09348.09171.09159.08976.09277.09456.09216.09028.09414.09273.09211.09006.09359.09185.08911.08770.09313.09450.09340.09270.09645.09515.09369.09170.09495.09328.09110.08969.08774.08823.08643.08517.08382.08219.08171.0NA7876.0NANANA
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax ▆▅▇▆▅▁▅▅▅▃▂▂▂▃▅▅▅▄▄▅▅▄▃▅▅▆▆▇▇▇▆▅▅▇▇█▇▇▆▇▇509.0187.0803.0411.0154.0-1070.051.0139.0120.0-324.0-878.0-757.0-605.0-400.032.0107.032.0-92.0-173.0237.0210.0-56.0-315.060.0143.0421.0400.0773.0962.0692.0442.0113.0126.0727.0831.01130.0867.0764.0470.0886.0730.0NA326.0NANANA
us-gaap:TreasuryStockValue ▃▁▃▃▃▃▃▃▂▂▁▁▁▁▁▂▂▂▃▃▃▃▄▄▄▄▅▅▅▅▆▆▆▆███████73.059.071.071.071.072.070.067.065.064.057.058.058.059.060.061.065.065.073.073.073.073.078.078.078.079.084.085.085.085.091.091.091.092.099.099.099.0100.0102.0102.0102.0NA105.0NANANA
 us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapital▇▁█▇█▁▇▇▇▃▇▇▇▅█▆▇▂7.0-17.09.06.09.0-16.06.07.06.0-8.06.07.06.0-2.08.00.06.0-12.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap:StatementEquityComponents us-gaap:TreasuryStock▁█▁▁▁█▂▁▁▄▁▁▁▁▁▃▁▄1.015.00.00.01.016.02.00.01.07.01.00.01.01.01.04.00.08.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  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 ▇▅▆█▇▆▆▇▆▆▆▇▆▆▆▆▆▆▆▇▆▆▆▇▇▅▆▇▆▆▆▆▆▆▆▆▆▆█▆▆▅▇▁603.082.0367.0758.0438.0212.0160.0466.0227.0287.0359.0514.0136.0218.0360.0379.0233.0282.0296.0507.0279.0334.0342.0505.0446.094.0393.0460.0419.0168.0283.0352.0378.0191.0257.0375.0306.0312.0889.0401.0300.0112.0584.0-1254.0NANA
us-gaap:NetCashProvidedByUsedInInvestingActivities ▂▅▃▁▂▇▃▃▄▅▃▃▄▅▃▃▃▅▃▂▃▄▃▃▂▅▄▃▃▃▃▃▃▃▃▃▃▃▁▃▄▃▃█-610.0408.0-298.0-882.0-612.01087.0-165.0-293.0-56.0289.0-257.0-359.0-50.0489.0-206.0-329.0-243.0354.0-242.0-437.0-158.0-9.0-118.0-341.0-439.0526.0169.0-353.0-380.0-354.0-209.0-218.0-310.0-161.0-187.0-237.0-223.0-287.0-843.0-314.0171.0-74.0-93.01383.0NANA
us-gaap:NetCashProvidedByUsedInFinancingActivities ▆▄▆▆▆▂▆▆▆▂▆▆▆▁▆▇▆▂▆▆▆▃▆▆▆▂▂▆▆█▆▆▆▆▆▆▆▆▆▆▃▆▃▆-120.0-321.0-101.0-25.0-101.0-675.0-101.0-99.0-123.0-665.0-96.0-134.0-74.0-781.0-82.04.0-68.0-609.0-68.0-67.0-69.0-469.0-68.0-69.0-67.0-603.0-614.0-68.0-47.0210.0-64.0-73.0-71.0-56.0-44.0-112.0-41.0-42.0-56.0-84.0-468.0-36.0-497.0-121.0NANA
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect ▂▄▃▂▁█▂▄▄▂▃-126.0169.0-23.0-144.0-271.0615.0-98.069.048.0-87.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  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:DeferredIncomeTaxExpenseBenefit ▆█▆▆▆▄█▁▆█-3.030.0-8.0-8.04.0-37.026.0-97.0-7.032.0NANANANANANANANA24.049.08.055.0-177.0-5.0-39.071.0-80.033.023.025.0-64.019.023.099.052.014.08.073.039.055.09.089.0164.081.0NANA
us-gaap:DepreciationDepletionAndAmortization ▁▁▁▁▁▂▂▂▂▂▃▂▃▃▃▃▃▃▃▂▂▃▃▃▃▂▃▃▃▃▃▃▄▆██▂▃▃13.014.014.015.015.016.016.016.017.019.020.018.021.020.022.023.022.021.020.018.018.021.022.023.020.019.021.020.022.020.021.022.025.033.042.044.019.020.020.0NANANANANANANA
us-gaap:NetCashProvidedByUsedInOperatingActivities ▇▅▆█▇▆▆▇▆▆▆▇▆▆▆▆▆▆▆▇▆▆▆▇▇▅▆▇▆▆▆▆▆▆▆▆▆▆█▆▆▅▇▁603.082.0367.0758.0438.0212.0160.0466.0227.0287.0359.0514.0136.0218.0360.0379.0233.0282.0296.0507.0279.0334.0342.0505.0446.094.0393.0460.0419.0168.0283.0352.0378.0191.0257.0375.0306.0312.0889.0401.0300.0112.0584.0-1254.0NANA
us-gaap:NetIncomeLoss █▇█▆▅▂▆▄▇▇▂▇▆▇▆▅▆▆▆▇▆▄▂▅▅▆▅▆▆▃▆▆▅▆▃▆▅▆▅▄▅▆▇▁▇▆368.0312.0387.0213.0151.0-61.0273.0107.0278.0342.0-84.0336.0270.0291.0223.0144.0272.0260.0241.0343.0209.066.0-70.0178.0138.0233.0198.0213.0267.013.0221.0272.0194.0250.0-9.0221.0166.0250.0190.075.0126.0223.0302.0-140.0283.0245.0
  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 ▂▅▃▁▂▇▃▃▄▅▃▃▄▅▃▃▃▅▃▂▃▄▃▃▂▅▄▃▃▃▃▃▃▃▃▃▃▃▁▃▄▃▃█-610.0408.0-298.0-882.0-612.01087.0-165.0-293.0-56.0289.0-257.0-359.0-50.0489.0-206.0-329.0-243.0354.0-242.0-437.0-158.0-9.0-118.0-341.0-439.0526.0169.0-353.0-380.0-354.0-209.0-218.0-310.0-161.0-187.0-237.0-223.0-287.0-843.0-314.0171.0-74.0-93.01383.0NANA
us-gaap:PaymentsToAcquirePropertyPlantAndEquipment ▁▁▂▂▂▁▂▂▂▂▂▂▆▆▄▂▆▅█▅▅▅▆▄▆▄▅▃▃▂▄▄▄▄▅▃▄▄▃▇▃▂▃▃2.03.07.06.07.03.06.06.06.08.012.011.038.038.022.012.038.030.052.029.032.033.041.027.037.020.029.015.017.010.024.025.021.021.034.018.020.022.017.043.013.011.015.015.0NANA
  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 ▆▄▆▆▆▂▆▆▆▂▆▆▆▁▆▇▆▂▆▆▆▃▆▆▆▂▂▆▆█▆▆▆▆▆▆▆▆▆▆▃▆▃▆-120.0-321.0-101.0-25.0-101.0-675.0-101.0-99.0-123.0-665.0-96.0-134.0-74.0-781.0-82.04.0-68.0-609.0-68.0-67.0-69.0-469.0-68.0-69.0-67.0-603.0-614.0-68.0-47.0210.0-64.0-73.0-71.0-56.0-44.0-112.0-41.0-42.0-56.0-84.0-468.0-36.0-497.0-121.0NANA
us-gaap:ProceedsFromIssuanceOfLongTermDebt NANA0.0495.0NANA0.00.0NANA0.00.0NANA0.0496.00.00.00.00.00.0498.00.00.00.00.00.00.00.0546.0NANANANANANANANA0.00.00.0396.00.0495.0NANA
us-gaap:RepaymentsOfLongTermDebt NANA0.0419.0NANA0.00.0520.00.00.030.00.0150.00.0391.00.00.00.00.00.0358.00.00.00.00.0NANANANA0.0NANANA0.0NANANA31.011.00.0409.00.0100.0NANA
us-gaap:PaymentsOfDividendsCommonStock ▂▄▂▂▂█▂▂▂█▂▂▂█▂▂▁█▁▁▁█▁▁▁█▁▁▁▄▁▁▁▁▁▁▁▁▁▁▁▁104.0310.0100.0100.0101.0649.095.096.095.0643.095.095.082.0624.081.085.067.0609.067.069.068.0609.067.068.068.0608.068.067.068.0338.054.054.053.055.040.041.040.041.027.027.027.027.0NANANANA
us-gaap:PaymentsForRepurchaseOfCommonStock ▇▂▁▁▁█▃▂▂▆▁▁▁▁15.03.00.00.00.018.05.02.02.014.00.00.00.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  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

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value2722722722722712722722722722722722722712712712702702702700.0270270270270270269269269269269269269269269
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value2712712712712712712712712712712712712712702702702702702700.0269269269269269269269269269269269269269269
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount


Antidilutive
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-31
Value1000.0120000.09000.0915000.01015000.01000.01000.001000.0445000.09000.01000.01000.0148000.0175000.0178000.0180000.0106000.0238000.0182000.0180000.0180000.0110000.0110000.0114000.0335000.0693000.0622000.0668000.01200000.0931000.01000000.0
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareBasic


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-312011-09-302011-06-30
Value1.351.151.420.790.56-0.231.00.391.031.26-0.311.240.991.070.820.531.010.960.891.270.770.25-0.260.660.510.860.730.790.990.050.821.010.720.93-0.040.820.620.710.280.46
Percentage of EarningsPerShareBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareDiluted


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-312011-09-302011-06-30
Value1.351.141.420.790.55-0.231.00.391.021.25-0.311.230.991.070.820.531.00.960.891.260.770.24-0.260.660.510.860.730.790.980.050.821.010.720.93-0.030.820.620.710.280.46
Percentage of EarningsPerShareDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Benefits Losses And Expenses

us-gaap:BenefitsLossesAndExpenses

us-gaap:BenefitsLossesAndExpenses


Benefits
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
Value256724882453257025842380244225582268227625172220224421892038221119961987207319582060213824301920216320392126211820762165231421292217214024702152201620372020205120191984182225301787
Percentage of BenefitsLossesAndExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax715.0736.183.7810.7839.0790.787.9876.0795.8810.0104.7860.587.286.483.392.284.485.386.780.587.797.4107.189.293.086.789.487.885.187.988.685.088.985.5101.587.389.884.889.494.391.985.779.3107.180.0

us-gaap:BenefitsLossesAndExpenses us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Benefits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-1.0-2.0-2.0-1.0-1.0-2.0-1.0-2.0-1.0-3.0-1.0-1.00.0-1.00.00.0-1.00.00.00.0-1.00.0
Percentage of BenefitsLossesAndExpenses-0.0-0.1-0.1-0.0-0.0-0.1-0.0-0.1-0.0-0.1-0.0-0.00.0-0.00.00.0-0.10.00.00.0-0.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.3-0.6-0.1-0.3-0.3-0.7-0.0-0.7-0.4-1.1-0.0-0.40.0-0.00.00.0-0.00.00.00.0-0.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:BenefitsLossesAndExpenses us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Benefits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value889921828962902837836835
Percentage of BenefitsLossesAndExpenses34.637.033.837.434.935.234.232.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax247.6272.528.2303.5292.9278.130.1286.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:InternationalSegment


Benefits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value245237223225255252238261
Percentage of BenefitsLossesAndExpenses9.59.59.18.89.910.69.710.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax68.270.17.671.082.883.78.689.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Benefits
Period End2021-06-302021-03-312020-06-302020-03-31
Value349308329345
Percentage of BenefitsLossesAndExpenses13.612.412.714.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax97.291.1106.8114.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeAndGroupNonCoreSegment0.00.00.00.0

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Benefits
Period End2020-09-302019-09-30
Value394506
Percentage of BenefitsLossesAndExpenses15.319.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax124.3173.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeandGroupSegment0.00.0

us-gaap:OperatingSegments, cna:SpecialtySegment


Benefits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value10149749919641030920921930
Percentage of BenefitsLossesAndExpenses39.539.140.437.539.938.737.736.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax282.5288.233.8304.1334.4305.633.2318.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SpecialtySegment282.5288.20.0304.1334.4305.60.0318.5

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Benefits
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value715079261625942821177631538323374765404339182
Percentage of BenefitsLossesAndExpenses2.82.03.21.00.61.13.81.10.90.73.01.42.43.81.11.72.43.31.92.21.98.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax19.814.82.78.25.28.33.49.67.46.03.212.02.13.30.91.52.02.81.71.81.78.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments us-gaap:CorporateAndOther0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:ComprehensiveIncomeNetOfTax


Comprehensive
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
Value690-304.07794701375-1182.0185126722896-205.018465-125.0148219396341-169.0370475325-445.095-140.0254-175.024537263550259-407.0146-308.0484269534-218.0231422309-549.0645684
Percentage of ComprehensiveIncomeNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax192.2-89.926.6148.3446.4-392.76.743.2253.3318.9-8.571.32.5-4.96.09.116.714.6-7.115.220.214.8-19.64.4-6.010.8-7.41.022.010.721.010.3-16.35.8-12.719.612.022.2-9.710.619.213.3-23.927.330.6

Deferred Policy Acquisition Cost Amortization Expense

us-gaap:DeferredPolicyAcquisitionCostAmortizationExpense

us-gaap:DeferredPolicyAcquisitionCostAmortizationExpense


Deferred
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
Value357359364360342344358345338342343337359296307309312305309314305307604319314303321332335329358341335328337333309295359356350297349351345
Percentage of DeferredPolicyAcquisitionCostAmortizationExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax99.4106.212.4113.6111.0114.312.9118.2118.6121.714.3130.613.911.712.512.913.213.112.912.913.014.026.614.813.512.913.513.813.713.413.713.613.413.113.813.513.812.315.916.415.912.815.214.915.5

us-gaap:DeferredPolicyAcquisitionCostAmortizationExpense us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value148153151150147144146134
Percentage of DeferredPolicyAcquisitionCostAmortizationExpense41.542.641.541.743.041.940.838.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax41.245.35.247.347.747.85.345.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:InternationalSegment


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value5052545242495656
Percentage of DeferredPolicyAcquisitionCostAmortizationExpense14.014.514.814.412.314.215.616.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax13.915.41.816.413.616.32.019.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:SpecialtySegment


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value159154159158153151156155
Percentage of DeferredPolicyAcquisitionCostAmortizationExpense44.542.943.743.944.743.943.644.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax44.345.65.449.849.750.25.653.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SpecialtySegment44.345.60.049.849.750.20.053.1

Income Loss From Continuing Operations

us-gaap:IncomeLossFromContinuingOperations

us-gaap:IncomeLossFromContinuingOperations


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
Value368312387213151-61.0273107278342-84.033627029122314427226024134320966-70.0178138233198209261220235271190241-9.022116625019075126221302-118.0282
Percentage of IncomeLossFromContinuingOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax102.592.313.267.249.0-20.39.836.697.5121.7-3.5130.210.511.59.16.011.511.210.114.18.93.0-3.18.35.99.98.38.710.78.99.010.87.69.6-0.49.07.410.48.43.45.79.513.1-5.012.6

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
Value462378478250182-89.0335127342419-114.040233034641018737034331747528857-161.0233164313252293364298299375276363-36.0314230364239124176331476-167.0
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 RevenueFromContractWithCustomerExcludingAssessedTax128.7111.816.378.959.1-29.612.143.5120.0149.1-4.7155.812.813.616.77.815.614.713.319.512.32.6-7.110.87.013.310.612.214.912.111.415.011.114.5-1.512.710.215.210.65.78.014.320.7-7.1

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxExpenseBenefit


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value9466913731-28.062206477-30.06660551874398837613279-9.0-91.05526805484103787810382113-27.09364114484947101150-64.0145
Percentage of IncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax26.219.53.111.710.1-9.32.26.822.527.4-1.225.62.32.27.61.84.13.63.25.43.4-0.4-4.02.61.13.42.33.54.23.23.04.13.34.5-1.13.82.84.72.12.32.14.46.5-2.76.5

Interest Expense

us-gaap:InterestExpense

us-gaap:InterestExpense


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value292828323131313234343434353537414043403938423839393945484644414241424243434243434346444037
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax8.18.31.010.110.110.31.111.011.912.11.413.21.41.41.51.71.71.81.71.61.61.91.71.81.71.71.92.01.91.81.61.71.61.71.71.71.91.71.92.02.02.01.91.71.7

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
Value368312387213151-61.0273107278342-84.033627029122314427226024134320966-70.017813823319821326713221272194250-9.022116625019075126223302-140.0283245
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 RevenueFromContractWithCustomerExcludingAssessedTax102.592.313.267.249.0-20.39.836.697.5121.7-3.5130.210.511.59.16.011.511.210.114.18.93.0-3.18.35.99.98.38.810.90.58.510.97.810.0-0.49.07.410.48.43.45.79.613.1-5.912.710.6

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value368312387213151-61.0273107278342-84.03362702912231442722602413432096623319821326713221272194250-9.0221166250
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax102.592.313.267.249.0-20.39.836.697.5121.7-3.5130.210.511.59.16.011.511.210.114.18.93.09.98.38.810.90.58.510.97.810.0-0.49.07.410.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Net Investment Income

us-gaap:NetInvestmentIncome

us-gaap:NetInvestmentIncome


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
Value591504555517534329545487515571334487506490
Percentage of NetInvestmentIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax164.6149.118.9163.1173.4109.319.6166.8180.7203.213.9188.819.719.3

Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax

us-gaap:OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax

us-gaap:OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value122.0633724-77.051-29.00.017-42.00.0-52.0126.0414211-56.0-24.0-48.014-39.0-53.049-96.0-56.0-73.042-8.07.056-13.0-61.03.033-17.021
Percentage of OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax3.30.62.111.77.8-25.61.8-9.90.06.0-1.70.0-2.00.50.21.71.80.5-2.3-1.0-2.00.6-1.7-2.52.1-4.1-2.4-3.01.7-0.30.32.2-0.5-2.40.11.3-0.80.9

Other Comprehensive Income Loss Net Of Tax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value322-616.03922571224-1121.0-88.019444554-121.0-152.0-205.0-416.0-75.07512481-410.027266259-375.0-83.0-278.021-373.0-189.0270250329-13.0-601.0-104.0
Percentage of OtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.7-182.213.481.1397.4-372.4-3.26.5155.8197.2-5.0-58.9-8.0-16.4-3.13.15.23.5-17.21.111.311.8-16.5-3.9-11.90.9-15.7-7.811.110.212.6-0.5-24.1-4.2

us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-03-31
Value322-616.03922571224-1121.0-88.019444554-121.0-152.0-205.0-416.0-75.07512481-410.02726625921-373.0-189.0270250329-13.0-601.0-104.0284
Percentage of OtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.7-182.213.481.1397.4-372.4-3.26.5155.8197.2-5.0-58.9-8.0-16.4-3.13.15.23.5-17.21.111.311.80.9-15.7-7.811.110.212.6-0.5-24.1-4.211.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Other Income

us-gaap:OtherIncome

us-gaap:OtherIncome


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value6.05.07.06.05.08.09.09.04.09.02410.06.010.01091071071041119610097121979297948493857678129789076866880767167667575
Percentage of OtherIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.71.50.21.91.62.70.33.11.43.21.03.90.20.44.54.54.54.54.63.94.34.45.34.54.04.14.03.53.83.52.93.15.23.13.73.13.82.83.53.53.22.92.93.23.4

us-gaap:OtherIncome us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-1.0-2.0-2.00.0-1.0-2.0-1.0-1.0-1.0-2.0-1.00.00.0-1.00.00.00.00.00.00.00.00.0
Percentage of OtherIncome-16.7-40.0-28.60.0-20.0-25.0-11.1-11.1-25.0-22.2-4.20.00.0-10.00.00.00.00.00.00.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.3-0.6-0.10.0-0.3-0.7-0.0-0.3-0.4-0.7-0.00.00.0-0.00.00.00.00.00.00.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherIncome us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value5.05.07.06.05.08.09.010.0
Percentage of OtherIncome83.3100.0100.0100.0100.0100.0100.0111.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.41.50.21.91.62.70.33.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:InternationalSegment


Other
Period End2021-06-302019-09-30
Value1.0-1.0
Percentage of OtherIncome16.7-11.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.3-0.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:InternationalSegment0.00.0

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Other
Period End2021-06-302021-03-31
Value-1.01.0
Percentage of OtherIncome-16.720.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.30.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeAndGroupNonCoreSegment0.00.0

us-gaap:OperatingSegments, cna:SpecialtySegment


Other
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value0.00.00.01.00.01.0
Percentage of OtherIncome0.00.00.012.50.011.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.00.00.30.00.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SpecialtySegment0.00.00.00.30.00.3

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value2.01.02.00.01.02.01.01.02.02.0172.0-1.01.01.00.01.00.09.00.00.03.0
Percentage of OtherIncome33.320.028.60.020.025.011.111.150.022.270.820.0-16.710.00.90.00.90.08.10.00.03.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.60.30.10.00.30.70.00.30.70.70.70.8-0.00.00.00.00.00.00.40.00.00.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments us-gaap:CorporateAndOther0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Policyholder Benefits And Claims Incurred Net

us-gaap:PolicyholderBenefitsAndClaimsIncurredNet

us-gaap:PolicyholderBenefitsAndClaimsIncurredNet


Policyholder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-06-30
Value1539150014831611163614191479160713461351158713061321133312491475127512891336119513351404137311981466133513461351143714431579140815151425171714301342137813511399136713631147
Percentage of PolicyholderBenefitsAndClaimsIncurredNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax428.7443.850.6508.2531.2471.453.3550.3472.3480.866.0506.251.352.651.061.553.955.355.949.156.964.060.555.663.056.856.656.058.958.660.456.260.856.970.558.059.857.459.864.362.258.951.4

us-gaap:PolicyholderBenefitsAndClaimsIncurredNet us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Policyholder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value588639539673614555549564
Percentage of PolicyholderBenefitsAndClaimsIncurredNet38.242.636.341.837.539.137.135.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax163.8189.118.4212.3199.4184.419.8193.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:InternationalSegment


Policyholder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value159155149150176154152163
Percentage of PolicyholderBenefitsAndClaimsIncurredNet10.310.310.09.310.810.910.310.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax44.345.95.147.357.151.25.555.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Policyholder
Period End2021-06-302021-03-312020-06-302020-03-31
Value322281304316
Percentage of PolicyholderBenefitsAndClaimsIncurredNet20.918.718.622.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.783.198.7105.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeAndGroupNonCoreSegment0.00.00.00.0

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Policyholder
Period End2020-09-302019-09-30
Value363476
Percentage of PolicyholderBenefitsAndClaimsIncurredNet22.529.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax114.5163.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeandGroupSegment0.00.0

us-gaap:OperatingSegments, cna:SpecialtySegment


Policyholder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value439427446433508405397411
Percentage of PolicyholderBenefitsAndClaimsIncurredNet28.528.530.126.931.128.526.825.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax122.3126.315.2136.6164.9134.614.3140.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SpecialtySegment122.3126.30.0136.6164.9134.60.0140.8

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Policyholder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value31-2.046-8.0-18.0-14.058-7.0-12.0-21.036-12.0-14.041-23.0-15.0-2.021-11.0-11.0-8.0128
Percentage of PolicyholderBenefitsAndClaimsIncurredNet2.0-0.13.1-0.5-1.1-1.03.9-0.4-0.9-1.62.3-0.9-1.13.1-1.8-1.0-0.21.6-0.8-0.9-0.69.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax8.6-0.61.6-2.5-5.8-4.72.1-2.4-4.2-7.51.5-4.7-0.51.6-0.9-0.6-0.10.9-0.5-0.5-0.35.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments us-gaap:CorporateAndOther0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Premiums Earned Net

us-gaap:PremiumsEarnedNet

us-gaap:PremiumsEarnedNet


Premiums
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
Value203519621977195318501869191118901824180318591853181517851803180617341645172817671730169917481751173516871785181018111806188218251800176417841781166816491661173215951615164716451608
Percentage of PremiumsEarnedNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax566.9580.567.5616.1600.6620.968.8647.3640.0641.677.4718.270.570.473.775.373.370.672.372.673.777.477.081.374.671.775.175.174.273.372.072.972.270.573.372.274.368.773.579.672.669.871.769.672.0

us-gaap:PremiumsEarnedNet us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Premiums
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value0.0-1.00.00.00.0-1.00.0-1.00.0-1.00.00.00.00.0-1.00.00.00.0-1.00.0
Percentage of PremiumsEarnedNet0.0-0.10.00.00.0-0.10.0-0.10.0-0.10.00.00.00.0-0.10.00.00.0-0.10.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.0-0.30.00.00.0-0.30.0-0.40.0-0.40.00.00.00.0-0.00.00.00.0-0.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:PremiumsEarnedNet us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Premiums
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value881855853857795818823813
Percentage of PremiumsEarnedNet43.343.643.143.943.043.843.143.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax245.4253.029.1270.3258.1271.829.6278.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:InternationalSegment


Premiums
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value266252241236224239245236
Percentage of PremiumsEarnedNet13.112.812.212.112.112.812.812.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax74.174.68.274.472.779.48.880.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Premiums
Period End2021-06-302021-03-312020-06-302020-03-31
Value126120126127
Percentage of PremiumsEarnedNet6.26.16.86.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax35.135.540.942.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeAndGroupNonCoreSegment0.00.00.00.0

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Premiums
Period End2020-09-302019-09-30
Value127130
Percentage of PremiumsEarnedNet6.56.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax40.144.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeandGroupSegment0.00.0

us-gaap:OperatingSegments, cna:SpecialtySegment


Premiums
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value762735759734705685712712
Percentage of PremiumsEarnedNet37.437.538.437.638.136.737.337.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax212.3217.525.9231.5228.9227.625.6243.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SpecialtySegment212.3217.50.0231.5228.9227.60.0243.8

Realized Investment Gains Losses

us-gaap:RealizedInvestmentGainsLosses us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:RealizedInvestmentGainsLosses

cna:SeniorNotes5750FaceAmount400DueAugust152021, us-gaap:SeniorNotes


Realized
Period End2020-12-312020-09-30
Value-40.020
Percentage of RealizedInvestmentGainsLosses100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-1.46.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax cna:SeniorNotes5750FaceAmount400DueAugust152021 us-gaap:SeniorNotes0.00.0

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
Value3593382931317308301277729228528124032582574253524482398236623302390243323482195226921532327235223782411244024632613250424932503243424662246240122592175219823152298236322332315
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 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

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:SpecialtySegment


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value359338326317308301303292
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.011.1100.0100.0100.010.9100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.011.1100.0100.0100.010.9100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SpecialtySegment100.0100.0100.0100.0100.0100.0100.0100.0

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
Value3029286629312820276622912777268526102695240326222574253524482398236623302390243323482195226921532327235223782411244024632613250424932503243424662246240122592175219823152298236322332315
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 RevenueFromContractWithCustomerExcludingAssessedTax843.7847.9100.0889.6898.1761.1100.0919.5915.8959.1100.01016.3100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Revenues us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-1.0-2.0-2.0-1.0-1.0-2.0-1.0-2.0-1.0-3.0-1.0-1.00.0-1.00.00.0-1.00.00.00.0-1.00.0
Percentage of Revenues-0.0-0.1-0.1-0.0-0.0-0.1-0.0-0.1-0.0-0.1-0.0-0.00.0-0.00.00.0-0.00.00.00.0-0.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.3-0.6-0.1-0.3-0.3-0.7-0.0-0.7-0.4-1.1-0.0-0.40.0-0.00.00.0-0.00.00.00.0-0.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:Revenues us-gaap:ConsolidationItems, us-gaap:ProductOrService, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CNACanada, cna:InternationalSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value8779777368737370
Percentage of Revenues2.92.82.62.62.53.22.62.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax24.223.42.623.022.124.32.624.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CNACanada cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:CNAEurope, cna:InternationalSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1151111079694929391
Percentage of Revenues3.83.93.73.43.44.03.33.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax32.032.83.730.330.530.63.331.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CNAEurope cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:Hardy, cna:InternationalSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value7976718276899591
Percentage of Revenues2.62.72.42.92.73.93.43.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax22.022.52.425.924.729.63.431.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:Hardy cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:ManagementandProfessionalLiability, cna:SpecialtySegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value693667696668645568669638
Percentage of Revenues22.923.323.723.723.324.824.123.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax193.0197.323.7210.7209.4188.724.1218.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:ManagementandProfessionalLiability cna:SpecialtySegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:MiddleMarkets, cna:CommercialSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value381375376381355335374357
Percentage of Revenues12.613.112.813.512.814.613.513.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax106.1110.912.8120.2115.3111.313.5122.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:MiddleMarkets cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:OtherCommercialInsurance, cna:CommercialSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value212198233223217171216213
Percentage of Revenues7.06.97.97.97.87.57.87.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax59.158.67.970.370.556.87.872.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:OtherCommercialInsurance cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:SmallBusiness, cna:CommercialSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value143126130126114112127124
Percentage of Revenues4.74.44.44.54.14.94.64.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax39.837.34.439.737.037.24.642.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SmallBusiness cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:Surety, cna:SpecialtySegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value155142152153153138150156
Percentage of Revenues5.15.05.25.45.56.05.45.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax43.242.05.248.349.745.85.453.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:Surety cna:SpecialtySegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:WarrantyAlternativeRisks, cna:SpecialtySegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value407381371356348337342332
Percentage of Revenues13.413.312.712.612.614.712.312.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax113.4112.712.7112.3113.0112.012.3113.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:WarrantyAlternativeRisks cna:SpecialtySegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, us-gaap:Construction, cna:CommercialSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value324309297298275250289265
Percentage of Revenues10.710.810.110.69.910.910.49.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax90.391.410.194.089.383.110.490.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments us-gaap:Construction cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:Revenues us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value10601008103610289618681006959
Percentage of Revenues35.035.235.336.534.737.936.235.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax295.3298.235.3324.3312.0288.436.2328.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:CommercialSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:InternationalSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value281266255251238254261252
Percentage of Revenues9.39.38.78.98.611.19.49.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax78.378.78.779.277.384.49.486.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:InternationalSegment0.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-06-302020-03-31
Value390340332335
Percentage of Revenues12.911.912.014.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax108.6100.6107.8111.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeAndGroupNonCoreSegment0.00.00.00.0

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Revenuesus-gaap:
Period End2020-09-302019-09-30
Value335336
Percentage of Revenues11.912.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax105.7115.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:LifeandGroupSegment0.00.0

us-gaap:OperatingSegments, cna:SpecialtySegment


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value12551190121911771146104311611126
Percentage of Revenues41.441.541.641.741.445.541.841.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax349.6352.141.6371.3372.1346.541.8385.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments cna:SpecialtySegment349.6352.1373.9371.3372.1346.5383.2385.6

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Revenuesus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value6.07.04.03.05.05.07.07.09.09.0217.05.06.042-35.08.07.0186.06.0-2.0
Percentage of Revenues0.20.20.10.10.20.20.30.30.30.30.90.30.20.21.7-1.50.30.30.80.20.3-0.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.72.10.10.91.61.70.32.43.23.20.92.70.20.21.7-1.50.30.30.80.20.3-0.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments us-gaap:CorporateAndOther0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets

us-gaap:Assets

us-gaap:Assets


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value662076371364026627756209558405606126045059963584775715257259578585764956567565825620555201552335685956906555025504754812550225546555566557315943758224571945718757567587275852258612564995600755179558445577455331
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets us-gaap:ConsolidatedEntities

srt:ParentCompany


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value15523149371394915125
Percentage of Assets24.224.624.426.7
Percentage of Assets24.224.624.426.7
Percentage of Assets srt:ParentCompany100.0100.0100.0100.0

Liabilities

us-gaap:Liabilities

us-gaap:Liabilities


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
Value535395162451319507545045048043483974832747876470224593545749464434622444323444134417743508432644466445020440324329142547427884302842772426974636345642445434503445623463224620845952442854402643622438884402543807
Percentage of Liabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets80.981.080.280.981.282.379.879.979.880.480.479.980.380.278.478.578.678.878.378.679.179.378.677.677.877.677.076.678.078.477.978.779.378.979.078.478.478.679.178.678.979.2

us-gaap:Liabilities us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilitiesus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value2816272227322881
Percentage of Liabilities5.55.65.96.5
Percentage of Assets4.44.54.85.1
Percentage of Assets srt:ParentCompany18.118.219.619.0

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:LiabilitiesAndStockholdersEquity


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value662076371364026627756209558405606126045059963584775715257259578585764956567565825620555201552335685956906555025504754812550225546555566557315943758224571945718757567587275852258612564995600755179558445577455331
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilitiesAndStockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Liabilities
Period End2020-12-312019-12-312018-12-312017-12-31
Value15523149371394915125
Percentage of LiabilitiesAndStockholdersEquity24.224.624.426.7
Percentage of Assets24.224.624.426.7
Percentage of Assets srt:ParentCompany100.0100.0100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value126681208912707120211164510362122151212312087114551121711510114151142512244121691202811693119691219511886114701175612265122341243712794130341307412582126511215311944124051231412660122141198111557118081160210954
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets19.119.019.819.118.817.720.220.120.219.619.620.119.719.821.621.521.421.221.721.420.920.721.422.422.222.423.023.422.021.622.121.320.721.121.021.621.621.420.921.120.819.8

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value12707122151121712244
Percentage of StockholdersEquity100.0100.0100.0100.0
Percentage of Assets19.820.219.621.6
Percentage of Assets srt:ParentCompany81.981.880.481.0

us-gaap:StockholdersEquity us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents

srt:CumulativeEffectPeriodOfAdoptionAdjustedBalance, us-gaap:RetainedEarnings


Stockholders
Period End2021-03-312020-12-312020-06-302020-03-312019-12-312019-06-302019-03-312018-12-312017-12-31
Value908490818683863493439159897692779364
Percentage of StockholdersEquity75.171.574.683.376.575.878.482.776.5
Percentage of Assets14.314.214.014.815.415.315.316.216.6
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustedBalance us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.0

srt:CumulativeEffectPeriodOfAdoptionAdjustment, us-gaap:RetainedEarnings


Stockholders
Period End2020-12-312019-12-312017-12-31
Value-5.0-5.0-50.0
Percentage of StockholdersEquity-0.0-0.0-0.4
Percentage of Assets-0.0-0.0-0.1
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustment us-gaap:RetainedEarnings0.00.00.0

us-gaap:StockholdersEquity us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents

us-gaap:OtherInvestments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2021-06-302021-03-312020-12-312020-06-302020-03-312019-12-31
Value1418111817451172-19.01025
Percentage of StockholdersEquity11.29.213.710.1-0.28.4
Percentage of Assets2.11.82.71.9-0.01.7
Percentage of Assets us-gaap:OtherInvestments us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.0

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value-829.0-839.0-848.0-808.0-815.0-822.0-833.0-753.0-760.0-768.0-775.0-751.0-758.0-765.0-645.0-625.0-635.0-640.0-647.0-631.0-637.0-642.0-648.0
Percentage of StockholdersEquity-6.5-6.9-6.7-6.7-7.0-7.9-6.8-6.2-6.3-6.7-6.9-6.5-6.6-6.7-5.3-5.1-5.3-5.5-5.4-5.2-5.4-5.6-5.5
Percentage of Assets-1.3-1.3-1.3-1.3-1.3-1.4-1.4-1.2-1.3-1.3-1.4-1.3-1.3-1.3-1.1-1.1-1.1-1.2-1.2-1.1-1.1-1.2-1.2
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value13791172-19.010101064102358761113271430750809786709642976934624390
Percentage of StockholdersEquity11.510.1-0.28.38.88.55.10.51.02.43.86.16.66.56.15.48.07.95.43.3
Percentage of Assets2.21.9-0.01.71.81.71.00.10.20.50.71.31.41.41.31.21.71.61.10.7
Percentage of Assets us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value509187803411154-1070.051139120-324.0-878.0-757.0-605.0-400.03210732-92.0-173.0237210-56.0-315.04214007739626924421131267278311130867764480
Percentage of StockholdersEquity4.01.56.33.41.3-10.30.41.11.0-2.8-7.8-6.6-5.3-3.50.30.90.3-0.8-1.41.91.8-0.5-2.73.43.15.97.45.53.50.91.15.96.78.97.16.44.2
Percentage of Assets0.80.31.30.70.2-1.80.10.20.2-0.6-1.5-1.3-1.0-0.70.10.20.1-0.2-0.30.40.4-0.1-0.60.80.71.41.61.20.80.20.21.21.41.91.51.40.9
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherThanTemporaryImpairment


Stockholders
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value-3.0-9.0-11.01520202016192021252726263034313227
Percentage of StockholdersEquity-0.0-0.1-0.10.10.20.20.20.10.20.20.20.20.20.20.20.30.30.30.30.2
Percentage of Assets-0.0-0.0-0.00.00.00.00.00.00.00.00.00.00.00.00.00.10.10.10.10.0
Percentage of Assets us-gaap:AccumulatedOtherThanTemporaryImpairment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedTranslationAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value-80.0-92.0-94.0-157.0-194.0-218.0-141.0-192.0-163.0-163.0-180.0-138.0-138.0-86.0-98.0-104.0-145.0-187.0-198.0-142.0-118.0-70.0-84.0
Percentage of StockholdersEquity-0.6-0.8-0.7-1.3-1.7-2.1-1.2-1.6-1.3-1.4-1.6-1.2-1.2-0.8-0.8-0.9-1.2-1.6-1.7-1.2-1.0-0.6-0.7
Percentage of Assets-0.1-0.1-0.1-0.3-0.3-0.4-0.2-0.3-0.3-0.3-0.3-0.2-0.2-0.1-0.2-0.2-0.3-0.3-0.4-0.2-0.2-0.1-0.2
Percentage of Assets us-gaap:AccumulatedTranslationAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value2201219422112202219621872203219721902184219221862179217321752167216721612173216321552146215321432151214921462144214521422140213821462144214121402141
Percentage of StockholdersEquity17.418.117.418.318.921.118.018.118.119.119.519.019.119.017.817.818.018.518.217.718.118.718.317.216.816.516.417.017.017.617.917.217.416.917.517.918.5
Percentage of Assets3.33.43.53.53.53.73.63.63.73.73.83.83.83.83.83.83.93.93.93.83.83.93.93.93.93.93.63.73.83.73.73.63.73.73.83.83.9
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value9348908490818796868386349348917191598976927794569216902894149273921190069359918589118770931392709645951593699170949593289110896987748823864385178308
Percentage of StockholdersEquity73.875.171.573.274.683.376.575.675.878.482.782.280.779.076.976.276.677.078.275.375.076.579.274.575.473.071.772.975.176.876.372.371.369.770.871.171.9
Percentage of Assets14.114.314.214.014.014.815.415.215.315.316.216.515.915.716.616.416.416.316.916.215.715.816.916.717.417.115.815.716.616.315.815.315.015.115.315.215.1
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value-73.0-59.0-71.0-71.0-71.0-72.0-70.0-67.0-65.0-64.0-57.0-58.0-58.0-59.0-60.0-61.0-65.0-65.0-73.0-73.0-73.0-73.0-78.0-79.0-84.0-85.0-85.0-85.0-91.0-91.0-91.0-92.0-99.0-99.0-99.0-100.0-102.0
Percentage of StockholdersEquity-0.6-0.5-0.6-0.6-0.6-0.7-0.6-0.6-0.5-0.6-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.6-0.6-0.6-0.6-0.6-0.7-0.6-0.7-0.7-0.7-0.7-0.7-0.7-0.8-0.7-0.8-0.8-0.8-0.8-0.9
Percentage of Assets-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.2-0.2-0.1-0.1-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Cash

us-gaap:Cash

us-gaap:Cash


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
Value462588419442586857242340271223310310288282355283225299271290289242387236145201190247204206195185121123156129100597584848177827214085
Percentage of Cash100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.70.90.70.70.91.50.40.60.50.40.50.50.50.50.60.50.40.50.50.50.50.40.70.40.30.40.30.40.30.40.30.30.20.20.30.20.20.10.10.20.20.00.10.00.00.00.0

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-312016-12-31
Value462588419442586857242340271223310310288355271
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.70.90.70.70.91.50.40.60.50.40.50.50.50.60.5

Short Term Investments

us-gaap:ShortTermInvestments us-gaap:ConsolidatedEntities

us-gaap:ShortTermInvestments

srt:ParentCompany


Short
Period End2020-12-312019-12-312018-12-312017-12-31
Value522521519638
Percentage of ShortTermInvestments100.0100.0100.0100.0
Percentage of Assets0.80.90.91.1
Percentage of Assets srt:ParentCompany3.43.53.74.2

Accumulated Depreciation Depletion And Amortization Property Plant And Equipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value252243231224211224215201208214216208234253274275263255254236224214382387376364364362365367365358379406404408428425420567567543
Percentage of AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.40.40.30.40.40.30.30.40.40.40.40.40.50.50.50.50.50.40.40.40.70.70.70.70.70.60.60.60.60.60.70.70.70.70.80.80.81.01.01.0

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:PropertyPlantAndEquipmentNet


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value234244252256264271282293302314324332347346326325336324310287276263343320317298295287289293304334327323326317310307309324300333
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.40.40.40.40.50.50.50.50.50.60.60.60.60.60.60.60.60.60.50.50.50.60.60.60.50.50.50.50.50.50.60.60.60.60.50.50.50.60.60.50.6

Goodwill

us-gaap:Goodwill

us-gaap:Goodwill


Goodwill
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-31
Value148148148146145145147145146147146147147149148147147146145146147150150151153151152154156155155154152151154123
Percentage of Goodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.20.20.20.20.20.20.20.20.20.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.30.2

us-gaap:Goodwill us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:InternationalSegment


Goodwillus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302019-12-31
Value3131312930
Percentage of Goodwill20.920.920.919.920.4
Percentage of Assets0.00.00.00.00.0
Percentage of Assets us-gaap:OperatingSegments cna:InternationalSegment0.00.00.00.00.0

Indefinite Lived Intangible Assets Excluding Goodwill

us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill

us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill


Indefinite
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-31
Value64626163596871737674747369697316
Percentage of IndefiniteLivedIntangibleAssetsExcludingGoodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.0

us-gaap:IndefiniteLivedIntangibleAssetsExcludingGoodwill us-gaap:IndefiniteLivedIntangibleAssetsByMajorClass

cna:LloydsSyndicateCapacity


Indefinite
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-31
Value484645474352555760585857
Percentage of IndefiniteLivedIntangibleAssetsExcludingGoodwill75.074.273.874.672.976.577.578.178.978.478.478.1
Percentage of Assets0.10.10.10.10.10.10.10.10.10.10.10.1
Percentage of Assets cna:LloydsSyndicateCapacity0.00.00.00.00.00.00.00.00.00.00.00.0

Deferred Tax Assets Liabilities Net

us-gaap:DeferredTaxAssetsLiabilitiesNet

us-gaap:DeferredTaxAssetsLiabilitiesNet


Deferred
Period End2020-12-312019-12-312018-12-312018-01-012017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value66199392158137141166267379221293461638279255571914822033131521938.0127201378205376667
Percentage of DeferredTaxAssetsLiabilitiesNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.30.70.00.20.20.30.50.70.40.50.81.20.50.50.10.30.10.40.60.50.00.20.00.20.40.70.40.71.2

Operating Lease Right Of Use Asset

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:OperatingLeaseRightOfUseAsset


Operating
Period End2020-12-312019-12-31
Value199220
Percentage of OperatingLeaseRightOfUseAsset100.0100.0
Percentage of Assets0.30.4

Equity Securities Fv Ni

us-gaap:EquitySecuritiesFvNi

us-gaap:EquitySecuritiesFvNi


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302017-12-31
Value1033984992919859799865841830814780795773695
Percentage of EquitySecuritiesFvNi100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.61.51.51.51.41.41.41.41.41.41.41.41.31.2

us-gaap:EquitySecuritiesFvNi us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:FairValueInputsLevel1


Equity
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
Value265244243222212246189166180186192152152
Percentage of EquitySecuritiesFvNi25.724.824.524.224.730.821.819.721.722.924.619.119.7
Percentage of Assets0.40.40.40.40.30.40.30.30.30.30.30.30.3
Percentage of Assets us-gaap:FairValueInputsLevel10.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel2


Equity
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
Value743711722674636538658653628608570625604
Percentage of EquitySecuritiesFvNi71.972.372.873.374.067.376.177.675.774.773.178.678.1
Percentage of Assets1.11.11.11.11.00.91.11.11.01.01.01.11.0
Percentage of Assets us-gaap:FairValueInputsLevel20.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel3


Equity
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
Value25292723111518222220181817
Percentage of EquitySecuritiesFvNi2.42.92.72.51.31.92.12.62.72.52.32.32.2
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:FairValueInputsLevel30.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:EquitySecuritiesFvNi us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument

us-gaap:FairValueInputsLevel1, us-gaap:CommonStock


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value198177175157150187135114129136144
Percentage of EquitySecuritiesFvNi19.218.017.617.117.523.415.613.615.516.718.5
Percentage of Assets0.30.30.30.30.20.30.20.20.20.20.3
Percentage of Assets us-gaap:FairValueInputsLevel1 us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel1, us-gaap:PreferredStock


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value6767686562595452515048
Percentage of EquitySecuritiesFvNi6.56.86.97.17.27.46.26.26.16.16.2
Percentage of Assets0.10.10.10.10.10.10.10.10.10.10.1
Percentage of Assets us-gaap:FairValueInputsLevel1 us-gaap:PreferredStock0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel2, us-gaap:PreferredStock


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value743711722674636538658653628608570
Percentage of EquitySecuritiesFvNi71.972.372.873.374.067.376.177.675.774.773.1
Percentage of Assets1.11.11.11.11.00.91.11.11.01.01.0
Percentage of Assets us-gaap:FairValueInputsLevel2 us-gaap:PreferredStock0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel3, us-gaap:CommonStock


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value162120164.04.07.06.06.04.04.0
Percentage of EquitySecuritiesFvNi1.52.12.01.70.50.50.80.70.70.50.5
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:FairValueInputsLevel3 us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:FairValueInputsLevel3, us-gaap:PreferredStock


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value9.08.07.07.07.0111116161614
Percentage of EquitySecuritiesFvNi0.90.80.70.80.81.41.31.91.92.01.8
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:FairValueInputsLevel3 us-gaap:PreferredStock0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:EquitySecuritiesFvNi us-gaap:FinancialInstrument

us-gaap:CommonStock


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value214198195173154191142120135140148
Percentage of EquitySecuritiesFvNi20.720.119.718.817.923.916.414.316.317.219.0
Percentage of Assets0.30.30.30.30.20.30.20.20.20.20.3
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:PreferredStock


Equity
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value819786797746705608723721695674632
Percentage of EquitySecuritiesFvNi79.379.980.381.282.176.183.685.783.782.881.0
Percentage of Assets1.21.21.21.21.11.01.21.21.21.21.1
Percentage of Assets us-gaap:PreferredStock0.00.00.00.00.00.00.00.00.00.00.0

Other Assets

us-gaap:OtherAssets

us-gaap:OtherAssets


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
Value24161813162817881961170814731571174915791208358934263241113312341178129010781070128111241297915961101084189186285596988990710807739118778187799001007868
Percentage of OtherAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.62.82.52.83.22.92.42.62.92.72.16.35.95.62.02.22.12.32.01.92.32.02.41.71.71.81.51.61.51.51.71.61.61.81.31.61.61.51.41.61.81.6

us-gaap:OtherAssets us-gaap:ConsolidatedEntities

srt:ParentCompany


Other
Period End2020-12-312019-12-312018-12-312017-12-31
Value1.01.00.01.0
Percentage of OtherAssets0.10.10.00.1
Percentage of Assets0.00.00.00.0
Percentage of Assets srt:ParentCompany0.00.00.00.0

Long Term Debt

us-gaap:LongTermDebt

us-gaap:LongTermDebt


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value27762679268028582710256225592560257026082651
Percentage of LongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets4.34.44.75.14.94.74.64.54.44.74.8

Long Term Debt Noncurrent

us-gaap:LongTermDebtNoncurrent

us-gaap:LongTermDebtNoncurrent


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value277727772776277626802680267926782678268126802680267926792708270725612560271027092708270822122211256025602559255925582558201125592558255825572557252625262525253826482251
Percentage of LongTermDebtNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets4.24.44.34.44.34.64.44.44.54.64.74.74.64.64.84.84.64.64.94.84.84.94.04.04.74.64.64.64.34.43.54.54.44.44.44.44.54.54.64.54.74.1

us-gaap:LongTermDebtNoncurrent us-gaap:ConsolidatedEntities

srt:ParentCompany


Long
Period End2020-12-312019-12-312018-12-312017-12-31
Value2776267926802678
Percentage of LongTermDebtNoncurrent100.0100.0100.098.9
Percentage of Assets4.34.44.74.7
Percentage of Assets srt:ParentCompany17.917.919.217.7

us-gaap:LongTermDebtNoncurrent us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FairValueByMeasurementBasis

us-gaap:FairValueInputsLevel2, us-gaap:EstimateOfFairValueFairValueDisclosure


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-31
Value30433016314831182953273029062905286427922731273427542786289629162819281129523041302429432433247828432908288328892947290823283016
Percentage of LongTermDebtNoncurrent109.6108.6113.4112.3110.2101.9108.5108.5106.9104.1101.9102.0102.8104.0106.9107.7110.1109.8108.9112.3111.7108.7110.0112.1111.1113.6112.7112.9115.2113.7115.8118.0
Percentage of Assets4.64.74.95.04.84.74.84.84.84.84.84.84.84.85.15.25.05.15.35.35.35.34.44.55.25.25.25.25.05.04.15.2
Percentage of Assets us-gaap:FairValueInputsLevel2 us-gaap:EstimateOfFairValueFairValueDisclosure0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:LongTermDebtNoncurrent us-gaap:FairValueByMeasurementBasis

us-gaap:CarryingReportedAmountFairValueDisclosure


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-31
Value27772777277627762680268026792678267826812680268026792679270827072561256027102709270827082212221125602560255925592558255820112557
Percentage of LongTermDebtNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets4.24.44.34.44.34.64.44.44.54.64.74.74.64.64.84.84.64.64.94.84.84.94.04.04.74.64.64.64.34.43.54.4
Percentage of Assets us-gaap:CarryingReportedAmountFairValueDisclosure0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-31
Value30433016314831182953273029062905286427922731273427542786289629162819281129523041302429432433247828432908288328892947290823283016
Percentage of LongTermDebtNoncurrent109.6108.6113.4112.3110.2101.9108.5108.5106.9104.1101.9102.0102.8104.0106.9107.7110.1109.8108.9112.3111.7108.7110.0112.1111.1113.6112.7112.9115.2113.7115.8118.0
Percentage of Assets4.64.74.95.04.84.74.84.84.84.84.84.84.84.85.15.25.05.15.35.35.35.34.44.55.25.25.25.25.05.04.15.2
Percentage of Assets us-gaap:EstimateOfFairValueFairValueDisclosure0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:LongTermDebtNoncurrent us-gaap:LongtermDebtType

cna:SeniorNotes2050FaceAmountOf500DueAugust152030


Long
Period End2020-12-31
Value495
Percentage of LongTermDebtNoncurrent17.8
Percentage of Assets0.8
Percentage of Assets cna:SeniorNotes2050FaceAmountOf500DueAugust1520300.0

cna:SeniorNotes3.450faceamountof500dueAugust152027


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value4964964954950.0
Percentage of LongTermDebtNoncurrent17.918.518.518.30.0
Percentage of Assets0.80.80.90.90.0
Percentage of Assets cna:SeniorNotes3.450faceamountof500dueAugust1520270.00.00.00.00.0

cna:SeniorNotes3.900faceamountof500dueMay12029


Long
Period End2020-12-312019-12-312018-12-31
Value4964960.0
Percentage of LongTermDebtNoncurrent17.918.50.0
Percentage of Assets0.80.80.0
Percentage of Assets cna:SeniorNotes3.900faceamountof500dueMay120290.00.00.0

cna:SeniorNotes3.950faceamountof550dueMay152024


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value548548547547546547547
Percentage of LongTermDebtNoncurrent19.720.520.420.220.124.721.4
Percentage of Assets0.90.91.01.01.01.01.0
Percentage of Assets cna:SeniorNotes3.950faceamountof550dueMay1520240.00.00.00.00.00.00.0

cna:SeniorNotes4.500faceamountof500dueMarch12026


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value4994984984984980.0
Percentage of LongTermDebtNoncurrent18.018.618.618.418.40.0
Percentage of Assets0.80.80.90.90.90.0
Percentage of Assets cna:SeniorNotes4.500faceamountof500dueMarch120260.00.00.00.00.00.0

us-gaap:SubordinatedDebt


Long
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value242242242242241242241241241
Percentage of LongTermDebtNoncurrent8.79.09.08.98.910.99.412.09.4
Percentage of Assets0.40.40.40.40.40.40.40.40.4
Percentage of Assets us-gaap:SubordinatedDebt0.00.00.00.00.00.00.00.00.0

Lessee Operating Lease Liability Payments Due Year Two

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo


Lessee
Period End2020-12-31
Value41
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearTwo100.0
Percentage of Assets0.1

Lessee Operating Lease Liability Payments Due Year Three

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree


Lessee
Period End2020-12-31
Value36
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearThree100.0
Percentage of Assets0.1

Lessee Operating Lease Liability Payments Due Year Four

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour


Lessee
Period End2020-12-31
Value29
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFour100.0
Percentage of Assets0.0

Lessee Operating Lease Liability Payments Due Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive


Lessee
Period End2020-12-31
Value24
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFive100.0
Percentage of Assets0.0

Lessee Operating Lease Liability Payments Due After Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive


Lessee
Period End2020-12-31
Value163
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive100.0
Percentage of Assets0.3

Operating Lease Liability

us-gaap:OperatingLeaseLiability

us-gaap:OperatingLeaseLiability


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value279301304301308
Percentage of OperatingLeaseLiability100.0100.0100.0100.0100.0
Percentage of Assets0.40.50.50.50.5

Lessee Operating Lease Liability Payments Due

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue


Lessee
Period End2020-12-31
Value337
Percentage of LesseeOperatingLeaseLiabilityPaymentsDue100.0
Percentage of Assets0.5

Lessee Operating Lease Liability Undiscounted Excess Amount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount


Lessee
Period End2020-12-31
Value58
Percentage of LesseeOperatingLeaseLiabilityUndiscountedExcessAmount100.0
Percentage of Assets0.1

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value126681208912707120211164510362122151212312087114551121711510114151142512244121691202811693119691219511886114701175612265122341243712794130341307412582126511215311944124051231412660122141198111557118081160210954
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets19.119.019.819.118.817.720.220.120.219.619.620.119.719.821.621.521.421.221.721.420.920.721.422.422.222.423.023.422.021.622.121.320.721.121.021.621.621.420.921.120.819.8

us-gaap:StockholdersEquity us-gaap:ConsolidatedEntities

srt:ParentCompany


Stockholders
Period End2020-12-312019-12-312018-12-312017-12-31
Value12707122151121712244
Percentage of StockholdersEquity100.0100.0100.0100.0
Percentage of Assets19.820.219.621.6
Percentage of Assets srt:ParentCompany81.981.880.481.0

us-gaap:StockholdersEquity us-gaap:CumulativeEffectPeriodOfAdoption, us-gaap:StatementEquityComponents

srt:CumulativeEffectPeriodOfAdoptionAdjustedBalance, us-gaap:RetainedEarnings


Stockholders
Period End2021-03-312020-12-312020-06-302020-03-312019-12-312019-06-302019-03-312018-12-312017-12-31
Value908490818683863493439159897692779364
Percentage of StockholdersEquity75.171.574.683.376.575.878.482.776.5
Percentage of Assets14.314.214.014.815.415.315.316.216.6
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustedBalance us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.0

srt:CumulativeEffectPeriodOfAdoptionAdjustment, us-gaap:RetainedEarnings


Stockholders
Period End2020-12-312019-12-312017-12-31
Value-5.0-5.0-50.0
Percentage of StockholdersEquity-0.0-0.0-0.4
Percentage of Assets-0.0-0.0-0.1
Percentage of Assets srt:CumulativeEffectPeriodOfAdoptionAdjustment us-gaap:RetainedEarnings0.00.00.0

us-gaap:StockholdersEquity us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents

us-gaap:OtherInvestments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2021-06-302021-03-312020-12-312020-06-302020-03-312019-12-31
Value1418111817451172-19.01025
Percentage of StockholdersEquity11.29.213.710.1-0.28.4
Percentage of Assets2.11.82.71.9-0.01.7
Percentage of Assets us-gaap:OtherInvestments us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.0

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value-829.0-839.0-848.0-808.0-815.0-822.0-833.0-753.0-760.0-768.0-775.0-751.0-758.0-765.0-645.0-625.0-635.0-640.0-647.0-631.0-637.0-642.0-648.0
Percentage of StockholdersEquity-6.5-6.9-6.7-6.7-7.0-7.9-6.8-6.2-6.3-6.7-6.9-6.5-6.6-6.7-5.3-5.1-5.3-5.5-5.4-5.2-5.4-5.6-5.5
Percentage of Assets-1.3-1.3-1.3-1.3-1.3-1.4-1.4-1.2-1.3-1.3-1.4-1.3-1.3-1.3-1.1-1.1-1.1-1.2-1.2-1.1-1.1-1.2-1.2
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Stockholders
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value13791172-19.010101064102358761113271430750809786709642976934624390
Percentage of StockholdersEquity11.510.1-0.28.38.88.55.10.51.02.43.86.16.66.56.15.48.07.95.43.3
Percentage of Assets2.21.9-0.01.71.81.71.00.10.20.50.71.31.41.41.31.21.71.61.10.7
Percentage of Assets us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value509187803411154-1070.051139120-324.0-878.0-757.0-605.0-400.03210732-92.0-173.0237210-56.0-315.04214007739626924421131267278311130867764480
Percentage of StockholdersEquity4.01.56.33.41.3-10.30.41.11.0-2.8-7.8-6.6-5.3-3.50.30.90.3-0.8-1.41.91.8-0.5-2.73.43.15.97.45.53.50.91.15.96.78.97.16.44.2
Percentage of Assets0.80.31.30.70.2-1.80.10.20.2-0.6-1.5-1.3-1.0-0.70.10.20.1-0.2-0.30.40.4-0.1-0.60.80.71.41.61.20.80.20.21.21.41.91.51.40.9
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherThanTemporaryImpairment


Stockholders
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value-3.0-9.0-11.01520202016192021252726263034313227
Percentage of StockholdersEquity-0.0-0.1-0.10.10.20.20.20.10.20.20.20.20.20.20.20.30.30.30.30.2
Percentage of Assets-0.0-0.0-0.00.00.00.00.00.00.00.00.00.00.00.00.00.10.10.10.10.0
Percentage of Assets us-gaap:AccumulatedOtherThanTemporaryImpairment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedTranslationAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value-80.0-92.0-94.0-157.0-194.0-218.0-141.0-192.0-163.0-163.0-180.0-138.0-138.0-86.0-98.0-104.0-145.0-187.0-198.0-142.0-118.0-70.0-84.0
Percentage of StockholdersEquity-0.6-0.8-0.7-1.3-1.7-2.1-1.2-1.6-1.3-1.4-1.6-1.2-1.2-0.8-0.8-0.9-1.2-1.6-1.7-1.2-1.0-0.6-0.7
Percentage of Assets-0.1-0.1-0.1-0.3-0.3-0.4-0.2-0.3-0.3-0.3-0.3-0.2-0.2-0.1-0.2-0.2-0.3-0.3-0.4-0.2-0.2-0.1-0.2
Percentage of Assets us-gaap:AccumulatedTranslationAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value2201219422112202219621872203219721902184219221862179217321752167216721612173216321552146215321432151214921462144214521422140213821462144214121402141
Percentage of StockholdersEquity17.418.117.418.318.921.118.018.118.119.119.519.019.119.017.817.818.018.518.217.718.118.718.317.216.816.516.417.017.017.617.917.217.416.917.517.918.5
Percentage of Assets3.33.43.53.53.53.73.63.63.73.73.83.83.83.83.83.83.93.93.93.83.83.93.93.93.93.93.63.73.83.73.73.63.73.73.83.83.9
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value9348908490818796868386349348917191598976927794569216902894149273921190069359918589118770931392709645951593699170949593289110896987748823864385178308
Percentage of StockholdersEquity73.875.171.573.274.683.376.575.675.878.482.782.280.779.076.976.276.677.078.275.375.076.579.274.575.473.071.772.975.176.876.372.371.369.770.871.171.9
Percentage of Assets14.114.314.214.014.014.815.415.215.315.316.216.515.915.716.616.416.416.316.916.215.715.816.916.717.417.115.815.716.616.315.815.315.015.115.315.215.1
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value-73.0-59.0-71.0-71.0-71.0-72.0-70.0-67.0-65.0-64.0-57.0-58.0-58.0-59.0-60.0-61.0-65.0-65.0-73.0-73.0-73.0-73.0-78.0-79.0-84.0-85.0-85.0-85.0-91.0-91.0-91.0-92.0-99.0-99.0-99.0-100.0-102.0
Percentage of StockholdersEquity-0.6-0.5-0.6-0.6-0.6-0.7-0.6-0.6-0.5-0.6-0.5-0.5-0.5-0.5-0.5-0.5-0.5-0.6-0.6-0.6-0.6-0.6-0.7-0.6-0.7-0.7-0.7-0.7-0.7-0.7-0.8-0.7-0.8-0.8-0.8-0.8-0.9
Percentage of Assets-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.2-0.2-0.1-0.1-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2-0.2
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Additional Paid In Capital Common Stock

us-gaap:AdditionalPaidInCapitalCommonStock

us-gaap:AdditionalPaidInCapitalCommonStock


Additional
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value220121942211220221962187220321972190218421922186217921732175216721672161217321632155214621532150214621432151214921462144214521422140213821462144214121402146214421432200
Percentage of AdditionalPaidInCapitalCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.33.43.53.53.53.73.63.63.73.73.83.83.83.83.83.83.93.93.93.83.83.93.93.93.93.93.93.93.63.73.83.73.73.63.73.73.83.83.93.83.84.0

us-gaap:AdditionalPaidInCapitalCommonStock us-gaap:ConsolidatedEntities

srt:ParentCompany


Additional
Period End2020-12-312019-12-312018-12-312017-12-31
Value2211220321922175
Percentage of AdditionalPaidInCapitalCommonStock100.0100.0100.0100.0
Percentage of Assets3.53.63.83.8
Percentage of Assets srt:ParentCompany14.214.715.714.4

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:RetainedEarningsAccumulatedDeficit


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value934890849081879686838634934891719159897692779456921690289414927392119006935991858911877093139450934092709645951593699170949593289110896987748823864385178382821981717876
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets14.114.314.214.014.014.815.415.215.315.316.216.515.915.716.616.416.416.316.916.215.715.816.917.217.016.717.417.115.815.716.616.315.815.315.015.115.315.215.214.714.714.2

us-gaap:RetainedEarningsAccumulatedDeficit us-gaap:ConsolidatedEntities

srt:ParentCompany


Retained
Period End2020-12-312019-12-312018-12-312017-12-31
Value9081934892779414
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0
Percentage of Assets14.215.416.216.6
Percentage of Assets srt:ParentCompany58.562.666.562.2

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value509187803411154-1070.051139120-324.0-878.0-757.0-605.0-400.03210732-92.0-173.0237210-56.0-315.0601434214007739626924421131267278311130867764470886730326
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.80.31.30.70.2-1.80.10.20.2-0.6-1.5-1.3-1.0-0.70.10.20.1-0.2-0.30.40.4-0.1-0.60.10.30.80.71.41.61.20.80.20.21.21.41.91.51.40.91.61.30.6

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax us-gaap:ConsolidatedEntities

srt:ParentCompany


Accumulated
Period End2020-12-312019-12-312018-12-312017-12-31
Value80351-878.032
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0
Percentage of Assets1.30.1-1.50.1
Percentage of Assets srt:ParentCompany5.20.3-6.30.2

Treasury Stock Value

us-gaap:TreasuryStockValue

us-gaap:TreasuryStockValue


Treasury
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
Value73597171717270676564575858596061656573737373787878798485858591919192999999100102102102105
Percentage of TreasuryStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.20.20.10.10.20.20.20.20.20.20.20.20.20.20.20.2

us-gaap:TreasuryStockValue us-gaap:ConsolidatedEntities

srt:ParentCompany


Treasury
Period End2020-12-312019-12-312018-12-312017-12-31
Value71705760
Percentage of TreasuryStockValue100.0100.0100.0100.0
Percentage of Assets0.10.10.10.1
Percentage of Assets srt:ParentCompany0.50.50.40.4

Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap:StatementEquityComponents

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:AdditionalPaidInCapital


Adjustments
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
Value7.0-17.09.06.09.0-16.06.07.06.0-8.06.07.06.0-2.08.00.06.0-12.0
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock


Adjustments
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
Value1.0150.00.01.0162.00.01.07.01.00.01.01.01.04.00.08.0
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue14.3-88.20.00.011.1-100.033.30.016.7-87.516.70.016.7-50.012.50.00.0-66.7
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value6038236775843821216046622728735951413621836037923328229650727933434250544694393460419168283352378191257375306312889401300112584-1254.0
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax168.024.312.5239.1142.270.45.8159.679.6102.114.9199.25.38.614.715.89.812.112.420.811.915.215.123.519.24.016.519.117.26.810.814.115.27.610.615.213.613.039.418.413.64.825.4-53.1

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-610.0408-298.0-882.0-612.01087-165.0-293.0-56.0289-257.0-359.0-50.0489-206.0-329.0-243.0354-242.0-437.0-158.0-9.0-118.0-341.0-439.0526169-353.0-380.0-354.0-209.0-218.0-310.0-161.0-187.0-237.0-223.0-287.0-843.0-314.0171-74.0-93.01383
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-169.9120.7-10.2-278.2-198.7361.1-5.9-100.3-19.6102.8-10.7-139.1-1.919.3-8.4-13.7-10.315.2-10.1-18.0-6.7-0.4-5.2-15.8-18.922.47.1-14.6-15.6-14.4-8.0-8.7-12.4-6.4-7.7-9.6-9.9-12.0-37.3-14.47.8-3.2-4.058.5

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-120.0-321.0-101.0-25.0-101.0-675.0-101.0-99.0-123.0-665.0-96.0-134.0-74.0-781.0-82.04.0-68.0-609.0-68.0-67.0-69.0-469.0-68.0-69.0-67.0-603.0-614.0-68.0-47.0210-64.0-73.0-71.0-56.0-44.0-112.0-41.0-42.0-56.0-84.0-468.0-36.0-497.0-121.0
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-33.4-95.0-3.4-7.9-32.8-224.3-3.6-33.9-43.2-236.7-4.0-51.9-2.9-30.8-3.30.2-2.9-26.1-2.8-2.8-2.9-21.4-3.0-3.2-2.9-25.6-25.8-2.8-1.98.5-2.4-2.9-2.8-2.2-1.8-4.5-1.8-1.7-2.5-3.9-21.3-1.6-21.6-5.1

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

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value-126.0169-23.0-144.0-271.0615-98.06948-87.00.0
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-35.150.0-0.8-45.4-88.0204.3-3.523.616.8-31.00.0

Deferred Income Tax Expense Benefit

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DeferredIncomeTaxExpenseBenefit


Deferred
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-3.030-8.0-8.04.0-37.026-97.0-7.03224498.055-177.0-5.0-39.071-80.0332325-64.019239952148.07339559.08916481
Percentage of DeferredIncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Depreciation Depletion And Amortization

us-gaap:DepreciationDepletionAndAmortization

us-gaap:DepreciationDepletionAndAmortization


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-31
Value131414151516161617192018212022232221201818212223201921202220212225334244192020
Percentage of DepreciationDepletionAndAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value6038236775843821216046622728735951413621836037923328229650727933434250544694393460419168283352378191257375306312889401300112584-1254.0
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax168.024.312.5239.1142.270.45.8159.679.6102.114.9199.25.38.614.715.89.812.112.420.811.915.215.123.519.24.016.519.117.26.810.814.115.27.610.615.213.613.039.418.413.64.825.4-53.1

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
Value368312387213151-61.0273107278342-84.033627029122314427226024134320966-70.017813823319821326713221272194250-9.022116625019075126223302-140.0283245
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 RevenueFromContractWithCustomerExcludingAssessedTax102.592.313.267.249.0-20.39.836.697.5121.7-3.5130.210.511.59.16.011.511.210.114.18.93.0-3.18.35.99.98.38.810.90.58.510.97.810.0-0.49.07.410.48.43.45.79.613.1-5.912.710.6

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value368312387213151-61.0273107278342-84.03362702912231442722602413432096623319821326713221272194250-9.0221166250
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax102.592.313.267.249.0-20.39.836.697.5121.7-3.5130.210.511.59.16.011.511.210.114.18.93.09.98.38.810.90.58.510.97.810.0-0.49.07.410.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-610.0408-298.0-882.0-612.01087-165.0-293.0-56.0289-257.0-359.0-50.0489-206.0-329.0-243.0354-242.0-437.0-158.0-9.0-118.0-341.0-439.0526169-353.0-380.0-354.0-209.0-218.0-310.0-161.0-187.0-237.0-223.0-287.0-843.0-314.0171-74.0-93.01383
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-169.9120.7-10.2-278.2-198.7361.1-5.9-100.3-19.6102.8-10.7-139.1-1.919.3-8.4-13.7-10.315.2-10.1-18.0-6.7-0.4-5.2-15.8-18.922.47.1-14.6-15.6-14.4-8.0-8.7-12.4-6.4-7.7-9.6-9.9-12.0-37.3-14.47.8-3.2-4.058.5

Payments To Acquire Property Plant And Equipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment


Payments
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
Value2.03.07.06.07.03.06.06.06.08.01211383822123830522932334127372029151710.02425212134182022174313111515
Percentage of PaymentsToAcquirePropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-120.0-321.0-101.0-25.0-101.0-675.0-101.0-99.0-123.0-665.0-96.0-134.0-74.0-781.0-82.04.0-68.0-609.0-68.0-67.0-69.0-469.0-68.0-69.0-67.0-603.0-614.0-68.0-47.0210-64.0-73.0-71.0-56.0-44.0-112.0-41.0-42.0-56.0-84.0-468.0-36.0-497.0-121.0
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-33.4-95.0-3.4-7.9-32.8-224.3-3.6-33.9-43.2-236.7-4.0-51.9-2.9-30.8-3.30.2-2.9-26.1-2.8-2.8-2.9-21.4-3.0-3.2-2.9-25.6-25.8-2.8-1.98.5-2.4-2.9-2.8-2.2-1.8-4.5-1.8-1.7-2.5-3.9-21.3-1.6-21.6-5.1

Proceeds From Issuance Of Long Term Debt

us-gaap:ProceedsFromIssuanceOfLongTermDebt

us-gaap:ProceedsFromIssuanceOfLongTermDebt


Proceeds
Period End2020-12-312020-09-302019-12-312019-09-302018-12-312018-09-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.04950.00.00.00.00.04960.00.00.00.00.04980.00.00.00.00.00.00.05460.00.00.03960.0495
Percentage of ProceedsFromIssuanceOfLongTermDebt0.0100.00.00.00.00.00.0100.00.00.00.00.00.0100.00.00.00.00.00.00.00.0100.00.00.00.0100.00.0100.0

Repayments Of Long Term Debt

us-gaap:RepaymentsOfLongTermDebt

us-gaap:RepaymentsOfLongTermDebt


Repayments
Period End2020-12-312020-09-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312013-12-312012-12-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value0.04190.00.05200.00.0300.01500.03910.00.00.00.00.03580.00.00.00.00.00.031110.04090.0100
Percentage of RepaymentsOfLongTermDebt0.0100.00.00.0100.00.00.0100.00.0100.00.0100.00.00.00.00.00.0100.00.00.00.00.00.00.0100.0100.00.0100.00.0100.0

Payments Of Dividends Common Stock

us-gaap:PaymentsOfDividendsCommonStock

us-gaap:PaymentsOfDividendsCommonStock


Payments
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
Value104310100100101649959695643959582624818567609676968609676868608686768338545453554041404127272727
Percentage of PaymentsOfDividendsCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Payments For Repurchase Of Common Stock

us-gaap:PaymentsForRepurchaseOfCommonStock

us-gaap:PaymentsForRepurchaseOfCommonStock


Payments
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
Value153.00.00.00.0185.02.02.0140.00.00.00.0
Percentage of PaymentsForRepurchaseOfCommonStock100.0100.00.00.00.0100.0100.0100.0100.0100.00.00.00.00.0

cna:ChangeInOtherInvestments

cna:ChangeInOtherInvestments


Change
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value8.0-2.0-4.0-2.04.0-6.0-3.0-4.02.0-6.0-2.0-4.0-2.0-4.0-1.01.0-2.0-1.0-3.0-1.0110.0-1.0-3.01.07.05.00.010.00.0-3.03.0-13.0223.010.0-4.0-6.0-88.0-43.0-36.0-28.0
Percentage of ChangeInOtherInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:ChangeInShortTermInvestments

cna:ChangeInShortTermInvestments


Change
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-131.0573-442.0-6.0-858.01267-355.031-34.0-177.010.023-73.020823-110.0-190.027117-40.026516-188.0189-157.019016812210.0-688.0686429264498-382.0-115.0-8.067-15.0-34.0548-123.0963
Percentage of ChangeInShortTermInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CostsFromContractWithCustomers

cna:CostsFromContractWithCustomers


Costs
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value33231130029328528128127826326024723522521683747270
Percentage of CostsFromContractWithCustomers100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CostsFromContractWithCustomers us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:SpecialtySegment


Costs
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value332311300293285281281278
Percentage of CostsFromContractWithCustomers100.0100.0100.0100.0100.0100.0100.0100.0

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss


Fair
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
Value26-60.0181473-49.0-5.0151613-5.0-1.0-3.0-1.01.03.03.011
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
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
Value5.0-7.0-1.09.018-9.00.01.04.03.0-2.0-2.0-1.02.00.01.02.02.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss19.211.7-5.664.324.718.4-0.06.725.023.140.0200.033.3-200.00.033.366.718.2

us-gaap:CorporateDebtSecurities


Fair
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
Value19-53.0175.059-37.0-1.014128.0-3.00.0-1.0-1.00.02.00.01.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss73.188.394.435.780.875.520.093.375.061.560.0-0.033.3100.00.066.70.09.1

us-gaap:EquitySecurities


Fair
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
Value0.02.01.00.0-4.0-3.0-4.00.00.02.00.01.0-1.0-2.01.00.01.01.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss0.0-3.35.60.0-5.56.180.00.00.015.4-0.0-100.033.3200.0100.00.033.39.1

us-gaap:USStatesAndPoliticalSubdivisions


Fair
Period End2021-06-302021-03-312020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value2.0-2.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss7.73.3-0.0-0.00.00.00.0-0.0-0.0-0.0-0.00.00.00.00.0

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome us-gaap:FairValueByAssetClass, us-gaap:IncomeStatementLocation

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome

us-gaap:AssetBackedSecurities, cna:OtherRevenues


Fair
Period End2021-06-302021-03-312020-06-302020-03-312019-06-302019-03-31
Value1000000.02000000.00000
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome100.0100.00.00.00.00.0

us-gaap:EquitySecurities, cna:OtherRevenues


Fair
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-06-302019-03-31
Value01000000.01000000.000-3000000.000
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome0.050.00.00.00.00.00.00.0

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome us-gaap:IncomeStatementLocation

cna:OtherRevenues


Fair
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-06-302019-03-31
Value1000000.03000000.000-3000000.000
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome100.0150.00.00.00.00.00.0

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss


Fair
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
Value22-51.0141376-44.0-3.0161510.0-5.01.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
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
Value4.0-9.0-1.08.018-9.0-2.02.05.03.0-2.01.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss18.217.6-7.161.523.720.566.712.533.330.040.0100.0

us-gaap:CorporateDebtSecurities


Fair
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
Value16-40.0145.058-35.0-1.01410.07.0-3.00.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss72.778.4100.038.576.379.533.387.566.770.060.00.0

us-gaap:USStatesAndPoliticalSubdivisions


Fair
Period End2021-06-302021-03-312020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value2.0-2.00.00.00.00.00.00.00.0
Percentage of FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss9.13.9-0.0-0.00.00.00.0-0.00.0

cna:IncomeTaxExpenseBenefitOnNetRealizedInvestmentGainsLosses

cna:IncomeTaxExpenseBenefitOnNetRealizedInvestmentGainsLosses


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value118.0147.017-47.01.02.0-2.07.0-16.01.0-1.02.011-9.017114.0148.0-11.0-10.0-17.0-6.02.0-5.010.0-3.0165.01.0-4.09.0-1.03.08.012-4.0-10.05.04.0
Percentage of IncomeTaxExpenseBenefitOnNetRealizedInvestmentGainsLosses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:IncomeTaxExpenseBenefitOnOperatingIncomeLoss

cna:IncomeTaxExpenseBenefitOnOperatingIncomeLoss


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value83587730141961186670-14.07161539352817272118712.0-81.07232785974106627310286104-26.0905610254584297
Percentage of IncomeTaxExpenseBenefitOnOperatingIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:IncomeTaxExpenseBenefitOnOperatingIncomeLoss us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value3418431410.08.03727
Percentage of IncomeTaxExpenseBenefitOnOperatingIncomeLoss41.031.055.846.771.442.160.7150.0

us-gaap:OperatingSegments, cna:InternationalSegment


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-31
Value10.05.09.0-1.0-3.07.0
Percentage of IncomeTaxExpenseBenefitOnOperatingIncomeLoss12.08.611.7-3.3-21.411.5

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Income
Period End2021-06-302021-03-312020-06-302020-03-31
Value-2.0-4.0-11.0-14.0
Percentage of IncomeTaxExpenseBenefitOnOperatingIncomeLoss-2.4-6.9-78.6-73.7

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Income
Period End2020-09-302019-09-30
Value-24.0-48.0
Percentage of IncomeTaxExpenseBenefitOnOperatingIncomeLoss-80.0-266.7

us-gaap:OperatingSegments, cna:SpecialtySegment


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value5346474526275243
Percentage of IncomeTaxExpenseBenefitOnOperatingIncomeLoss63.979.361.0150.0185.7142.185.2238.9

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Income
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-12.0-7.0-15.0-4.00.0-2.0-19.0-4.0-1.0-2.0-9.0-4.0-9.0-17.0-9.0-13.0-15.0-23.0-10.0-15.0-11.0-62.0
Percentage of IncomeTaxExpenseBenefitOnOperatingIncomeLoss-14.5-12.1-19.5-13.30.0-10.5-31.1-22.2-1.5-2.964.3-5.6-14.8-32.1-9.7-25.0-18.5-31.9-13.9-12.7-15.5-3100.0

cna:Insuranceclaimsandpolicyholdersbenefitsincludingpolicyholdersdividends

cna:Insuranceclaimsandpolicyholdersbenefitsincludingpolicyholdersdividends


Insuranceclaimsandpolicyholdersbenefitsincludingpolicyholdersdividends
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value1546150614871616164214251483161413521357159413121327133912571480128012931334120213391408137612001469133913501354144114461547137814851396
Percentage of Insuranceclaimsandpolicyholdersbenefitsincludingpolicyholdersdividends100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:InvestmentsandDerivativesRealizedGainLoss

cna:InvestmentsandDerivativesRealizedGainLoss


Investmentsand
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value3857662769-216.09.07.0-18.031-77.014-1.01231-24.050
Percentage of InvestmentsandDerivativesRealizedGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCtaAndOther

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCtaAndOther


Liability
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value27-32.0847453-88.054-26.04213-49.0-10.0-61.0-9.053405614-90.0-7.07.039
Percentage of LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCtaAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsAmortizationOfDiscount

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsAmortizationOfDiscount


Liability
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value45504045475141454850404445474145454841414548
Percentage of LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsAmortizationOfDiscount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease


Liability
Period End2020-09-30
Value-37000000.0
Percentage of LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease100.0

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease

cna:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease


Liability
Period End2020-09-30
Value46
Percentage of LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease100.0

cna:LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease

cna:LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease


Liabilityfor
Period End2020-09-30
Value-37000000.0
Percentage of LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease100.0

cna:LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease

cna:LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease


Liabilityfor
Period End2020-09-30
Value46
Percentage of LiabilityforUnpaidClaimsandClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease100.0

cna:NetInvestmentIncomeAndGainsLossesOnTradingSecurities

cna:NetInvestmentIncomeAndGainsLossesOnTradingSecurities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value591504555517534329545487515571334487506490505509475545527524502435428354500558511480550526642597578633563601470648523394517620
Percentage of NetInvestmentIncomeAndGainsLossesOnTradingSecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:NetInvestmentIncomeAndGainsLossesOnTradingSecurities us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value17414817616516142174136
Percentage of NetInvestmentIncomeAndGainsLossesOnTradingSecurities29.429.431.731.930.112.831.927.9

us-gaap:OperatingSegments, cna:InternationalSegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1414141514151617
Percentage of NetInvestmentIncomeAndGainsLossesOnTradingSecurities2.42.82.52.92.64.62.93.5

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Net
Period End2021-06-302021-03-312020-06-302020-03-31
Value265219206208
Percentage of NetInvestmentIncomeAndGainsLossesOnTradingSecurities44.843.538.663.2

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Net
Period End2020-09-302019-09-30
Value208207
Percentage of NetInvestmentIncomeAndGainsLossesOnTradingSecurities40.242.5

us-gaap:OperatingSegments, cna:SpecialtySegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value13411713412613356146121
Percentage of NetInvestmentIncomeAndGainsLossesOnTradingSecurities22.723.224.124.424.917.026.824.8

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value4.06.02.03.04.03.05.06.07.07.04.05.06.05.05.06.04.05.05.04.04.03.0
Percentage of NetInvestmentIncomeAndGainsLossesOnTradingSecurities0.71.20.40.60.70.90.91.21.41.21.21.01.21.01.01.20.80.90.90.80.80.7

cna:NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent

cna:NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value34126333519399108265102294318-23.031727028128615923923522131120191
Percentage of NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1376916552492313397
Percentage of NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent40.226.249.326.949.521.350.295.1

us-gaap:OperatingSegments, cna:InternationalSegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value26242327-14.02.016-9.0
Percentage of NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent7.69.16.914.0-14.11.96.0-8.8

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Net
Period End2021-06-302021-03-312020-06-302020-03-31
Value4336144.0
Percentage of NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent12.613.714.13.7

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Net
Period End2020-09-302019-09-30
Value-35.0-122.0
Percentage of NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent-18.1-119.6

us-gaap:OperatingSegments, cna:SpecialtySegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1881701811689096188153
Percentage of NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent55.164.654.087.090.988.970.9150.0

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-53.0-36.0-60.0-19.0-11.0-18.0-68.0-17.0-11.0-6.0-46.0-20.0-39.0-60.0-8.0-18.0-27.0-37.0-16.0-24.0-24.0-114.0
Percentage of NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent-15.5-13.7-17.9-9.8-11.1-16.7-25.7-16.7-3.7-1.9200.0-6.3-14.4-21.4-2.8-11.3-11.3-15.7-7.2-7.7-11.9-125.3

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCasualty us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCasualty

cna:InternationalSegment


Net
Period End2021-06-302020-06-30
Value1000000.0-6000000.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCasualty100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto

cna:CommercialSegment


Net
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value300.09.0159.0-1.0-16.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto100.00.0100.0100.0100.0100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability

cna:CommercialSegment


Net
Period End2020-12-312020-09-302019-12-312019-09-30
Value0.0151843
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability0.0100.0100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability

cna:InternationalSegment


Net
Period End2020-12-312020-09-302019-12-312019-09-30
Value-2.0-5.0-9.0-6.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability100.0100.0100.0100.0

cna:SpecialtySegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value0.08.00.0250.010.01629
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability0.00.0-0.0-500.00.00.0-177.8-483.3

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentOther us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentOther

cna:SpecialtySegment


Net
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value3.0-2.0-1.0-8.06.0-1.012
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentOther100.0100.0100.0100.0100.0100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyAndOther us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyAndOther

cna:CommercialSegment


Net
Period End2021-06-302020-12-312020-09-302020-06-302019-12-312019-09-30
Value120.00.041-19.01.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyAndOther100.00.00.0100.0100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSpecialty us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSpecialty

cna:InternationalSegment


Net
Period End2021-06-302020-06-30
Value1000000.02000000.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSpecialty100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety

cna:SpecialtySegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value-23.0-15.01.0-40.00.0-30.0-9.0-43.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety100.0100.0100.0100.00.0100.0100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWarranty us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWarranty

cna:SpecialtySegment


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302019-12-31
Value0-8000000.0-4000000.00-3000000.0-8000000.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWarranty0.0100.0100.00.0100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation

cna:CommercialSegment


Net
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value-42.01.0-23.0-61.0-13.0-15.07.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation100.0100.0100.0100.0100.0100.0100.0

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReservePropertyEnergyAndMarine us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReservePropertyEnergyAndMarine

cna:InternationalSegment


Net
Period End2021-06-302020-06-30
Value-3000000.01000000.0
Percentage of NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReservePropertyEnergyAndMarine100.0100.0

cna:NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentOtherProfessionalLiability us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentOtherProfessionalLiability

cna:InternationalSegment


Net
Period End2020-12-312020-09-302019-12-312019-09-30
Value3.09.02.04.0
Percentage of NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentOtherProfessionalLiability100.0100.0100.0100.0

cna:NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyMarine us-gaap:StatementBusinessSegments

cna:NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyMarine

cna:InternationalSegment


Net
Period End2020-12-312020-09-302019-12-312019-09-30
Value0.0-4.0143.0
Percentage of NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyMarine0.0100.0100.0100.0

cna:NetRealizedInvestmentGainsLosses

cna:NetRealizedInvestmentGainsLosses


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value2749522052-169.08.05.0-16.024-61.0130.010.020-15.0332520328.0-25.0-18.0-32.06.08.0-7.027-11.0308.03.0-10.016-2.05.014
Percentage of NetRealizedInvestmentGainsLosses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:NetRealizedInvestmentGainsLossesContinuingAndDiscontinuingOperations

cna:NetRealizedInvestmentGainsLossesContinuingAndDiscontinuingOperations


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value3857662769-216.09.07.0-18.031-77.014-1.01231-24.05036244616-36.0-28.0-49.00.010.0-12.038-13.047134.0-14.028
Percentage of NetRealizedInvestmentGainsLossesContinuingAndDiscontinuingOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability us-gaap:StatementBusinessSegments

cna:NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability

cna:SpecialtySegment


Netprioryearclaimandallocatedclaimadjustmentexpensereservedevelopment
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value10.0-9.00.0-9.03.0-32.0-18.0
Percentage of NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability100.0100.00.0100.0100.0100.0100.0

cna:OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax

cna:OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax


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
Value424321412223113127326120360388-37.038833133437921132030729342927293-133.0282164303264256378252286371290335-33.0306208328251151161318
Percentage of OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value17187208665931170124
Percentage of OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax40.327.150.529.652.224.452.1103.3

us-gaap:OperatingSegments, cna:InternationalSegment


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value36293226-17.02.023-9.0
Percentage of OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax8.59.07.811.7-15.01.67.1-7.5

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Operating
Period End2021-06-302021-03-312020-06-302020-03-31
Value41323.0-10.0
Percentage of OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax9.710.02.7-7.9

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Operating
Period End2020-09-302019-09-30
Value-59.0-170.0
Percentage of OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax-26.5-141.7

us-gaap:OperatingSegments, cna:SpecialtySegment


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value241216228213116123240196
Percentage of OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax56.867.355.395.5102.796.973.6163.3

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-65.0-43.0-75.0-23.0-11.0-20.0-87.0-21.0-12.0-8.0-55.0-24.0-48.0-77.0-17.0-31.0-42.0-60.0-26.0-39.0-35.0-176.0
Percentage of OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax-15.3-13.4-18.2-10.3-9.7-15.7-26.7-17.5-3.3-2.1148.6-6.2-14.5-23.1-4.5-14.7-13.1-19.5-8.9-9.1-12.9-189.2

cna:OperatingRevenues

cna:OperatingRevenues


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
Value299128092865279326972507276826782628266424802608257525232417242223162294236623872332223122972202232723422390237424542417260025002507247524372458222423652264220221832302
Percentage of OperatingRevenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:OperatingRevenues us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-1.0-2.0-2.0-1.0-1.0-2.0-1.0-2.0-1.0-3.0-1.0-1.00.0-1.00.00.0-1.00.00.00.0-1.00.0
Percentage of OperatingRevenues-0.0-0.1-0.1-0.0-0.0-0.1-0.0-0.1-0.0-0.1-0.0-0.00.0-0.00.00.0-0.00.00.00.0-0.00.0

cna:OperatingRevenues us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value10601008103610289618681006959
Percentage of OperatingRevenues35.435.936.236.835.634.636.335.8

us-gaap:OperatingSegments, cna:InternationalSegment


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value281266255251238254261252
Percentage of OperatingRevenues9.49.58.99.08.810.19.49.4

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Operating
Period End2021-06-302021-03-312020-06-302020-03-31
Value390340332335
Percentage of OperatingRevenues13.012.112.313.4

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Operating
Period End2020-09-302019-09-30
Value335336
Percentage of OperatingRevenues12.012.5

us-gaap:OperatingSegments, cna:SpecialtySegment


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value12551190121911771146104311611126
Percentage of OperatingRevenues42.042.442.542.142.541.641.942.0

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value6.07.04.03.05.05.07.07.09.09.0217.05.06.06.06.05.05.0144.04.06.0
Percentage of OperatingRevenues0.20.20.10.10.20.20.30.30.30.30.80.30.20.20.20.20.20.20.60.20.20.3

cna:OtherInsuranceRelatedExpenses

cna:OtherInsuranceRelatedExpenses


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value27125525925126025827225725825126026623627730228126125428029527027730326325926824826025926224925325326228326824825012252257217
Percentage of OtherInsuranceRelatedExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:OtherInsuranceRelatedExpenses us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Other
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value0.0-1.00.00.00.0-1.00.0-1.00.0-1.00.00.00.00.0-1.00.00.00.0-1.00.0
Percentage of OtherInsuranceRelatedExpenses0.0-0.40.00.00.0-0.40.0-0.40.0-0.40.00.00.00.0-0.40.00.00.0-0.40.0

cna:OtherInsuranceRelatedExpenses us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value136115127127124127133123
Percentage of OtherInsuranceRelatedExpenses50.245.149.050.647.749.248.947.9

us-gaap:OperatingSegments, cna:InternationalSegment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value3935303139363635
Percentage of OtherInsuranceRelatedExpenses14.413.711.612.415.014.013.213.6

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Other
Period End2021-06-302021-03-312020-06-302020-03-31
Value25252526
Percentage of OtherInsuranceRelatedExpenses9.29.89.610.1

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Other
Period End2020-09-302019-09-30
Value2829
Percentage of OtherInsuranceRelatedExpenses11.211.3

us-gaap:OperatingSegments, cna:SpecialtySegment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value7170726673697571
Percentage of OtherInsuranceRelatedExpenses26.227.527.826.328.126.727.627.6

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value0.010.00.00.0-1.00.00.00.0-1.0-1.00.0-1.00.00.00.00.0-1.00.00.0-3.00.00.0
Percentage of OtherInsuranceRelatedExpenses0.03.90.00.0-0.40.00.00.0-0.4-0.40.0-0.40.00.00.00.0-0.40.00.0-1.00.00.0

cna:PaymentstoAcquireMarketableSecuritiesEquity

cna:PaymentstoAcquireMarketableSecuritiesEquity


Paymentsto
Period End2021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value817961922204652523681502998
Percentage of PaymentstoAcquireMarketableSecuritiesEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup us-gaap:StatementBusinessSegments

cna:PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup

cna:CommercialSegment


Pretax
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1.01.0-5.0-4.0-17.035
Percentage of PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup100.0100.0100.0100.0100.0100.0

cna:InternationalSegment


Pretax
Period End2021-06-302020-12-312020-09-302020-06-302019-12-312019-09-30
Value-1.01.00.0-3.07.01.0
Percentage of PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup0.0100.00.060.0-41.22.9

cna:SpecialtySegment


Pretax
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value-10.0-15.0-14.0-16.0-20.0-11.0-34.0-20.0
Percentage of PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup0.00.0-1400.0-1600.0400.0275.0200.0-57.1

us-gaap:CorporateAndOther


Pretax
Period End2021-06-302020-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value4050-10.00.00.00.02.00.00.00.00.00.00.00.0-1.0-1.00.00.0-2.03.0-1.0-12.0-3.04.0-2.0
Percentage of PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup0.0-1000.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

cna:PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup

cna:PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup


Pretax
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
Value29-15.0-12.0-15.022-15.0-44.016-31.0-14.0-21.0-62.0-59.0-39.0-2.0-19.0-8.0251.0-5.0-8.0-14.03.0-5.0-15.09.0-2.03.0-2.0-31.0-58.0-5.08.0139.0-7.0-23.0-25.05.0-36.039-16.0
Percentage of PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup us-gaap:StatementBusinessSegments

cna:CommercialSegment


Pretax
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1.01.0-5.0-4.0-17.035
Percentage of PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup-8.3-6.7-22.726.738.6218.8

cna:InternationalSegment


Pretax
Period End2021-06-302020-12-312020-09-302020-06-302019-12-312019-09-30
Value-1.01.00.0-3.07.01.0
Percentage of PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup-3.4-8.3-0.0-13.6-15.96.2

cna:SpecialtySegment


Pretax
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value-10.0-15.0-14.0-16.0-20.0-11.0-34.0-20.0
Percentage of PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup-34.5100.0116.7106.7-90.973.377.3-125.0

us-gaap:CorporateAndOther


Pretax
Period End2021-06-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value400.00.00.00.00.00.00.0-2.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0-1.00.00.00.02.00.00.0-1.02.01.0-1.0-1.0
Percentage of PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup137.90.0-0.0-0.00.0-0.0-0.0-0.03.2-0.0-0.0-0.0-0.0-0.00.00.0-0.0-0.0-0.00.0-0.0-0.00.050.00.0-0.0-0.0-3.4-0.00.0-7.722.2-14.34.34.0

cna:ProceedsfromSaleofMarketableSecuritiesEquity

cna:ProceedsfromSaleofMarketableSecuritiesEquity


Proceedsfrom
Period End2021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value119804513298435453642044187.0
Percentage of ProceedsfromSaleofMarketableSecuritiesEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:RealizedGainLossonShortTermInvestments

cna:RealizedGainLossonShortTermInvestments


Realized
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value2.00.0-19.0-1.00.01.0-1.0-20.00.03.01.01.04.0
Percentage of RealizedGainLossonShortTermInvestments100.00.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0

cna:ReinsurancePremiumsPaid

cna:ReinsurancePremiumsPaid


Reinsurance
Period End2021-02-05
Value697
Percentage of ReinsurancePremiumsPaid100.0

cna:Retroactivereinsurancebenefitrecognized

cna:Retroactivereinsurancebenefitrecognized


Retroactivereinsurancebenefitrecognized
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value1210.09.020147.01422
Percentage of Retroactivereinsurancebenefitrecognized100.0100.0100.0100.0100.0100.0100.0100.0

cna:RevenuesExcludingInvestmentsAndDerivativesRealizedGainLoss

cna:RevenuesExcludingInvestmentsAndDerivativesRealizedGainLoss


Revenues
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value2991280928652793269725072768267826282664
Percentage of RevenuesExcludingInvestmentsAndDerivativesRealizedGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccretionAmortizationOfDiscountsAndPremiumsInvestments

us-gaap:AccretionAmortizationOfDiscountsAndPremiumsInvestments


Accretion
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
Value172416191715251722252218151510.09.09.01210.07.06.04.0-34.04.0130.0-4.01.0-1.01.04.06.04.010.01210.010.0231710.016213325
Percentage of AccretionAmortizationOfDiscountsAndPremiumsInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerLiabilityRevenueRecognized

us-gaap:ContractWithCustomerLiabilityRevenueRecognized


Contract
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
Value300300274262278286224236246265199200213222
Percentage of ContractWithCustomerLiabilityRevenueRecognized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.0145.04.02248
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded0.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded us-gaap:FinancialInstrument

us-gaap:AssetBackedSecurities


Debt
Period End2020-12-312020-09-302020-06-30
Value0.00.012
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded0.00.054.5

us-gaap:CorporateDebtSecurities


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.0145.04.010.048
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded0.0100.0100.0100.045.5100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-30
Value-2000000.0-7000000.0-7000000.00-20000000.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal100.0100.0100.00.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal us-gaap:FinancialInstrument

us-gaap:AssetBackedSecurities


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-30
Value1000000.0-1000000.04000000.01000000.00
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal-50.014.3-57.10.0-0.0

us-gaap:CorporateDebtSecurities


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-30
Value-3000000.0-6000000.0-11000000.0-1000000.0-20000000.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal150.085.7157.10.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value4000000.02000000.02000000.01000000.01000000.01000000.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease100.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease us-gaap:FinancialInstrument

us-gaap:AssetBackedSecurities


Debt
Period End2021-06-302020-06-30
Value4000000.00
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease100.00.0

us-gaap:CorporateDebtSecurities


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value02000000.02000000.01000000.01000000.01000000.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease0.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.06.07.09.01.05.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold0.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.06.07.09.01.05.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold0.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery


Debt
Period End2020-12-312020-09-302020-06-302020-03-31
Value0001000000.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery0.00.00.0100.0

us-gaap:DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery us-gaap:FinancialInstrument

us-gaap:CorporateDebtSecurities


Debt
Period End2020-12-312020-09-302020-06-302020-03-31
Value0001000000.0
Percentage of DebtSecuritiesAvailableForSaleAllowanceForCreditLossSellBeforeRecovery0.00.00.0100.0

us-gaap:DebtSecuritiesAvailableForSaleRealizedGain

us-gaap:DebtSecuritiesAvailableForSaleRealizedGain


Debt
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
Value51584544102292734283620423769
Percentage of DebtSecuritiesAvailableForSaleRealizedGain100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleRealizedGainLoss

us-gaap:DebtSecuritiesAvailableForSaleRealizedGainLoss


Debt
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value31382617-75.00.03.0-3.0-6.0-28.010.04.018
Percentage of DebtSecuritiesAvailableForSaleRealizedGainLoss100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesAvailableForSaleRealizedLoss

us-gaap:DebtSecuritiesAvailableForSaleRealizedLoss


Debt
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
Value20201318851042731314248323351
Percentage of DebtSecuritiesAvailableForSaleRealizedLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtSecuritiesRealizedGainLoss

us-gaap:DebtSecuritiesRealizedGainLoss


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value3857662769-216.09.07.0-18.031-77.014-1.01231-24.050
Percentage of DebtSecuritiesRealizedGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value-11000000.0-12000000.0-12000000.0-11000000.0-11000000.0-11000000.0-9000000.0-10000000.0-10000000.0-10000000.0-9000000.0-10000000.0-9000000.0-9000000.0-8000000.0-9000000.0-9000000.0-9000000.0-9000000.0-9000000.0-10000000.0
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value393839383939353635363940404038383939394140
Percentage of DefinedBenefitPlanExpectedReturnOnPlanAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanInterestCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanInterestCost

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value161520202020252525252323242326252626282928
Percentage of DefinedBenefitPlanInterestCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value-11.0-11.0-6.0-7.0-7.0-7.0-1.0-1.00.0-1.0-6.0-7.0-6.0-4.0-3.02.0-4.0-2.0-2.0-3.0-2.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1 us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value-1000000.0-1000000.00-1000000.0-1000000.00000-1000000.00-1000000.0-4000000.0-1000000.0-6000000.00-2000000.0000
Percentage of DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1100.0100.00.0100.0100.00.00.00.00.0100.00.0100.0100.0100.0100.00.0100.00.00.00.0

us-gaap:DividendsCommonStockCash us-gaap:StatementEquityComponents

us-gaap:DividendsCommonStockCash

us-gaap:RetainedEarnings


Dividends
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value104309102100102648969595643959682627828267613676968609608686768338545453554041404127272727
Percentage of DividendsCommonStockCash100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EquitySecuritiesFvNiGainLoss us-gaap:FinancialInstrument

us-gaap:EquitySecuritiesFvNiGainLoss

us-gaap:CommonStock


Equity
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
Value9.013254.023-45.0125.04.017-22.0-2.02.01.0
Percentage of EquitySecuritiesFvNiGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PreferredStock


Equity
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
Value152.0412563-133.06.07.01142-50.02.0-10.0-15.0
Percentage of EquitySecuritiesFvNiGainLoss166.715.4164.0625.0273.9295.650.0140.0275.0247.1227.3-100.0-500.0-1500.0

us-gaap:EquitySecuritiesFvNiRealizedGainLoss

us-gaap:EquitySecuritiesFvNiRealizedGainLoss


Equity
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
Value172.0422563-133.06.07.01142-51.02.0-10.0-15.0
Percentage of EquitySecuritiesFvNiRealizedGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss

us-gaap:FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss


Fair
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-30
Value02000000.01000000.00-4000000.0-3000000.0-4000000.0002000000.00-1000000.0-1000000.0-2000000.00000-5000000.0-2000000.0-3000000.01000000.0-1000000.02000000.0-5000000.01000000.05000000.01000000.00
Percentage of FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss0.0100.0100.00.0100.0100.0100.00.00.0100.00.0100.0100.0100.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

us-gaap:FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss us-gaap:FairValueByAssetClass

us-gaap:EquitySecurities


Fair
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-30
Value02000000.01000000.00-4000000.0-3000000.0-4000000.0002000000.001000000.0-1000000.0-2000000.000000-2000000.0000000000
Percentage of FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss0.0100.0100.00.0100.0100.0100.00.00.0100.00.0-100.0100.0100.00.00.00.00.0-0.0100.0-0.00.0-0.00.0-0.00.00.00.00.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1 us-gaap:FairValueByAssetClass, us-gaap:IncomeStatementLocation

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1

us-gaap:CorporateDebtSecurities, cna:NetRealizedInvestmentGainLosses


Fair
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value3.0-13.00.00.00.00.00.00.00.00.00.0-1.0-1.01.00.00.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1100.0100.00.00.00.00.00.00.00.00.00.0100.0100.0100.00.00.0

us-gaap:EquitySecurities, cna:NetRealizedInvestmentGainLosses


Fair
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
Value0.01.00.00.0-4.00.0-4.00.00.02.00.01.0-1.0-2.00.00.00.00.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings10.0-7.70.00.00.00.00.00.00.00.00.00.00.0200.0-0.00.00.00.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1 us-gaap:IncomeStatementLocation

cna:NetRealizedInvestmentGainLosses


Fair
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
Value3.0-12.00.00.0-4.00.0-4.00.00.02.00.0-1.0-1.04.00.01.01.01.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1100.092.30.00.00.00.00.00.00.00.00.00.00.0-400.0-0.0100.00.00.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss


Fair
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value22-51.0151477-46.0-1.0151611-5.00.0-2.0-5.01.02.02.04.0-18.07.04.03.0-2.0-13.00.07.0-12.0-7.05312-21.0-1.09.03.0167.07.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value4.0-9.0-2.09.018-9.00.01.04.03.0-2.00.0-1.0-5.0-1.01.01.02.0-5.0-1.01.00.00.0-12.0-2.010.0-11.0-6.052148.0-21.00.06.04.031-15.04.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss18.217.6-13.364.323.419.6-0.06.725.027.340.00.050.0100.0-100.050.050.050.027.8-14.325.00.0-0.092.30.0142.991.785.798.1116.70.0100.0-0.066.7133.3193.8-214.357.1

us-gaap:CorporateDebtSecurities


Fair
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value16-40.0165.059-37.0-1.014128.0-3.00.0-1.00.01.01.00.01.0-13.07.03.04.0-2.00.0-1.00.0-1.0-1.00.01.00.0-3.02.02.0-4.02.04.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss72.778.4106.735.776.680.4100.093.375.072.760.00.050.0-0.0100.050.00.025.072.2100.075.0133.3100.0-0.00.00.08.314.30.08.3-0.0300.022.266.7-25.028.657.1

us-gaap:USStatesAndPoliticalSubdivisions


Fair
Period End2021-06-302021-03-312020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-09-302012-06-302012-03-31
Value2.0-2.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.01.01.01.01.03.0-3.04.00.01.02.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss9.13.9-0.0-0.00.00.00.0-0.00.0-0.0-0.00.00.00.00.0-0.00.00.00.0-0.0-0.00.00.0-8.3-14.31.98.30.014.3-400.00.014.328.6

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases


Fair
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
Value2187212120639112511017876841224330175213441778139624082561259412827317811977143465203233378411250380490316
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
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
Value8430542035456.0220.02036554130173913381762459.010.05556113781082511731037193270154176291256151263182247
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases38.541.744.69.789.740.211.821.80.026.342.945.195.3100.0100.075.0100.086.4100.079.532.414.525.067.1100.090.483.084.491.997.286.692.265.058.175.975.577.062.360.469.237.178.2

us-gaap:CorporateDebtSecurities


Fair
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
Value12242641294.0674579765648672.00.00.0130.05.00.016945326270.0123.04.0215.0136.013110345068792511330442
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases56.058.352.962.610.359.888.278.297.473.757.154.94.70.00.025.00.011.40.020.567.685.565.032.90.09.63.23.17.72.810.97.89.123.716.721.518.019.210.029.762.013.3

us-gaap:EquitySecurities


Fair
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value3.0120.00.00.00.02.00.00.00.00.00.00.00.00.01.00.00.00.00.04.00.00.00.00.0160.00.01.00.01511470.04.015
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases2.55.80.00.00.00.02.60.00.00.00.00.00.00.00.02.30.00.00.00.010.00.00.00.00.012.50.00.00.50.04.02.718.80.00.84.7

us-gaap:USStatesAndPoliticalSubdivisions


Fair
Period End2021-06-302020-12-312020-09-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312011-12-312011-09-30
Value120.0450.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0130.01.00.00.00.037850.03.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases5.50.021.80.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.013.80.00.40.00.00.025.918.30.00.8

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales


Fair
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value7.03.00.09.00.00.00.00.00.00.00.05.0724.01.046170.00.045169.02190156130.027895906.015316591126180183316296135170
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales100.0100.00.0100.00.00.00.00.00.00.00.0100.0100.0100.0100.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value0.00.09.00.00.00.00.00.00.00.00.0720.00.00.00.00.00.0250.09.020901440.00.026283680.043997211711177254186101117
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales0.00.0100.00.00.00.00.00.00.00.00.0100.00.00.00.00.00.00.055.60.0100.095.2100.092.30.00.094.287.475.60.028.160.079.192.961.742.180.462.874.868.8

us-gaap:CorporateDebtSecurities


Fair
Period End2021-06-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value3.00.00.00.00.00.00.00.00.05.00.04.00.00.01.00.00.020160.01.00.012130.06.04.0206.07317185.02786471073020
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales42.90.00.00.00.00.00.00.00.0100.00.0100.00.00.05.90.00.044.4100.00.04.80.07.7100.00.02.24.222.2100.047.710.319.84.015.047.014.936.122.211.8

us-gaap:EquitySecurities


Fair
Period End2021-06-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value4.00.00.00.00.00.00.00.00.00.00.00.00.01.02.00.00.00.00.00.00.00.00.00.00.00.08.00.00.0151.0151.02.09.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales57.10.00.00.00.00.00.00.00.00.00.00.00.02.211.80.00.00.00.00.00.00.00.00.00.00.08.40.00.08.30.54.70.31.55.3

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements


Fair
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
Value331914179.05.08.07.06.06.029298.08.035241825961532141371455340675611080805065155801649562100146166
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
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
Value10.01710.0145.03.04.04.04.04.027256.06.017137.06.04.09.0145.07.054291423633894282834315859473225384353
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements30.389.571.482.455.660.050.057.166.766.793.186.275.075.048.654.238.924.04.260.043.835.753.876.164.426.457.594.067.985.535.035.068.047.737.473.828.733.740.338.029.531.9

us-gaap:CorporateDebtSecurities


Fair
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
Value222.04.03.04.02.04.03.02.02.02.03.02.02.018111114885.07.03.03.0117.0143.03.05.05.010.08.06.020451113195.0477027
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements66.710.528.617.644.440.050.042.933.333.36.910.325.025.051.445.861.156.091.733.321.921.423.115.515.626.47.54.58.94.512.510.012.030.829.013.87.920.08.147.047.916.3

us-gaap:USStatesAndPoliticalSubdivisions


Fair
Period End2021-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-312011-09-302011-06-302011-03-31
Value1.00.00.00.00.00.00.01.00.00.00.00.00.00.00.01.00.00.00.00.01.09.00.00.00.00.041153.02.04.00.0855.00.08.079
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements3.00.00.00.00.00.00.03.40.00.00.00.00.00.00.06.70.00.00.00.02.217.00.00.00.00.051.218.86.03.12.60.051.88.10.05.547.6

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3


Fair
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
Value2119328.00.00.00.00.0405.00.059135.01.01162428560.03.02.0250.0173710.0421738211730265.0129.0332714369.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3100.0100.0100.0100.00.00.00.00.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3 us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-312012-09-302011-12-312011-09-30
Value219.00.00.00.00.0405.00.029130.00.01012428560.03.02.0210.0170.00.04212210.00.0252.0110.02.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3100.047.40.00.00.00.0100.0100.00.049.2100.00.00.087.1100.0100.0100.00.0100.0100.084.00.0100.00.00.0100.070.655.30.00.083.340.091.70.014.3

us-gaap:CorporateDebtSecurities


Fair
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
Value0.010.02.08.00.00.00.00.00.00.00.0300.05.01.0150.00.00.00.00.00.03.00.00.03710.00.05.03.08.0170.0263.00.09.0332712319.0
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel30.052.66.2100.00.00.00.00.00.00.00.050.80.0100.0100.012.90.00.00.00.00.00.012.00.00.0100.0100.00.029.47.938.1100.00.0100.060.00.0100.0100.0100.085.786.1100.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3


Fair
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
Value5.08.00.02.0141.033163268117325310.0110.0805.039964823620415646277757555169115596642356843662303891
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3 us-gaap:FairValueByAssetClass

us-gaap:AssetBackedSecurities


Fair
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
Value5.08.00.02.0141.033163137108325310.0110.0705.09.09626115531421462056463851418340511491674213733831
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3100.0100.00.0100.0100.0100.0100.0100.096.954.492.3100.0100.0100.0100.00.087.5100.023.1100.054.247.889.234.137.5100.074.172.780.769.1100.059.472.267.877.335.228.688.158.231.7100.034.1

us-gaap:GainLossOnSaleOfDerivatives

us-gaap:GainLossOnSaleOfDerivatives


Gain
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
Value-12.017-3.0-2.0-10.05.02.0-2.0-6.0-5.0-1.01.04.05.0
Percentage of GainLossOnSaleOfDerivatives100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GrossInvestmentIncomeOperating

us-gaap:GrossInvestmentIncomeOperating


Gross
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
Value607521571533549346560503531587350501522505
Percentage of GrossInvestmentIncomeOperating100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GrossInvestmentIncomeOperating us-gaap:FinancialInstrument

cna:OtherInvestmentIncome


Gross
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
Value-1.02.0-1.00.02.00.03.00.00.02.00.01.03.00.0
Percentage of GrossInvestmentIncomeOperating-0.20.4-0.20.00.40.00.50.00.00.30.00.20.60.0

cna:TradingPortfolioSecurities


Gross
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
Value2.05.05.04.08.01.03.02.02.02.01.01.03.02.0
Percentage of GrossInvestmentIncomeOperating0.31.00.90.81.50.30.50.40.40.30.30.20.60.4

us-gaap:EquitySecurities


Gross
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
Value2029411850-44.023161630-14.010.01210.0
Percentage of GrossInvestmentIncomeOperating3.35.67.23.49.1-12.74.13.23.05.1-4.02.02.32.0

us-gaap:FixedIncomeSecurities


Gross
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
Value425428428432430438455452455455456449444446
Percentage of GrossInvestmentIncomeOperating70.082.175.081.178.3126.681.289.985.777.5130.389.685.188.3

us-gaap:LimitedPartner


Gross
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
Value14643836444-70.055123776-115.0234030
Percentage of GrossInvestmentIncomeOperating24.18.314.512.08.0-20.29.82.47.012.9-32.94.67.75.9

us-gaap:Mortgages


Gross
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
Value1514151414141413121214111411
Percentage of GrossInvestmentIncomeOperating2.52.72.62.62.64.02.52.62.32.04.02.22.72.2

us-gaap:ShortTermInvestments


Gross
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.01.01.07.07.08.09.010.08.06.06.06.0
Percentage of GrossInvestmentIncomeOperating0.00.20.22.01.21.61.71.72.31.21.11.2

us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions

us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions


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
Value93-14.0205630-98.037-9.0-25.0-14.0-194.0-151.0132.05.0-47.0-4.0-38.027-35.032-262.0-68.0-175.0-43.091-18.010.057-132.0937960912160-61.069-17.0-188.04.010411139
Percentage of IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInAccruedInvestmentIncomeReceivable

us-gaap:IncreaseDecreaseInAccruedInvestmentIncomeReceivable


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-16.019-22.017-19.08.0-15.011-8.015-14.010.0-18.03.0-27.032-27.026-27.034-26.022-33.042-33.025-37.034-33.036-39.036-30.042-50.036-32.042-25.031-33.044-36.042
Percentage of IncreaseDecreaseInAccruedInvestmentIncomeReceivable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInDeferredPolicyAcquisitionCosts

us-gaap:IncreaseDecreaseInDeferredPolicyAcquisitionCosts


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-20.0327.0-5.01427-11.0-10.01730-18.0-19.01429-10.0-7.01724-16.0-1.02.023-300.0-19.0-5.013-30.0-24.0-11.021-25.0-20.03.040-11.010.02.015-19.01.01215-17.01.0
Percentage of IncreaseDecreaseInDeferredPolicyAcquisitionCosts100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInFinancialInstrumentsUsedInOperatingActivities

us-gaap:IncreaseDecreaseInFinancialInstrumentsUsedInOperatingActivities


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-27.08.07.013-8.0-7.0155.0-7.03.02.0-15.0121.0-1.0-19.05.06.09.0-7.04.03.00.0-16.012-13.00.01.04.0-21.012-9.0-41.04810.0-31.0386.0-9.0-1.015-6.0-28.028
Percentage of IncreaseDecreaseInFinancialInstrumentsUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInInsuranceLiabilities

us-gaap:IncreaseDecreaseInInsuranceLiabilities


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
Value7686052022986715102113414657374-455.0252311-226.0-14.0127135-227.0-202.015551146-256.0147304-141.0-456.01498598-364.011979483-174.02299-232.0-98.04845-242.0-126.0
Percentage of IncreaseDecreaseInInsuranceLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInOtherReceivables

us-gaap:IncreaseDecreaseInOtherReceivables


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-30
Value387700138-315.035722970-342.0179-44.0182-540.0372215-74.0-213.0284-89.0-181.0-229.0223317-12.0-281.054157-120.0-605.0120-126.0272-399.06320299-278.0
Percentage of IncreaseDecreaseInOtherReceivables100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements


Incremental
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-31
Value952000.01020000.0620000.0445000.01015000.01000000.0776000.0971000.0900000.0835000.01009000.0907000.0847000.0974000.0707000.0409000.0542000.0514000.0423000.0654000.0668000.0622000.0660000.0515000.0407000.0372000.0450000.0410000.0339000.0279000.0352000.0272000.0
Percentage of IncrementalCommonSharesAttributableToShareBasedPaymentArrangements100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InvestmentIncomeInvestmentExpense

us-gaap:InvestmentIncomeInvestmentExpense


Investment
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
Value161716161517151616161614161515151514161415141717151417141413161414121413151413151515
Percentage of InvestmentIncomeInvestmentExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilityForFuturePolicyBenefitsPeriodExpense

us-gaap:LiabilityForFuturePolicyBenefitsPeriodExpense


Liability
Period End2020-09-302019-09-30
Value74216
Percentage of LiabilityForFuturePolicyBenefitsPeriodExpense100.0100.0

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1


Liability
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value2328539230018472393284215100388346221914152941986837628023576
Percentage of LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1


Liability
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value8821067931943112412181037102812101309870102811681219965107011471184958102410381147
Percentage of LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1

us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1


Liability
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value1477147013571484161813981367136913101367152612971273125911961426120411731257112312511227
Percentage of LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:LossFromCatastrophes

us-gaap:LossFromCatastrophes


Loss
Period End2020-09-302020-06-30
Value160301
Percentage of LossFromCatastrophes100.0100.0

us-gaap:NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent us-gaap:IncomeStatementLocation, us-gaap:RetirementPlanType

us-gaap:NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent

cna:InsuranceClaimsandPolicyholdersBenefitsIncludingPolicyholdersDividends, us-gaap:PensionPlansDefinedBenefit


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value3.03.014-2.0-2.0-2.02.0-1.0-1.0-1.0-2.0-3.0-2.0-1.0-1.01.0
Percentage of NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherExpense, us-gaap:PensionPlansDefinedBenefit


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value8.08.034-5.0-5.0-5.03.0-1.0-1.0-1.0-4.0-4.0-4.0-3.0-2.01.0
Percentage of NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent266.7266.7242.9250.0250.0250.0150.0100.0100.0100.0200.0133.3200.0300.0200.0100.0

us-gaap:OciBeforeReclassificationsNetOfTaxAttributableToParent

us-gaap:OciBeforeReclassificationsNetOfTaxAttributableToParent


Oci
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value336-594.04072681229-1190.0-95.015433541-152.0-149.0-209.0-412.0-60.07714996-403.052274240
Percentage of OciBeforeReclassificationsNetOfTaxAttributableToParent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OciBeforeReclassificationsNetOfTaxAttributableToParent us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents

us-gaap:Investments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Oci
Period End2021-06-302021-03-312020-06-302020-03-31
Value1.0-3.0-2.0-48.0
Percentage of OciBeforeReclassificationsNetOfTaxAttributableToParent0.30.5-0.24.0

us-gaap:OtherInvestments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Oci
Period End2021-06-302021-03-312020-06-302020-03-31
Value323-593.01209-1066.0
Percentage of OciBeforeReclassificationsNetOfTaxAttributableToParent96.199.898.489.6

us-gaap:OciBeforeReclassificationsNetOfTaxAttributableToParent us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Oci
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-50.0-2.0-2.01.0-88.00.00.0-1.0-32.00.00.00.0-25.00.00.00.0-22.00.00.00.0
Percentage of OciBeforeReclassificationsNetOfTaxAttributableToParent-12.3-0.7-0.2-0.192.60.00.0-0.221.1-0.0-0.0-0.041.70.00.00.05.50.00.00.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Oci
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value2311209-1066.0-42.044434521-83.0-148.0-156.0-414.0-38.03510885-325.069323223
Percentage of OciBeforeReclassificationsNetOfTaxAttributableToParent86.298.489.644.2293.3100.296.354.699.374.6100.563.345.572.588.580.6132.7117.992.9

us-gaap:AccumulatedOtherThanTemporaryImpairment


Oci
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value2.0-2.0-48.0-16.00.0-1.04.05.0-1.0-1.0-10.0-3.01.0-1.00.00.07.0-1.03.0
Percentage of OciBeforeReclassificationsNetOfTaxAttributableToParent0.7-0.24.016.80.0-0.20.7-3.30.70.52.45.01.3-0.70.0-0.013.5-0.41.2

us-gaap:AccumulatedTranslationAdjustment


Oci
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value122.0633724-77.051-29.00.017-42.00.0-52.0126.0414211-56.0-24.0-48.014
Percentage of OciBeforeReclassificationsNetOfTaxAttributableToParent3.6-0.315.513.82.06.5-53.7-193.30.03.127.6-0.024.9-2.9-10.053.228.211.513.9-46.2-17.55.8

us-gaap:OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax

us-gaap:OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value300-627.03692131193-1055.0-59.041436530-55.0-159.0-160.0-438.0
Percentage of OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax us-gaap:FinancialInstrument

cna:InvestmentsWithOtherThanTemporaryImpairments


Other
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value6.02.0-11.0-3.00.00.0-4.025-1.0-1.09.0
Percentage of OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax2.80.21.05.10.00.0-0.8-45.50.60.6-2.1

us-gaap:OtherInvestments


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value300-627.03662071191-1044.0-54.041436526-52.0-158.0-159.0-429.0
Percentage of OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax100.0100.099.297.299.899.091.5100.0100.099.294.599.499.497.9

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value322-616.03922571224-1121.0-88.019444554-121.0-152.0-205.0-416.0-75.07512481-410.027266259-375.0-83.0-278.021-373.0-189.0270250329-13.0-601.0-104.0263103284
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents

us-gaap:OtherInvestments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Other
Period End2021-06-302021-03-312020-06-302020-03-31
Value300-627.01191-1044.0
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent93.2101.897.393.1

us-gaap:OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value10.09.0-40.07.07.011-80.07.08.07.0-24.07.07.010.0-20.010.05.07.0-16.06.05.06.0-67.04.0426.0-160.03.0-51.01.02814.05.05.0
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent3.1-1.5-10.22.70.6-1.090.936.81.81.319.8-4.6-3.4-2.426.713.34.08.63.922.21.92.317.9-4.8-15.128.642.9-1.6-18.90.485.4-30.8-0.8-4.8

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Other
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value2071191-1044.0-54.041436526-52.0-158.0-159.0-429.0-59.0237767-334.042310234-263.0-36.0-365.0112
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent80.597.393.161.4215.898.294.943.0103.977.6103.178.730.762.182.781.5155.6116.590.370.143.4131.3533.3

us-gaap:AccumulatedOtherThanTemporaryImpairment


Other
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value6.02.0-11.0-5.00.00.04.0-3.0-1.0-1.0-9.0-2.01.00.0-4.0-4.03.0-1.05.0-6.02.0-4.0-1.00.01.02.0123.0-3.0-8.014
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent2.30.21.05.70.00.00.72.50.70.52.22.71.30.0-4.91.011.1-0.41.91.6-2.41.4-4.8-0.0-0.50.74.80.923.11.3-13.5

us-gaap:AccumulatedTranslationAdjustment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value122.0633724-77.051-29.00.017-42.00.0-52.0126.0414211-56.0-24.0-48.014-39.0-53.049-96.0-56.0-73.042-8.07.056-13.0-61.0
Percentage of OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent3.7-0.316.114.42.06.9-58.0-152.60.03.134.7-0.025.4-2.9-8.054.733.913.613.7-88.9-18.05.410.463.9-17.6-457.115.038.615.6-3.22.1-430.82.258.7

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value-10.0-9.040-7.0-7.0-11.080-7.0-8.0-7.024-7.0-7.0-10.020-10.0-5.0-7.016-6.0-5.0-6.067-4.0-42.0-6.0160-3.051-1.0-281.0-4.0-5.0-5.0124-3.0-3.0-6.0
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossTaxPortionAttributableToParent1

us-gaap:OtherComprehensiveIncomeLossTaxPortionAttributableToParent1


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value78-160.08760319-281.0-34.013117144-22.0-41.0-45.0-108.0-38.0215141-184.024159122-182.0-18.0-160.065-180.0-87.0124139580-36.0-316.0-25.0
Percentage of OtherComprehensiveIncomeLossTaxPortionAttributableToParent1100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossTaxPortionAttributableToParent1 us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents

us-gaap:OtherInvestments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Other
Period End2021-06-302021-03-312020-06-30
Value75-162.0317
Percentage of OtherComprehensiveIncomeLossTaxPortionAttributableToParent196.2101.299.4

us-gaap:OtherComprehensiveIncomeLossTaxPortionAttributableToParent1 us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value3.02.0-11.03.01.03.0-21.02.02.02.0-7.01.02.03.0-3.05.03.04.0-6.03.03.03.0-36.02.0233.01371.0-28.01.0-166.03.02.03.0
Percentage of OtherComprehensiveIncomeLossTaxPortionAttributableToParent13.8-1.2-12.65.00.3-1.161.815.41.71.431.8-2.4-4.4-2.87.923.85.99.83.312.51.92.519.8-11.1-14.44.6-76.1-1.1-22.60.7-28.6-8.3-0.6-12.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Other
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value56317-281.0-11.011114141-14.0-42.0-46.0-109.0-34.0164838-175.019157116-142.0-21.0-181.062
Percentage of OtherComprehensiveIncomeLossTaxPortionAttributableToParent193.399.4100.032.484.697.497.963.6102.4102.2100.989.576.294.192.795.179.298.795.178.0116.7113.195.4

us-gaap:AccumulatedOtherThanTemporaryImpairment


Other
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value1.01.0-3.0-2.00.01.01.0-1.00.0-1.0-2.0-1.00.00.0-1.0-3.02.0-1.03.0-4.01.0-2.00.0-16.01.01.06.0-5.0-1.0-4.07.0
Percentage of OtherComprehensiveIncomeLossTaxPortionAttributableToParent11.70.31.15.90.00.90.74.5-0.02.21.92.60.00.0-2.41.68.3-0.62.52.2-5.61.20.08.9-1.10.84.3-0.92.81.3-28.0

us-gaap:OtherCostAndExpenseOperating

us-gaap:OtherCostAndExpenseOperating


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value303284274269284299289289281283299302298303437381364346390403378381412362341358410384254346332332320341359341316319260252259277243795258
Percentage of OtherCostAndExpenseOperating100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherExpenses

us-gaap:OtherExpenses


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-31
Value615743505572486457667370976117214114313515014714614614713812112920717241128124121108121118116111111113102112106
Percentage of OtherExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherExpenses us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-1.0-2.0-2.00.0-1.0-2.0-1.0-1.0-1.0-2.0-1.00.00.0-1.00.00.00.00.00.00.00.00.0
Percentage of OtherExpenses-1.6-3.5-4.70.0-1.8-2.8-2.1-1.6-1.8-3.0-1.40.00.0-1.60.00.00.00.00.00.00.00.0

us-gaap:OtherExpenses us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value119.08.07.0126.05.09.0
Percentage of OtherExpenses18.015.818.614.021.88.310.414.1

us-gaap:OperatingSegments, cna:InternationalSegment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value-3.0-5.0-10.0-8.0-2.013-6.07.0
Percentage of OtherExpenses-4.9-8.8-23.3-16.0-3.618.1-12.510.9

us-gaap:OperatingSegments, cna:LifeAndGroupNonCoreSegment


Other
Period End2021-06-302021-03-312020-06-302020-03-31
Value2.02.00.03.0
Percentage of OtherExpenses3.33.50.04.2

us-gaap:OperatingSegments, cna:LifeandGroupSegment


Other
Period End2020-09-302019-09-30
Value3.01.0
Percentage of OtherExpenses6.01.6

us-gaap:OperatingSegments, cna:SpecialtySegment


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1211131410.0131113
Percentage of OtherExpenses19.719.330.228.018.218.122.920.3

us-gaap:OperatingSegments, us-gaap:CorporateAndOther


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value40423334353936353439404467424652504451574754
Percentage of OtherExpenses65.673.776.768.063.654.275.054.759.659.154.862.969.168.926.736.935.032.634.038.832.237.0

us-gaap:OtherOperatingActivitiesCashFlowStatement

us-gaap:OtherOperatingActivitiesCashFlowStatement


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value-71.0-53.04.05257-258.0-46.0-15.0-47.0-117.0
Percentage of OtherOperatingActivitiesCashFlowStatement100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings

us-gaap:OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value-1.06.03.05.0119210.0146.014123.00.06.04.05.02.0
Percentage of OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0

us-gaap:OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings us-gaap:FinancialInstrument

us-gaap:AssetBackedSecurities


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value1.0-1.010.01.0121.01.02.00.08.06.02.00.01.00.01.00.0
Percentage of OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings-100.0-16.7333.320.0109.11.110.014.30.057.150.066.70.016.70.020.00.0

us-gaap:CorporateDebtSecurities


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value-2.07.0-7.04.0-1.0919.0126.06.06.01.00.05.04.04.02.0
Percentage of OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings200.0116.7-233.380.0-9.198.990.085.7100.042.950.033.30.083.3100.080.0100.0

us-gaap:PaymentsForLossesAndLossAdjustmentExpense

us-gaap:PaymentsForLossesAndLossAdjustmentExpense


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value1114115213231243130812901430131214251409125813741389131013801364134512521334130412731223
Percentage of PaymentsForLossesAndLossAdjustmentExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForProceedsFromOtherInvestingActivities

us-gaap:PaymentsForProceedsFromOtherInvestingActivities


Payments
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value5.0-1.01.0-21.01.00.00.0-16.0-2.0-2.01.0-15.00.0-3.0-16.0-1.00.00.0-2.00.0-14.0-7.02.0-2.0-8.0-1.0-6.0-1.0-2.0-3.00.0-6.04.0-3.0-13.0-4.01.0-2.0-1.0-1.00.0-4.0
Percentage of PaymentsForProceedsFromOtherInvestingActivities100.0100.0100.0100.0100.00.00.0100.0100.0100.0100.0100.00.0100.0100.0100.00.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0

us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt

us-gaap:PaymentsToAcquireAvailableForSaleSecuritiesDebt


Payments
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
Value24122203180331103538181816082157244924472541263629182690218820372743209723552598263622381620202631101919190825362849207229922549293627202930220023272842331426542720348037233503
Percentage of PaymentsToAcquireAvailableForSaleSecuritiesDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsToAcquireLimitedPartnershipInterests

us-gaap:PaymentsToAcquireLimitedPartnershipInterests


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value10861805458323128251143930810.062863829183016371696842443453109367360606241109661736
Percentage of PaymentsToAcquireLimitedPartnershipInterests100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsToAcquireMortgageNotesReceivable

us-gaap:PaymentsToAcquireMortgageNotesReceivable


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value0.01618633061105468859
Percentage of PaymentsToAcquireMortgageNotesReceivable0.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PolicyholderDividends

us-gaap:PolicyholderDividends


Policyholder
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
Value7.06.04.05.06.06.04.07.06.06.07.06.06.06.08.05.05.04.0-2.07.04.04.03.02.03.04.04.03.04.03.04.06.06.04.0155.06.03.07.01.04.01.0
Percentage of PolicyholderDividends100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PolicyholderDividends us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, cna:CommercialSegment


Policyholder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value6.05.03.05.05.05.03.05.0
Percentage of PolicyholderDividends85.783.375.0100.083.383.375.071.4

us-gaap:OperatingSegments, cna:SpecialtySegment


Policyholder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value1.01.01.00.01.01.01.02.0
Percentage of PolicyholderDividends14.316.725.00.016.716.725.028.6

us-gaap:PremiumDeficiencyTestingExpenseLongDurationContractAmount

us-gaap:PremiumDeficiencyTestingExpenseLongDurationContractAmount


Premium
Period End2020-09-302019-09-30
Value74216
Percentage of PremiumDeficiencyTestingExpenseLongDurationContractAmount100.0100.0

us-gaap:ProceedsFromLimitedPartnershipInvestments

us-gaap:ProceedsFromLimitedPartnershipInvestments


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value754992245320462120111186392112469326043579076358918716520341550681714195812891846
Percentage of ProceedsFromLimitedPartnershipInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities

us-gaap:ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities


Proceeds
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
Value1020108410541084823799881742798576532532775531100686594782395610167574909947971160114410829471103851775676954866104410898836836216098609654491025
Percentage of ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromPaymentsForOtherFinancingActivities

us-gaap:ProceedsFromPaymentsForOtherFinancingActivities


Proceeds
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-1.0-8.0-1.0-1.00.0-8.0-1.0-1.0-2.0-8.0-1.0-9.08.0-7.0-1.0-16.0-1.00.0-1.02.0-1.00.0-1.0-1.01.05.07.0-1.021-2.0-11.0-6.0-18.0-2.0-4.0-1.0-2.0-1.02.03.0-11.0-2.04.0-1.0
Percentage of ProceedsFromPaymentsForOtherFinancingActivities100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleAndCollectionOfMortgageNotesReceivable

us-gaap:ProceedsFromSaleAndCollectionOfMortgageNotesReceivable


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value2742331610.01534393535451557114.05.0143.0702887224.03.0163.0213.020132.02.0171.01.01.04.01.0
Percentage of ProceedsFromSaleAndCollectionOfMortgageNotesReceivable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleOfAvailableForSaleSecuritiesDebt

us-gaap:ProceedsFromSaleOfAvailableForSaleSecuritiesDebt


Proceeds
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
Value939907881125029508239701014159922591786184122052576127110251783135910941168134417228007311715114490910861369155020391687173414091362145813741929167917882231188132512875
Percentage of ProceedsFromSaleOfAvailableForSaleSecuritiesDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProvisionForLoanLossesExpensed

us-gaap:ProvisionForLoanLossesExpensed


Provision
Period End2020-12-312020-09-302020-06-302020-03-312019-06-302019-03-31
Value5.03.00.0130.00.0
Percentage of ProvisionForLoanLossesExpensed100.0100.00.0100.00.00.0

us-gaap:ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent

us-gaap:ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent


Reclassification
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value142215115.0-69.0-7.0-4.0-11.0-13.0-31.03.0-4.04.0152.025157.0258.0-19.0
Percentage of ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents

us-gaap:Investments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Reclassification
Period End2021-06-302021-03-312020-06-302020-03-31
Value1.0-3.0-4.0-37.0
Percentage of ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent7.1-13.6-80.053.6

us-gaap:OtherInvestments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Reclassification
Period End2021-06-302021-03-312020-06-302020-03-31
Value233418-22.0
Percentage of ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent164.3154.5360.031.9

us-gaap:ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Reclassification
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-10.0-9.0-10.0-9.0-9.0-10.0-8.0-7.0-8.0-8.0-8.0-7.0-7.0-10.0-5.0-10.0-5.0-7.0-6.0-6.0-5.0-6.0
Percentage of ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent-71.4-40.9-66.7-81.8-180.014.5114.3175.072.761.525.8-233.3175.0-250.0-33.3-500.0-20.0-46.7-85.7-24.0-62.531.6

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Reclassification
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value2418-22.0123.0-2.0-5.0-31.010.03.015211231189.02713-11.0
Percentage of ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent218.2360.031.9-171.4-75.018.238.5100.0333.3-75.0375.0140.0600.0124.0120.0128.6108.0162.557.9

us-gaap:AccumulatedOtherThanTemporaryImpairment


Reclassification
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-4.0-4.0-37.0-11.00.0-1.00.08.00.00.0-1.0-1.00.0-1.04.04.04.00.0-2.0
Percentage of ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent-36.4-80.053.6157.1-0.09.1-0.0-25.80.0-0.0-25.0-6.70.0-4.026.757.116.00.010.5

us-gaap:ReclassificationFromAociCurrentPeriodTax

us-gaap:ReclassificationFromAociCurrentPeriodTax


Reclassification
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value4.05.04.04.01.0-19.0-3.0-2.0-2.0-3.0-9.01.0-1.01.0-41.0-1.0117.0-3.0-12.0-3.01118199.03.0
Percentage of ReclassificationFromAociCurrentPeriodTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ReclassificationFromAociCurrentPeriodTax us-gaap:FinancialInstrument, us-gaap:StatementEquityComponents

us-gaap:Investments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Reclassification
Period End2021-06-302021-03-312020-06-302020-03-31
Value0.0-1.0-1.0-10.0
Percentage of ReclassificationFromAociCurrentPeriodTax0.0-20.0-100.052.6

us-gaap:OtherInvestments, us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Reclassification
Period End2021-06-302021-03-312020-06-30
Value7.08.04.0
Percentage of ReclassificationFromAociCurrentPeriodTax175.0160.0400.0

us-gaap:ReclassificationFromAociCurrentPeriodTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Reclassification
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-3.0-2.0-3.0-2.0-2.0-3.0-2.0-2.0-2.0-2.0-2.0-1.0-2.0-3.027-5.0-3.0-4.03.03.03.03.02.02.04.03.0
Percentage of ReclassificationFromAociCurrentPeriodTax-75.0-40.0-75.0-50.0-200.015.866.7100.0100.066.722.2-100.0200.0-300.0-65.9500.0-27.3-57.1-100.0-25.0-100.027.311.110.544.4100.0

us-gaap:AccumulatedNetUnrealizedInvestmentGainLoss


Reclassification
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value7.04.0-6.02.00.00.0-1.0-9.02.01.04.0-66.04.0159.0-4.0-13.0-6.07.08.0175.00.0
Percentage of ReclassificationFromAociCurrentPeriodTax175.0400.031.6-66.7-0.0-0.033.3100.0200.0-100.0400.0161.0-400.0136.4128.6133.3108.3200.063.644.489.555.60.0

us-gaap:AccumulatedOtherThanTemporaryImpairment


Reclassification
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-1.0-1.0-10.0-3.00.00.00.02.00.00.00.0-2.00.0-1.02.0-2.0-2.00.01.08.00.00.00.0
Percentage of ReclassificationFromAociCurrentPeriodTax-25.0-100.052.6100.0-0.0-0.0-0.0-22.20.0-0.00.04.9-0.0-9.128.666.716.7-0.09.144.40.00.00.0

us-gaap:ReinsuranceLossOnUncollectibleAccountsInPeriodAmount

us-gaap:ReinsuranceLossOnUncollectibleAccountsInPeriodAmount


Reinsurance
Period End2021-03-31
Value12
Percentage of ReinsuranceLossOnUncollectibleAccountsInPeriodAmount100.0

us-gaap:ReinsuranceLossOnUncollectibleAccountsInPeriodAmount us-gaap:StatementScenario, us-gaap:SubsequentEventType

srt:ScenarioForecast, us-gaap:SubsequentEvent


Reinsurance
Period End2021-03-31
Value12
Percentage of ReinsuranceLossOnUncollectibleAccountsInPeriodAmount100.0

us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense

us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense


Supplemental
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value1456147413681526154413551388135313061309149213141306124612521506123612071226121613591224
Percentage of SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense

us-gaap:SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense


Supplemental
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value-24.0-54.0-51.0-87.027-8.0-62.0-29.0-44.08.0-6.0-61.0-78.0-34.0-97.0-125.0-77.0-82.0-10.0-134.0-153.0-45.0
Percentage of SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:TreasuryStockValueAcquiredCostMethod

us-gaap:TreasuryStockValueAcquiredCostMethod


Treasury
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value153.00.00.0182.02.014
Percentage of TreasuryStockValueAcquiredCostMethod100.0100.00.00.0100.0100.0100.0100.0

us-gaap:TreasuryStockValueAcquiredCostMethod us-gaap:StatementEquityComponents

us-gaap:TreasuryStock


Treasury
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value153.00.036-36.0185.02.02.0140.00.00.0
Percentage of TreasuryStockValueAcquiredCostMethod100.0100.00.00.00.0100.00.0100.0100.0100.00.00.00.0

us-gaap:UnusualOrInfrequentItemNetOfInsuranceProceeds

us-gaap:UnusualOrInfrequentItemNetOfInsuranceProceeds


Unusual
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value5412516030175323858
Percentage of UnusualOrInfrequentItemNetOfInsuranceProceeds100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnusualOrInfrequentItemNetOfInsuranceProceeds us-gaap:LiabilityForCatastropheClaimsByCatastrophicEvent

cna:COVID19


Unusual
Period End2020-09-302020-06-302020-03-31
Value0.018213
Percentage of UnusualOrInfrequentItemNetOfInsuranceProceeds0.060.517.3

cna:CivilUnrest


Unusual
Period End2020-09-302020-06-30
Value7.061
Percentage of UnusualOrInfrequentItemNetOfInsuranceProceeds4.420.3

cna:WeatherRelatedEvents


Unusual
Period End2020-09-302020-06-302020-03-31
Value1535862
Percentage of UnusualOrInfrequentItemNetOfInsuranceProceeds95.619.382.7

cna:Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves

cna:Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves


Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value15211619172022
Percentage of Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves100.0100.0100.0100.0100.0100.0100.0

cna:Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements

cna:Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements


Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value35364041424243
Percentage of Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements100.0100.0100.0100.0100.0100.0100.0

cna:AnticipatedAmountsDueFromInsuredsRelatedToLossesUnderDeductiblePolicies

cna:AnticipatedAmountsDueFromInsuredsRelatedToLossesUnderDeductiblePolicies


Anticipated
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value12001200120012001200120014001300
Percentage of AnticipatedAmountsDueFromInsuredsRelatedToLossesUnderDeductiblePolicies100.0100.0100.0100.0100.0100.0100.0100.0

cna:CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity

cna:CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity


Carrying
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value2.00.020.020.030.040.030.040.040.040.04
Percentage of CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities

cna:CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities


Carrying
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value30002700250026002300280030003300360035002900
Percentage of CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CarryingValueOfTenLargestLimitedPartnerships

cna:CarryingValueOfTenLargestLimitedPartnerships


Carrying
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value77589387611361168122114921471130912181321
Percentage of CarryingValueOfTenLargestLimitedPartnerships100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CashAndSecuritiesDepositedAsCollateralForLettersOfCredit

cna:CashAndSecuritiesDepositedAsCollateralForLettersOfCredit


Cash
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value1100110010004715143643613534.05.06.0
Percentage of CashAndSecuritiesDepositedAsCollateralForLettersOfCredit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CededClaimAndClaimAdjustmentExpenses

cna:CededClaimAndClaimAdjustmentExpenses


Ceded
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value473547014005395140023967383537023866390040193858415740573934400840804076409442564371439940874344497251265020612255946288
Percentage of CededClaimAndClaimAdjustmentExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CededFuturePolicyBenefits

cna:CededFuturePolicyBenefits


Ceded
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value263226233230212207185733759792822
Percentage of CededFuturePolicyBenefits100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:CollateralTrustAccountPercentageOfOutstandingReserves

cna:CollateralTrustAccountPercentageOfOutstandingReserves


Collateral
Period End2021-06-30
Value105.0
Percentage of CollateralTrustAccountPercentageOfOutstandingReserves100.0

cna:CommitmentsToPurchaseOrFundAdditionalAmounts

cna:CommitmentsToPurchaseOrFundAdditionalAmounts


Commitments
Period End2021-06-302021-03-312020-12-312020-09-30
Value1330136512101170
Percentage of CommitmentsToPurchaseOrFundAdditionalAmounts100.0100.0100.0100.0

cna:CommitmentsToSellVariousPrivatelyPlacedDebtSecurities

cna:CommitmentsToSellVariousPrivatelyPlacedDebtSecurities


Commitments
Period End2021-06-302021-03-312020-12-312020-09-30
Value951008555
Percentage of CommitmentsToSellVariousPrivatelyPlacedDebtSecurities100.0100.0100.0100.0

cna:CumulativeamountscededunderAEPLossPortfolioTransfer us-gaap:ProductOrService

cna:CumulativeamountscededunderAEPLossPortfolioTransfer

cna:AsbestosandEnvironmentalReserves


Cumulativeamountscededunder
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value330033003300320032003200320031003100310031003000300030002900
Percentage of CumulativeamountscededunderAEPLossPortfolioTransfer100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:DebtSecuritiesAmortizedCost

cna:DebtSecuritiesAmortizedCost


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value3982639291389533896938392380343812638258380233794038085
Percentage of DebtSecuritiesAmortizedCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:DeferredTaxAssetsDeferredRetroactiveReinsuranceBenefit

cna:DeferredTaxAssetsDeferredRetroactiveReinsuranceBenefit


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value83827968117846166
Percentage of DeferredTaxAssetsDeferredRetroactiveReinsuranceBenefit100.0100.0100.0100.0100.0100.0100.0100.0

cna:DeferredTaxLiabilitiesDeferredExpenseSoftwareandHardware

cna:DeferredTaxLiabilitiesDeferredExpenseSoftwareandHardware


Deferred
Period End2020-12-312019-12-312018-12-312017-12-31
Value31344446
Percentage of DeferredTaxLiabilitiesDeferredExpenseSoftwareandHardware100.0100.0100.0100.0

cna:Deferredreinsurancebenefityettoberecognized us-gaap:ProductOrService

cna:Deferredreinsurancebenefityettoberecognized

cna:AsbestosandEnvironmentalReserves


Deferredreinsurancebenefityettoberecognizedus-gaap:
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value376388398349358378392331338352374339351366326
Percentage of Deferredreinsurancebenefityettoberecognized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:DiscountedReservesForUnfundedStructureSettlementsDiscountAmount

cna:DiscountedReservesForUnfundedStructureSettlementsDiscountAmount


Discounted
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value65772476079884188092496910001100
Percentage of DiscountedReservesForUnfundedStructureSettlementsDiscountAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:DiscountedReservesForUnfundedStructuredSettlements

cna:DiscountedReservesForUnfundedStructuredSettlements


Discounted
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value520497512527544560582580602632
Percentage of DiscountedReservesForUnfundedStructuredSettlements100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:Discountedreservesforlongtermcareclaimreserves

cna:Discountedreservesforlongtermcareclaimreserves


Discountedreservesforlongtermcareclaimreserves
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value270027002600240022002200
Percentage of Discountedreservesforlongtermcareclaimreserves100.0100.0100.0100.0100.0100.0

cna:Discountedreservesforlongtermcareclaimreservesdiscountamount

cna:Discountedreservesforlongtermcareclaimreservesdiscountamount


Discountedreservesforlongtermcareclaimreservesdiscountamount
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value439462460446529435
Percentage of Discountedreservesforlongtermcareclaimreservesdiscountamount100.0100.0100.0100.0100.0100.0

cna:FairValueOfCollateralTrustAccountEstablishedByNicoUnderAepLossPortfolioTransfer us-gaap:ProductOrService

cna:FairValueOfCollateralTrustAccountEstablishedByNicoUnderAepLossPortfolioTransfer

cna:AsbestosandEnvironmentalReserves


Fair
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value290046004200350033002700370033003100300027003200300029003100
Percentage of FairValueOfCollateralTrustAccountEstablishedByNicoUnderAepLossPortfolioTransfer100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:FutureCapitalCallCommitments us-gaap:RetirementPlanType

cna:FutureCapitalCallCommitments

us-gaap:PensionPlansDefinedBenefit


Future
Period End2020-12-312018-12-312017-12-31
Value19093100
Percentage of FutureCapitalCallCommitments100.0100.0100.0

cna:IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships

cna:IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships


Income
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
Value2.00.020.030.030.040.030.040.040.030.040.030.04
Percentage of IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:IncreaseDecreaseEarnedPremiums

cna:IncreaseDecreaseEarnedPremiums


Increase
Period End2020-12-31
Value-14000000.0
Percentage of IncreaseDecreaseEarnedPremiums100.0

cna:InvestmentInSubsidiaries us-gaap:ConsolidatedEntities

cna:InvestmentInSubsidiaries

srt:ParentCompany


Investment
Period End2020-12-312019-12-312018-12-312017-12-31
Value14996144121342714481
Percentage of InvestmentInSubsidiaries100.0100.0100.0100.0

cna:Liabilityforunpaidclaimandclaimadjustmentexpensegross

cna:Liabilityforunpaidclaimandclaimadjustmentexpensegross


Liabilityforunpaidclaimandclaimadjustmentexpensegross
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value234802305622706225342227021872217202159621729218362198421604219902206722004222092217922260223432267222975230182266323271240892476324303
Percentage of Liabilityforunpaidclaimandclaimadjustmentexpensegross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:Liabilityforunpaidclaimandclaimadjustmentexpensegross us-gaap:StatementBusinessSegments

cna:CommercialSegment


Liabilityforunpaidclaimandclaimadjustmentexpensegrossus-gaap:
Period End2020-12-312019-12-31
Value90418656
Percentage of Liabilityforunpaidclaimandclaimadjustmentexpensegross39.839.9

cna:InternationalSegment


Liabilityforunpaidclaimandclaimadjustmentexpensegrossus-gaap:
Period End2020-12-312019-12-31
Value20911876
Percentage of Liabilityforunpaidclaimandclaimadjustmentexpensegross9.28.6

cna:LifeAndGroupNonCoreSegment


Liabilityforunpaidclaimandclaimadjustmentexpensegrossus-gaap:
Period End2020-12-312019-12-31
Value37433716
Percentage of Liabilityforunpaidclaimandclaimadjustmentexpensegross16.517.1

cna:SpecialtySegment


Liabilityforunpaidclaimandclaimadjustmentexpensegrossus-gaap:
Period End2020-12-312019-12-31
Value57485238
Percentage of Liabilityforunpaidclaimandclaimadjustmentexpensegross25.324.1

us-gaap:CorporateAndOther


Liabilityforunpaidclaimandclaimadjustmentexpensegrossus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value20832234242524362614264429043307
Percentage of Liabilityforunpaidclaimandclaimadjustmentexpensegross9.210.311.011.111.711.712.513.7

cna:LimitedPartnershipEquityRelatedHedgeFundStrategyPlanAssets us-gaap:RetirementPlanType

cna:LimitedPartnershipEquityRelatedHedgeFundStrategyPlanAssets

us-gaap:PensionPlansDefinedBenefit


Limited
Period End2020-12-31
Value69.0
Percentage of LimitedPartnershipEquityRelatedHedgeFundStrategyPlanAssets100.0

cna:LimitedPartnershipHedgeFundMultiStrategyPlanAssets us-gaap:RetirementPlanType

cna:LimitedPartnershipHedgeFundMultiStrategyPlanAssets

us-gaap:PensionPlansDefinedBenefit


Limited
Period End2020-12-31
Value27.0
Percentage of LimitedPartnershipHedgeFundMultiStrategyPlanAssets100.0

cna:LimitedPartnershipHedgeFundStrategyDistressedInvestmentsPlanAssets us-gaap:RetirementPlanType

cna:LimitedPartnershipHedgeFundStrategyDistressedInvestmentsPlanAssets

us-gaap:PensionPlansDefinedBenefit


Limited
Period End2020-12-31
Value4.0
Percentage of LimitedPartnershipHedgeFundStrategyDistressedInvestmentsPlanAssets100.0

cna:LimitedPartnershipInvestments

cna:LimitedPartnershipInvestments


Limited
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
Value178116541619156715581509175217581785187619822297236323642369231123802389237124562542256225482738293029672937293128312799272027902665256424622370224224002245237125542309
Percentage of LimitedPartnershipInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:LimitedPartnershipsInvestedInPrivateDebtAndEquity

cna:LimitedPartnershipsInvestedInPrivateDebtAndEquity


Limited
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-31
Value40.00.330.30.250.270.260.230.220.16
Percentage of LimitedPartnershipsInvestedInPrivateDebtAndEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:MarketableSecuritiesFixedMaturitiesAllowanceForCreditLoss

cna:MarketableSecuritiesFixedMaturitiesAllowanceForCreditLoss


Marketable
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value4543404751490.0
Percentage of MarketableSecuritiesFixedMaturitiesAllowanceForCreditLoss100.0100.0100.0100.0100.0100.00.0

cna:MarketableSecuritiesFixedMaturitiesAtAmortizedCost

cna:MarketableSecuritiesFixedMaturitiesAtAmortizedCost


Marketable
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
Value398263929138953389693839238034381263825838023379403808538052379283799138215388143866838269383613824037838372713725337568371993687537335375103721236913393113912938928385333817037945378853781037345369133679136427
Percentage of MarketableSecuritiesFixedMaturitiesAtAmortizedCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:MortgageLoansonRealEstateCommercialandConsumerAllowanceForCreditLoss

cna:MortgageLoansonRealEstateCommercialandConsumerAllowanceForCreditLoss


Mortgage
Period End2020-09-302020-06-302020-03-312019-12-31
Value2120200.0
Percentage of MortgageLoansonRealEstateCommercialandConsumerAllowanceForCreditLoss100.0100.0100.00.0

cna:NetCaseReserves

cna:NetCaseReserves


Net
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value893091789523964596279836101901017610356101789633
Percentage of NetCaseReserves100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:NetCaseReserves us-gaap:StatementBusinessSegments

cna:CommercialSegment


Net
Period End2020-12-312019-12-31
Value33573543
Percentage of NetCaseReserves37.638.6

cna:InternationalSegment


Net
Period End2020-12-312019-12-31
Value777759
Percentage of NetCaseReserves8.78.3

cna:LifeAndGroupNonCoreSegment


Net
Period End2020-12-312019-12-31
Value32983441
Percentage of NetCaseReserves36.937.5

cna:SpecialtySegment


Net
Period End2020-12-312019-12-31
Value14101343
Percentage of NetCaseReserves15.814.6

us-gaap:CorporateAndOther


Net
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value8892969494130144283292347
Percentage of NetCaseReserves1.01.01.01.01.01.31.42.82.83.4

cna:NetIbnrReserves

cna:NetIbnrReserves


Net
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-31
Value97718707844284258622874087378941928191059741
Percentage of NetIbnrReserves100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

cna:NetIbnrReserves us-gaap:StatementBusinessSegments

cna:CommercialSegment


Net
Period End2020-12-312019-12-31
Value48474306
Percentage of NetIbnrReserves49.649.5

cna:InternationalSegment


Net
Period End2020-12-312019-12-31
Value1045869
Percentage of NetIbnrReserves10.710.0

cna:LifeAndGroupNonCoreSegment


Net
Period End2020-12-312019-12-31
Value317116
Percentage of NetIbnrReserves3.21.3

cna:SpecialtySegment


Net
Period End2020-12-312019-12-31
Value34883333
Percentage of NetIbnrReserves35.738.3

us-gaap:CorporateAndOther


Net
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-31
Value748396111136153171184220244
Percentage of NetIbnrReserves0.81.01.11.31.61.82.02.12.42.7

cna:NonIncomeProducingFixedMaturitySecurities

cna:NonIncomeProducingFixedMaturitySecurities


Non
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value1.01.00.02.00.0540.0
Percentage of NonIncomeProducingFixedMaturitySecurities100.0100.00.0100.00.0100.00.0

cna:OperatingLossCarryforwardsNotSubjectToExpiration

cna:OperatingLossCarryforwardsNotSubjectToExpiration


Operating
Period End2020-12-31
Value46
Percentage of OperatingLossCarryforwardsNotSubjectToExpiration100.0

cna:OperatingLossCarryforwardsSubjecttoExpiration us-gaap:IncomeTaxAuthority

cna:OperatingLossCarryforwardsSubjecttoExpiration

us-gaap:ForeignCountry


Operating