SWN


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

Table of contents



us-gaap:CommonStockValue

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecurities

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareDiluted

us-gaap:AllocatedShareBasedCompensationExpense

us-gaap:ComprehensiveIncomeNetOfTax
us-gaap:ProductOrService
us-gaap:CostOfGoodsAndServicesSold

us-gaap:CostsAndExpenses

us-gaap:GainsLossesOnExtinguishmentOfDebt
us-gaap:LongtermDebtType
us-gaap:StatementBusinessSegments

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments

us-gaap:IncomeTaxExpenseBenefit
us-gaap:StatementBusinessSegments

us-gaap:InterestExpense
us-gaap:StatementBusinessSegments

us-gaap:InterestExpenseDebt

us-gaap:NetIncomeLoss
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic

us-gaap:OperatingIncomeLoss
us-gaap:StatementBusinessSegments

us-gaap:OtherComprehensiveIncomeLossNetOfTax
us-gaap:StatementEquityComponents

us-gaap:OtherNonoperatingIncomeExpense
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:StatementBusinessSegments

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

us-gaap:Revenues

us-gaap:SellingGeneralAndAdministrativeExpense

us-gaap:Assets
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:StockholdersEquity
us-gaap:StatementEquityComponents

us-gaap:AssetsCurrent

us-gaap:Cash

us-gaap:CashAndCashEquivalentsAtCarryingValue
us-gaap:ConsolidationItems
us-gaap:StatementBusinessSegments

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
us-gaap:ConsolidationItems
us-gaap:AccountsReceivableNetCurrent

us-gaap:ReceivablesNetCurrent
us-gaap:StatementBusinessSegments

us-gaap:OtherAssetsCurrent

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:PropertyPlantAndEquipmentNet
us-gaap:ConsolidationItems
us-gaap:StatementBusinessSegments

us-gaap:OperatingLeaseRightOfUseAsset
us-gaap:BusinessAcquisition
us-gaap:ConsolidationItems
us-gaap:StatementBusinessSegments

us-gaap:OtherAssetsNoncurrent

us-gaap:AccountsPayableCurrent

us-gaap:LiabilitiesCurrent

us-gaap:LongTermDebtCurrent
us-gaap:LongtermDebtType

us-gaap:OperatingLeaseLiabilityCurrent

us-gaap:OtherLiabilitiesCurrent

us-gaap:TaxesPayableCurrent

us-gaap:LiabilitiesNoncurrent

us-gaap:LongTermDebt
us-gaap:CreditFacility, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:LongtermDebtType

us-gaap:LongTermDebtNoncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent

us-gaap:OtherLiabilitiesNoncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
us-gaap:PropertyPlantAndEquipmentByType

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree
us-gaap:PropertyPlantAndEquipmentByType

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour
us-gaap:PropertyPlantAndEquipmentByType

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive
us-gaap:PropertyPlantAndEquipmentByType

us-gaap:OperatingLeaseLiability
us-gaap:BusinessAcquisition

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

us-gaap:StockholdersEquity
us-gaap:StatementEquityComponents

us-gaap:CommonStockValue

us-gaap:AdditionalPaidInCapitalCommonStock

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:TreasuryStockValue

us-gaap:StockIssuedDuringPeriodValueNewIssues
us-gaap:StatementEquityComponents

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
us-gaap:StatementEquityComponents

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:AmortizationOfFinancingCosts

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DepreciationDepletionAndAmortization
us-gaap:StatementBusinessSegments

us-gaap:IncreaseDecreaseInAccountsPayable

us-gaap:IncreaseDecreaseInAccountsReceivable

us-gaap:IncreaseDecreaseInInventories

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetIncomeLoss
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome
us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents
us-gaap:StatementEquityComponents

us-gaap:ShareBasedCompensation

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment
us-gaap:StatementBusinessSegments

us-gaap:PaymentsToAcquireProductiveAssets

us-gaap:NetCashProvidedByUsedInFinancingActivities
us-gaap:BusinessAcquisition, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:ProceedsFromIssuanceOfLongTermDebt
us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:EffectiveIncomeTaxRateContinuingOperations

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
us-gaap:AwardType
us-gaap:ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRange

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
us-gaap:AwardType
us-gaap:ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRange
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod

us-gaap:DeferredTaxAssetsValuationAllowance

swn:AllocatedShareBasedCompensationExpenseLiabilityBased
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk
swn:DerivativeAmortizationOfPremiumPaid

swn:DerivativeGainLossOnDerivativeSettledNet
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk

swn:DerivativeGainLossOnDerivativeUnsettledNet
us-gaap:DerivativeInstrumentRisk
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
swn:DerivativePremiumPaid
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk
us-gaap:ReserveQuantitiesByTypeOfReserve
swn:FullCostCeilingTestPriceperBarrel
us-gaap:ReserveQuantitiesByTypeOfReserve
swn:FullCostCeilingTestPriceperMillionBritishThermalUnits

swn:IncreaseDecreaseInAccruedExpendituresBetweenPeriods

swn:LiabilityBasedShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount

swn:ShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeitedInPeriod
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeituresInPeriodWeightedAverageFairValue
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriod
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageFairValue
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriod
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageFairValue

us-gaap:AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation
us-gaap:StatementEquityComponents

us-gaap:AssetImpairmentCharges
us-gaap:PropertyPlantAndEquipmentByType
us-gaap:StatementBusinessSegments

us-gaap:BusinessCombinationAcquisitionRelatedCosts
us-gaap:BusinessAcquisition
us-gaap:StatementBusinessSegments
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual

us-gaap:CurrentIncomeTaxExpenseBenefit
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:DebtInstrumentInterestRateDuringPeriod
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanBenefitObligationIncreaseDecreaseForRemeasurementDueToSettlement

us-gaap:DefinedBenefitPlanContributionsByEmployer
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:RetirementPlanType
us-gaap:DefinedBenefitPlanServiceCost

us-gaap:DerivativeGainLossOnDerivativeNet

us-gaap:EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount

us-gaap:GainLossOnDerivativeInstrumentsNetPretax
us-gaap:StatementBusinessSegments

us-gaap:IncreaseDecreaseInAccruedIncomeTaxesPayable

us-gaap:IncreaseDecreaseInInterestPayableNet

us-gaap:IncreaseDecreaseInOutstandingChecksFinancingActivities
us-gaap:AwardType
us-gaap:IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends
us-gaap:AwardType
us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:InterestCostsCapitalizedAdjustment

us-gaap:InterestExpenseOther

us-gaap:OtherComprehensiveIncomeFinalizationOfPensionAndNonPensionPostretirementPlanValuationTax

us-gaap:OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax

us-gaap:OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax

us-gaap:OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationNetOfTax
us-gaap:StatementEquityComponents

us-gaap:OtherCostAndExpenseOperating

us-gaap:OtherOperatingActivitiesCashFlowStatement

us-gaap:PaymentsForProceedsFromOtherInvestingActivities
us-gaap:RestructuringCostAndReserve
us-gaap:PaymentsForRestructuring

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation

us-gaap:ProceedsFromLongTermLinesOfCredit

us-gaap:ProceedsFromSaleOfPropertyPlantAndEquipment
us-gaap:StatementEquityComponents
us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax

us-gaap:RepaymentsOfLongTermLinesOfCredit

us-gaap:RepaymentsOfOtherLongTermDebt

us-gaap:RestructuringCharges
us-gaap:RestructuringCostAndReserve
us-gaap:RestructuringCostAndReserve, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments
us-gaap:BusinessAcquisition, us-gaap:SubsidiarySaleOfStock
us-gaap:SaleOfStockConsiderationReceivedOnTransaction
us-gaap:RestructuringCostAndReserve
us-gaap:SeveranceCosts1
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice
us-gaap:BusinessAcquisition, us-gaap:StatementEquityComponents
us-gaap:StockIssuedDuringPeriodValueAcquisitions

us-gaap:StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures
us-gaap:StatementEquityComponents

us-gaap:StockIssuedDuringPeriodValueShareBasedCompensationGross
us-gaap:StatementEquityComponents

us-gaap:TaxesExcludingIncomeAndExciseTaxes

us-gaap:UnrealizedGainLossOnDerivatives

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows

srt:ProvedDevelopedAndUndevelopedReserveNetEnergy
us-gaap:StatementGeographical
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:StatementGeographical
srt:ProvedDevelopedAndUndevelopedReservesNet
us-gaap:StatementGeographical
srt:ProvedDevelopedReservesBOE1
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:StatementGeographical
srt:ProvedDevelopedReservesVolume

srt:ProvedUndevelopedReserveBOE1
us-gaap:StatementGeographical
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:StatementGeographical
srt:ProvedUndevelopedReserveVolume

srt:StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves
us-gaap:PropertyPlantAndEquipmentByType, us-gaap:StatementBusinessSegments
swn:AggregateAnnualLeasePayment
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDerivativeAssets
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEvaluatedOilAndGasProperties
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesAssetRetirementObligation
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesRevolvingCreditFacility
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesSeniorNotes
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipmentOther
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProvedOilAndGasProperty
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnevaluatedOilAndGasProperties
us-gaap:BusinessAcquisition
swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnprovedOilAndGasProperty

swn:CapitalizedInterestOfNetUnevaluatedCostsExcludedFromAmortizationCumulative
us-gaap:StatementGeographical

swn:DeferredTaxAssetsFutureOperatingLeasePayments
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
swn:DerivativeBasisDifferentialPerMillionBritishThermalUnit
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
swn:DerivativeBasisDifferentialperMillionBritishThermalUnit
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:HedgingDesignation
swn:DerivativeLiabilityIncreaseDecreaseImpactNonPerformingRisk
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:FinancialInstrumentPerformanceStatus

swn:ExplorationAndDevelopmentCostsCumulative

swn:IncomeTaxAlternativeMinimumTaxRefundSequesteredAmount

swn:LesseeOperatingLeaseNotYetCommenced
us-gaap:AwardType
swn:LiabilityBasedPerformanceUnitsShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized
us-gaap:AwardType
swn:LiabilityBasedRestrictedStockShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized
us-gaap:LongtermDebtType
swn:LongTermDebtCurrentMaturitiesGross

swn:NetBookValueAdjustedForMarketDifferentials

swn:OperatingLossCarryforwardsLimitationOfUse
us-gaap:BusinessAcquisition

swn:OtherCommitmentAssumedByBuyer

swn:OtherCommitmentDueAfterEighthYear
us-gaap:BusinessAcquisition, us-gaap:OtherCommitments
us-gaap:OtherCommitments

swn:OtherCommitmentDueInFifthAndEighthYear
us-gaap:BusinessAcquisition, us-gaap:OtherCommitments
us-gaap:OtherCommitments

swn:OtherCommitmentDueInFirstThroughThirdYear
us-gaap:BusinessAcquisition, us-gaap:OtherCommitments
us-gaap:OtherCommitments

swn:OtherCommitmentDueInLessThanTwelveMonths
us-gaap:BusinessAcquisition, us-gaap:OtherCommitments
us-gaap:OtherCommitments

swn:OtherCommitmentDueInThirdThroughFifthYear
us-gaap:BusinessAcquisition, us-gaap:OtherCommitments
us-gaap:OtherCommitments

swn:OtherCommitmentDueinFifthThroughEighthYear
us-gaap:OtherCommitments

swn:OtherCommitmentLiabilityForEstimatedFuturePayments

swn:OtherCommitmentPotentialAmountToBeReimbursedToBuyer

swn:OtherLiabilitiesMiscellaneousCurrent

swn:OutstandingChecksIncludedInAccountsPayable
us-gaap:StatementBusinessSegments
swn:Prepayments

swn:PresentValueOfProvedReservesDiscountedBasis

swn:ReceivablesFromContractsWithCustomers
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber
us-gaap:AwardType
swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue

swn:TaxCreditCarryforwardsAlternativeMinimumTaxExpectedRefunds

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax

us-gaap:AcquisitionCostsCumulative

us-gaap:AssetRetirementObligation

us-gaap:AssetRetirementObligationCurrent

us-gaap:AssetRetirementObligationsNoncurrent
us-gaap:BusinessAcquisition
us-gaap:BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned
us-gaap:BusinessAcquisition, us-gaap:StatementEquityComponents
dei:LegalEntity, us-gaap:BusinessAcquisition
us-gaap:BusinessAcquisitionPercentageOfVotingInterestsAcquired
us-gaap:BusinessAcquisition
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities
us-gaap:StatementScenario, us-gaap:BusinessAcquisition, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets
us-gaap:BusinessAcquisition
us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet

us-gaap:CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities

us-gaap:CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative
us-gaap:BusinessAcquisition
us-gaap:StatementGeographical

us-gaap:CapitalizedCostsOilAndGasProducingActivitiesGross

us-gaap:CapitalizedCostsOilAndGasProducingActivitiesNet

us-gaap:CapitalizedCostsProvedProperties

us-gaap:CapitalizedCostsUnprovedProperties
us-gaap:FairValueByMeasurementBasis
us-gaap:CashAndCashEquivalentsFairValueDisclosure

us-gaap:ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent

us-gaap:DebtInstrumentCarryingAmount
us-gaap:CreditFacility, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:LongtermDebtType
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:DebtInstrumentRepurchasedFaceAmount

us-gaap:DebtInstrumentUnamortizedDiscount
us-gaap:LongtermDebtType

us-gaap:DebtIssuanceCostsLineOfCreditArrangementsNet

us-gaap:DeferredIncomeTaxLiabilities

us-gaap:DeferredTaxAssetsCapitalLossCarryforwards

us-gaap:DeferredTaxAssetsDerivativeInstruments

us-gaap:DeferredTaxAssetsGross

us-gaap:DeferredTaxAssetsOperatingLossCarryforwards

us-gaap:DeferredTaxAssetsOther

us-gaap:DeferredTaxAssetsPropertyPlantAndEquipment

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeCompensation

us-gaap:DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions

us-gaap:DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations

us-gaap:DeferredTaxLiabilitiesLeasingArrangements

us-gaap:DeferredTaxLiabilitiesOther

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax
us-gaap:ConsolidationItems
us-gaap:DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent
us-gaap:RetirementPlanType, us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanBenefitObligation

us-gaap:DefinedBenefitPlanExpectedAmortizationNextFiscalYear
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:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanFairValueOfPlanAssets
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanFundedStatusOfPlan

us-gaap:DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets
us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateProjectedBenefitObligation
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanType
us-gaap:DefinedBenefitPlanWeightedAverageAssetAllocations

us-gaap:DerivativeAssetsLiabilitiesAtFairValueNet
us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByMeasurementBasis
us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:DerivativeFairValueOfDerivativeAsset
us-gaap:HedgingDesignation
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation, us-gaap:Position
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:DerivativeFloorPrice
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation, us-gaap:Position

us-gaap:DerivativeInstrumentsAndHedges

us-gaap:DerivativeLiabilitiesCurrent

us-gaap:DerivativeLiabilitiesNoncurrent
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:DerivativeNotionalAmount
us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:DerivativeSwapTypeAverageFixedPrice
us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:AwardType
us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
us-gaap:AwardType
us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo

us-gaap:GuaranteeObligationsCurrentCarryingValue
us-gaap:FairValueByMeasurementFrequency, us-gaap:PropertyPlantAndEquipmentByType
us-gaap:ImpairedAssetsToBeDisposedOfByMethodOtherThanSaleCarryingValueOfAsset
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:IntangibleAssetsCurrent

us-gaap:InterestPayableCurrent

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
us-gaap:PropertyPlantAndEquipmentByType

us-gaap:LettersOfCreditOutstandingAmount
us-gaap:CreditFacility, us-gaap:LongtermDebtType
us-gaap:LineOfCredit
us-gaap:CreditFacility, us-gaap:LongtermDebtType
us-gaap:LineOfCreditFacilityCurrentBorrowingCapacity
us-gaap:CreditFacility, us-gaap:FairValueByMeasurementBasis, us-gaap:LongtermDebtType
us-gaap:LinesOfCreditFairValueDisclosure
us-gaap:FairValueByMeasurementBasis

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree

us-gaap:LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo

us-gaap:MoneyMarketFundsAtCarryingValue
us-gaap:FairValueByMeasurementBasis, us-gaap:LongtermDebtType
us-gaap:NotesPayableFairValueDisclosure
us-gaap:BusinessAcquisition
us-gaap:OilAndGasProducingPropertiesOfRateRegulatedCompaniesUnamortizedCost

us-gaap:OilAndGasPropertyFullCostMethodGross

us-gaap:OilAndGasPropertySuccessfulEffortMethodAccumulatedDepreciationDepletionAmortizationAndImpairment
us-gaap:PropertyPlantAndEquipmentByType
us-gaap:OilAndGasPropertySuccessfulEffortMethodGross

us-gaap:OilAndGasPropertySuccessfulEffortMethodNet

us-gaap:OperatingLeaseWeightedAverageDiscountRatePercent
us-gaap:BusinessAcquisition
us-gaap:OperatingLossCarryforwards
us-gaap:IncomeTaxAuthority
us-gaap:StatementBusinessSegments

us-gaap:OtherAssetsMiscellaneousCurrent

us-gaap:OtherAssetsMiscellaneousNoncurrent

us-gaap:OtherCommitment
us-gaap:BusinessAcquisition, us-gaap:OtherCommitments
us-gaap:OtherCommitments
us-gaap:Range, us-gaap:StatementScenario

us-gaap:OtherReceivablesNetCurrent
us-gaap:ConsolidationItems
us-gaap:PrepaidExpenseCurrentAndNoncurrent
us-gaap:StatementBusinessSegments

us-gaap:PropertyPlantAndEquipmentOther

us-gaap:RestructuringReserve
us-gaap:RestructuringCostAndReserve
us-gaap:BusinessAcquisition, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:SeniorLongTermNotes
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
us-gaap:AwardType
us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
us-gaap:AwardType
us-gaap:ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRange

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
us-gaap:AwardType
us-gaap:ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRange
us-gaap:BusinessAcquisition
us-gaap:SharePrice
us-gaap:BusinessAcquisition, us-gaap:StatementEquityComponents
us-gaap:TaxCreditCarryforward
us-gaap:TaxCreditCarryforwardAmount

us-gaap:UnamortizedDebtIssuanceExpense
us-gaap:BalanceSheetLocation, us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:ConsolidationItems
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:LongtermDebtType
us-gaap:StatementBusinessSegments

Plots across concepts


IncomeStatement
Income Loss From Continuing Operations 
Before Income Taxes Minority Interest And Income Loss From Equity Method Investments
Expenses
Other Nonoperating Income Expense
Balance Sheet
Stockholders Equity
Assets
Cash And Cash Equivalents At Carrying Value
Current Assets
Cash And Cash Equivalents At Carrying Value
NonCurrent Assets
Operating Lease Right Of Use Asset
PropertyPlantAndEquipmentNet
Property Plant And Equipment Net
Liabilities
Operating Lease Liability
Current Liabilities
Other Liabilities Current
Noncurrent Liabilities
Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent
Stockholders Equity
Retained Earnings Accumulated Deficit
CashFlow
Net Income Loss
NetCashProvidedByUsedInOperatingActivities
Net Income Loss
NetCashProvidedByUsedInInvestingActivities
Net Cash Provided By Used In Investing Activities
Shares
Weighted Average Number Of Diluted Shares Outstanding
OperatingLeaseLiability
Operating Lease Liability Current
LesseeOperatingLeaseLiabilityPaymentsDue
Lessee Operating Lease Liability Payments Due Year Four

Tables

  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:CommonStockValue ████▆▆▆▆▆▆▆▆▆▆▄▄▄▄▄▄▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁7.07.07.07.06.06.06.06.06.06.06.06.06.06.05.05.05.05.05.05.04.04.04.04.04.04.04.04.04.03.5313.5293.5173.5153.5163.5113.5043.4923.4923.4913.4833.4813.483.477NANANA3.461NANANA
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding ▁█676.722999679.867825NA571.872413541.079192540.308491NA540.038187539.947053541.320487NA581.171753582.878106573.844459NA502.290779498.224599494.494995NA482.48515385.594815382.870847NA382.09808382.114011375.578054NA352.32725352.579522351.985821NA351.22283351.082807350.738309NA348.64963348.162723349.990725NA349.998789349.970819349.697327NA349.228576349.341731349.397997NANANANA
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic █▁676.722999675.385145NA571.872413541.079192540.308491NA539.221101539.005941539.721751NA581.171753581.1592571.297804NA499.812926496.419815493.068NA482.48515385.594815382.870847NA382.09808382.114011375.44403NA351.457043351.391582351.222538NA350.517337350.448806350.03243NA348.64963348.162723348.000074NA347.239793347.13283346.833906NA345.587569345.288773345.099247NANANANA
us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount █▁10.2050747.782382NA9.58381910.7952849.179214NA7.4797857.1297337.270196NA5.4650725.21151515.867213NA81.92033582.37425778.066295NA79.94419383.16300586.809533NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:EarningsPerShareBasic ▆▇▇▆▅▄▇▇▇█▇▇▇▇▇▇▇▇▆▅▅▄▁▂▅▇█▇▇▇▇▇█▇▆▆▅▇▇▇▇▇▇▇▇▇▇▇▇▆-0.90.12-0.14-1.04-1.63-2.860.20.090.261.10.54-0.050.090.360.530.090.450.57-0.48-1.52-1.61-3.03-5.58-4.62-2.130.120.890.60.590.550.410.530.70.36-1.02-0.42-1.40.310.470.50.480.390.430.470.350.50.460.340.35-1.26
us-gaap:EarningsPerShareDiluted ▆▇▇▆▅▄▇▇▇█▇▇▇▇▇▇▇▇▆▅▅▄▁▂▅▇█▇▇▇▇▇█▇▆▆▅▇▇▇▇▇▇▇▇▇▇▇▇▆-0.90.12-0.14-1.04-1.63-2.860.20.090.261.10.54-0.050.090.360.530.090.450.57-0.48-1.52-1.61-3.03-5.58-4.62-2.130.120.880.60.590.550.410.530.70.36-1.02-0.42-1.40.310.450.50.480.390.430.460.350.490.450.340.35-1.26
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
 Operating Margin us-gaap:StatementBusinessSegments swn:ExplorationAndProduction▁█718.0719.0NA308.0223.0353.0NA357.0380.0551.0NA639.0527.0643.0532.0476.0531.0566.0420.0381.0291.0343.0448.0491.0496.0660.0681.0652.0721.0796.0NANANANANANANANANANANANANANANANANANANANA
 Operating Margin us-gaap:StatementBusinessSegments swn:Marketing▁█332.0353.0NA219.0187.0239.0NA279.0287.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
 TTM Greenblatt ROC _ _██▇▆▅▄▇▇▇██▇▇█▇▇▇█▇▆▆▅▂▁▄▇████████▆▇▅▇█████████293.0301.0-244.0-381.0-756.0-1490.064.0-29.022.0213.0352.066.0124.0255.0167.0110.0188.0266.0122.0-725.0-492.0-1100.0-2561.0-2842.0-1284.0165.0285.0286.0367.0434.619317.117309.229325.317251.96-577.304-220.202-787.641185.96263.89295.718282.542232.651256.685270.136206.317288.09266.261NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:AllocatedShareBasedCompensationExpense ▁█9.013.0NA2.06.00.0NA1.04.07.0NA3.05.04.0NA7.06.06.0NA6.014.023.0NA6.06.06.0NA4.04.04.49NA2.9212.9682.994-2.7992.6772.7052.844-1.661.9332.2362.45-1.9062.1792.1362.297NANANANA
us-gaap:ComprehensiveIncomeNetOfTax ▅▇▆▅▄▃▇▇▇█▇▆▇▇▇▇▇▇▆▅▅▄▁▂▄▇▇▇▇▇▇▇▇▇▆▆▅▇▇▇▇▇▇▇▇▇-606.080.0-98.0-592.0-880.0-1547.0108.050.0142.0594.0311.0-25.051.0208.0327.078.0285.0351.0-210.0-706.0-590.0-1128.0-2142.0-1765.0-823.064.0355.0242.0230.0163.56591.39139.179285.4733.318-224.089-274.706-641.167174.274337.211296.54216.395112.07678.48209.241108.797207.299NANANANA
 us-gaap:CostOfGoodsAndServicesSold us-gaap:ProductOrService us-gaap:NaturalGasGatheringTransportationMarketingAndProcessing▅▆▃▂▁▂▄▄▄█▇▄▃▃▂▂333.0356.0271.0226.0201.0248.0298.0288.0293.0441.0421.0288.0265.0255.0236.0236.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:CostsAndExpenses ▂▂▂▂▃▅▂▂▂▂▂▂▂▂▂▂▂▁▁▃▂▄▇█▅▂▂▂▂▂▁▁▁▁▂▂▃▁▁▁▁▁▁▁▁▁757.0771.01023.0908.01166.02082.0681.0665.0645.0777.0823.0885.0692.0665.0642.0627.0623.0580.0562.01376.01014.01679.03248.03591.02048.0768.0677.0642.0668.0678.158589.972559.137536.724481.6891066.691906.051387.369470.509480.26471.537482.624443.684413.746412.036383.626380.027NANANANA
us-gaap:GainsLossesOnExtinguishmentOfDebt NANA0.00.07.028.01.07.00.00.0-9.00.0-8.0NA0.0-59.0-10.0-1.00.0-51.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:GainsLossesOnExtinguishmentOfDebt us-gaap:LongtermDebtType us-gaap:SeniorNotesNANANA0.07.028.0NA7.0NANA-9.0NANANANA-59.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:GainsLossesOnExtinguishmentOfDebt us-gaap:StatementBusinessSegments us-gaap:CorporateAndOtherNANANA0.07.028.0NA7.0NANA-9.00.0-8.0NA0.0-59.0-10.0-1.00.0-51.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments ▁█-609.080.0NA-593.0-880.0-1141.0NA59.0153.0168.0308.0-29.051.0208.0255.063.0284.0351.0-219.0-728.0-594.0-1131.0-2580.0-2827.0-1281.0127.0428.0351.0347.0323.185257.907310.016409.842212.612-304.63-230.57-793.425178.422259.021289.939276.441225.589249.961263.873200.053281.605NANANANA
us-gaap:IncomeTaxExpenseBenefit NANA1.00.00.0406.0-10.010.015.0-426.01.00.00.00.0-79.0-14.0NANA-9.0-20.0-1.01.0-473.0-1088.0-493.049.0116.0140.0140.0128.995113.417124.149164.21185.097-122.777-85.755-305.32570.718100.488114.766108.98788.98100.543103.23578.044109.837NANANANA
 us-gaap:IncomeTaxExpenseBenefit us-gaap:StatementBusinessSegments swn:ExplorationAndProductionNANANA0.00.0406.0NA10.015.0-426.0NANANANA-79.0-14.0NANA-9.0-20.0-1.01.0-549.0-1112.0-630.018.093.0107.0105.098.0NANANANANANANANANANANANANANANANANANANANA
us-gaap:InterestExpense ▅▅▅▄▄▄▄▃▃▃▄▅▅▆▆▅▆▅▅▅▃▃▂▁▁█▄▃▃▃▃▃▂▂▂▂▂▂▂▂▂▂▂▂▂▂30.031.031.022.022.019.019.017.015.014.024.029.032.039.038.031.034.032.031.026.017.014.04.00.01.051.020.013.012.012.90712.27711.0189.2789.0219.35210.6068.3617.3384.8125.6576.177.4366.8866.5896.186.508NANANANA
us-gaap:InterestExpenseDebt ▆▆▆▅▅▅▅▅▅▅▆▇▇██▇▇▇▇▇▇▆▆▆▆▆▃▃▃▃▃▃▃▂▂▃▂▂▁▁▁▁▁▁▁▁48.050.048.043.040.040.041.042.041.042.051.056.059.065.064.058.059.058.058.059.056.053.047.051.052.050.026.025.025.025.22925.4725.43525.04924.09724.14225.46323.95619.73517.04116.69616.6415.04414.44214.57414.19913.929NANANANA
us-gaap:NetIncomeLoss ▅▇▆▅▄▂▇▇▇█▇▆▇▇▇▇▇▇▆▅▅▄▁▂▄▇▇▇▇▇▇▇▇▇-609.080.0-92.0-593.0-880.0-1547.0110.049.0138.0594.0307.0-29.051.0208.0334.077.0284.0351.0-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078.0312.0211.0207.0194.0144.0186.0246.0128.0NANANANA158.533175.173167.454136.609149.511160.741122.069171.797157.826118.254121.1-432.83
 us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeNANA4.01.0NANA-13.01.04.00.06.0NANANA0.01.0NANANANANANA-41.0-29.0-33.0-25.029.0-27.95926.39-26.431NANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome,us-gaap:StatementEquityComponents us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome,us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditNANANA1.0NANANA1.04.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents us-gaap:RetainedEarnings▁█-609.080.0NA-593.0-880.0-1547.0NA49.0138.0594.0307.0-29.051.0208.0334.077.0284.0351.0-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078.0312.0211.0NANANANANANANANANANANANANANANANANANANANANANA
us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic NANA-92.0-593.0-880.0-1547.0110.049.0138.0594.0307.0-29.051.0205.0267.043.0224.0281.0-237.0-735.0-620.0-1159.0-2134.0-1766.0-815.046.0312.0211.0207.0194.0NANANANANANANANANANANANANANANANANANANANA
us-gaap:OperatingIncomeLoss ██▇▆▅▄▇▇▇██▇▇█▇▇▇█▇▆▆▅▂▁▄▇████████▆▇▅▇█████████▇█▆293.0301.0-244.0-381.0-756.0-1490.064.0-29.022.0213.0352.066.0124.0255.0167.0110.0188.0266.0122.0-725.0-492.0-1100.0-2561.0-2842.0-1284.0165.0285.0286.0367.0434.619317.117309.229325.317251.96-577.304-220.202-787.641185.96263.89295.718282.542232.651256.685270.136206.317288.09266.261197.038202.227-700.492
us-gaap:OtherComprehensiveIncomeLossNetOfTax NANANA1.00.0NANA1.04.00.04.04.00.00.0-7.01.01.0NA0.02.03.04.0-35.0-26.0-35.0-14.043.031.022.625-30.625-53.1-46.68839.839-94.197-42.236-129.891NANANANANANANANANANANANANANA
 us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNANANA1.00.00.0NA1.04.00.04.0NANANA-13.01.0NANA0.02.03.01.0-2.0NANANANANANA0.08111.9530.2660.2670.267NANANANANANANANANANANANANANANANA
 us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents us-gaap:AccumulatedOtherComprehensiveIncomeNANANA1.00.00.0NA1.04.00.04.04.0NANA-7.01.01.0NA0.02.03.04.0-35.0-26.0-35.0-14.043.031.022.625-30.625-53.1-46.68839.839-94.197-42.236-129.891NANANANANANANANANANANANANANA
us-gaap:OtherNonoperatingIncomeExpense ▄▅▃▆▄▅▄▃▁▅▄▄▆▄▄▃█▆-1.01.0-2.02.00.01.00.0-2.0-6.01.0-1.0-1.03.0-1.0-1.0-2.06.02.0NA3.00.0-3.0-32.00.03.0-1.0-5.00.0-0.1931.1932.705-0.3190.354-0.533-1.5850.2382.577-0.2-0.057-0.1220.0690.3740.1620.326-0.0840.023NANANANA
 us-gaap:OtherNonoperatingIncomeExpense us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome,us-gaap:StatementEquityComponents us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome,us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditNANANA2.0NANANA2.05.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:OtherNonoperatingIncomeExpense us-gaap:StatementBusinessSegments swn:ExplorationAndProduction▁█-1.01.0NA2.0-1.01.0NA-4.0-5.01.0NA0.03.00.0-1.01.02.02.02.02.03.0-2.0-23.00.03.0-1.0-4.00.0-1.02.0NANANANANANANANANANANANANANANANANANANANA
 us-gaap:OtherNonoperatingIncomeExpense us-gaap:StatementBusinessSegments us-gaap:CorporateAndOtherNANANA0.01.00.0NA2.0-1.00.0NA0.00.00.0NANANA-1.0-1.00.0-1.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax ▇▇▄▂▁▃▄▃▃▆█▆▅▆▅▄▅▅▄▃▂▃▄▄▄▆▆▆▇▇▆▅▅▄▄▄▃▃▄▄▄▃▃▃▃▃▃▂▂▂1050.01072.0779.0527.0410.0592.0745.0636.0667.0990.01175.0951.0816.0920.0809.0737.0811.0846.0684.0651.0522.0579.0687.0749.0764.0933.0962.0928.01035.01112.777907.089868.366862.041733.649772.998685.848599.728656.469744.15767.255765.166676.335670.431682.172589.943668.117624.493502.949477.52540.817
us-gaap:Revenues ▇▇▄▂▁▃▄▃▃▆█▆▅▆▅▄▅▅▄▃▂▃▄▄▄▆▆▆▇▇▆▅▅▄▄▄▃▃▄▄▄▃▃▃▃▃▃▂▂▂1050.01072.0779.0527.0410.0592.0745.0636.0667.0990.01175.0951.0816.0920.0809.0737.0811.0846.0684.0651.0522.0579.0687.0749.0764.0933.0962.0928.01035.01112.777907.089868.366862.041733.649772.998685.848599.728656.469744.15767.255765.166676.335670.431682.172589.943668.117624.493502.949477.52540.817
us-gaap:SellingGeneralAndAdministrativeExpense ▂▃▂▂▂▁▄▃▃▃▄▄▆▅▆▆▅▄█▆▅▅▅▆▆▇▆▅▅▅▅▄▄▃▄▂▄▄▄▂▃▃▃▂▂▂34.038.032.031.032.026.047.042.040.037.044.051.059.055.063.062.058.050.076.061.056.054.058.060.060.068.059.054.052.056.38755.55650.96947.5737.21545.26836.12144.93248.82645.08635.640.23837.11740.82835.15836.63332.944NANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:Assets ▂▂▂▁▁▂▃▂▂▂▂▃▃▃▃▃▃▃▃▃▃▄▃▅▇██▄▄▄▃▃▃▃▃▃▃▄▃▃▃▂▂▂▂5394.05247.05160.04157.04555.05275.06717.06598.06545.06446.05797.07058.07042.07713.07521.07202.07150.07196.07076.06890.07377.08518.08110.010725.013504.015587.014925.09177.08887.08423.1648047.7267894.3887635.1916916.7916737.5277072.9517503.9638554.1617902.8977214.1076742.1016340.7486017.4635992.7245590.351NA4770.25NANANA
us-gaap:LiabilitiesAndStockholdersEquity ▂▂▂▁▁▂▃▂▂▂▂▃▃▃▃▃▃▃▃▃▃▄▃▅▇██▄▄▄▃▃▃▃▃▃▃▄▃▃▃▂▂5394.05247.05160.04157.04555.05275.06717.06598.06545.06446.05797.07058.07042.07713.07521.07202.07150.07196.07076.06890.07377.08518.08110.010725.013504.015587.014925.09177.08887.08423.1648047.7267894.3887635.1916916.7916737.5277072.9517503.9638554.1617902.8977214.1076742.1016340.7486017.463NANANA4770.25NANANA
us-gaap:StockholdersEquity ▁▂▂▁▂▃▄▄▄▄▃▃▃▃▃▃▃▂▂▂▂▂▃▅▇█▆▅▅-18.0586.0497.0384.0823.01701.03246.03135.03082.02937.02362.02205.02250.02193.01979.01652.01573.01278.0917.01123.0573.01148.02282.04437.06218.07057.04662.04293.04042.0NA3622.0NANANA3036.0NANANA3969.0NANANA2964.876NANANA2331.225NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AccumulatedDefinedBenefitPlansAdjustment▄▁▁▇▆▆▆█▇▃▃-21.0-24.0-24.0-18.0-19.0-19.0-19.0-17.0-18.0-22.0-22.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AccumulatedOtherComprehensiveIncome▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▂▂▂▂▂▁▁▁▃▅▇█▅▃-35.0-38.0-38.0-32.0-33.0-33.0-33.0-31.0-32.0-36.0-36.0-40.0-44.0-44.0-44.0-37.0-38.0-39.0-39.0-39.0-41.0-44.0-48.0-13.013.048.062.019.0-12.0NA-4.0NANANA150.0NANANA408.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapital████▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▅▅▅▅▅▅▁▁▁5104.05102.05093.04882.04730.04728.04726.04723.04720.04717.04715.04714.04709.04703.04698.04698.04697.04687.04677.04673.03418.03403.03409.03396.03384.03372.01019.01005.0996.0NA969.0NANANA934.0NANANA903.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:CommonStock████▆▆▆▆▆▆▆▆▆▆▃▃▃▃▃▃▁▁▁▁▁▁▁▁▁7.07.07.07.06.06.06.06.06.06.06.06.06.06.05.05.05.05.05.05.04.04.04.04.04.04.04.04.04.0NA4.0NANANA4.0NANANA4.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:RetainedEarnings▁▂▁▂▂▃▄▄▄▄▃▃▃▃▃▃▂▂▂▂▃▃▄▆▇████-4892.0-4283.0-4363.0-4271.0-3678.0-2798.0-1251.0-1361.0-1410.0-1548.0-2142.0-2449.0-2420.0-2471.0-2679.0-3013.0-3090.0-3374.0-3725.0-3515.0-2807.0-2214.0-1082.01051.02818.03633.03577.03265.03054.0NA2653.0NANANA1949.0NANANA2656.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:TreasuryStock▁▁▁▁▁▁▁▁▁▁▂▇█████████████-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-181.0-26.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0NANANANANANANANANA-1.0NANANA-2.0NANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:AssetsCurrent ▂▂▂▂▃▄▂▂▃▃▄▂▂▆▆▆▇███▅█▁▂▂▃▄▂▂▂▂▃▃▂▃▃▄▅▄▃▂▂▂593.0602.0671.0613.0770.0972.0679.0633.0764.0887.0956.0615.0567.01488.01509.01476.01579.01789.01872.01889.01278.01884.0393.0570.0699.0888.01115.0660.0662.0683.101644.175739.975792.833616.807808.912846.7471003.5131228.407978.278836.12686.142557.145580.893NANANA564.501NANANA
us-gaap:Cash ▁▁▁▃▁▁▁▁▃▃▂▁▁██████▂▁▂▁2.04.013.093.07.05.05.09.071.089.032.08.020.0267.0261.0259.0263.0265.0254.031.012.057.015.0NANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:CashAndCashEquivalentsAtCarryingValue ▁▁▁▁▁▁▁▁▂▃▂▁▁▅▅▅▆▇▇▇▅█▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▂▁▁▁▁▁▁▁▁▁2.04.013.095.010.05.05.029.0155.0366.0201.09.037.0958.0916.0989.01111.01382.01423.01474.0998.01597.015.015.037.017.053.020.020.018.71922.93818.9525.68517.50853.58318.5641.499206.16715.62713.29313.27917.38716.05514.19713.94813.913.184NANANA
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents ▁▁▁▂▁▁▁▁▂▄▂▁▁██2.04.013.095.010.05.05.029.0155.0366.0201.09.037.0958.0916.0NANANA1423.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:AccountsReceivableNetCurrent us-gaap:ConsolidationItems swn:CorporateAndReconcilingItemsNANA1.0NANANANANANANA4.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:ReceivablesNetCurrent ▅▄▄▁▂▂▃▃▄▄█▄▅▄▅▄▃▃▄▂▁▁▃▄▄▆▇▆▇▇▆▅▅▄▄▂▂▂▃▃▃▃▄408.0400.0368.0239.0250.0292.0345.0323.0358.0390.0581.0397.0416.0382.0428.0360.0351.0310.0363.0274.0235.0224.0327.0355.0386.0491.0530.0457.0513.0542.037464.045444.723445.936387.324377.638297.773272.75299.316341.915346.896336.717339.59351.573NANANA263.076NANANA
us-gaap:OtherAssetsCurrent NANA49.0NANANA51.0281.0251.0131.044.041.043.038.035.036.034.039.035.048.029.028.045.055.057.046.0158.029.051.072.05548.57635.4336.65741.44758.31571.84966.8964.8960.03744.59234.48838.37947.755NANANA95.163NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment █████▇▇▇▇▇▇▇▇▇▇▇▇▇▇▆▆▆▆▅▄▃▃▃▃▃▃▂▂▂▂▂▂▁▁▁▁▁▁23846.023741.023673.023247.022825.022095.020503.020383.020279.020162.020049.019928.020276.020136.019997.019904.019767.019641.019534.019501.018582.018002.016821.014038.010934.09144.08845.08652.08462.08225.3948005.8367786.827574.1337380.237191.4636414.9555763.8824617.8824415.3394230.1214042.7583861.0533682.688NANANA3054.531NANANA
us-gaap:PropertyPlantAndEquipmentNet ▂▂▂▁▁▁▂▂▂▂▂▂▃▃▃▂▂▂▂▂▃▃▄▅▇██▄▄▄▄▃▃▃▃▃▃▃▃▃▃▃▂4446.04284.04111.03222.03426.03916.05267.05199.05099.04871.04656.05469.06233.05968.05772.05550.05341.05143.04955.04789.05947.06491.07543.09979.012615.014483.013712.08393.08089.07602.6737296.6237036.7336694.2566181.5085836.9766091.9486289.57026.0726645.486214.2725931.0665655.9355298.197NANANA4127.253NANANA
us-gaap:OperatingLeaseRightOfUseAsset ▆▇█▆▇▇▇█▁▁147.0155.0163.0145.0153.0152.0159.0164.0103.0100.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherAssetsNoncurrent ▄▄▄▃▄▄██▇▇▂▂▃▃▃▂▂▃▃▂▂▂▂▂▂▂▁▁▁▁▁▁▂▁▁▁▂▃▃▂▁▁▁355.0361.0378.0322.0359.0387.0771.0766.0682.0688.0185.0194.0242.0257.0240.0176.0230.0264.0249.0212.0152.0143.0174.0176.0190.0216.098.0124.0136.0137.39106.928117.68148.102118.47691.639134.256210.95299.682279.139163.715124.893127.668138.373NANANA78.496NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:AccountsPayableCurrent ▇▇▆▃▃▄▅▅▆▇▇▆▇▆▅▅▄▃▄▃▁▂▅▇▆▇▇██▇▅▆▆▆▄▄▄▅▅▄▅▄▄653.0639.0573.0416.0426.0465.0525.0539.0585.0626.0609.0563.0642.0555.0533.0502.0473.0436.0473.0423.0296.0346.0513.0615.0578.0606.0653.0690.0688.0642.744507.468601.414574.713553.147459.569468.646484.146512.017514.071487.186536.213487.249473.89NANANA404.695NANANA
us-gaap:LiabilitiesCurrent ▃▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▂▂▁▁▁▁▁▂▂█▂▂▂▁▁▂▁▁▁▂▂▂▁▁▁▁1944.01370.01012.0869.0875.0914.0848.0880.0912.0943.0846.0892.0858.0732.0780.0784.0821.01121.01064.0649.0591.0478.0707.0782.0840.0945.05428.0888.0886.0835.155688.011809.811847.055731.474767.771761.165885.949960.644884.913766.25767.349695.191693.983NANANA536.416NANANA
us-gaap:LongTermDebtCurrent ▄▄207.0207.0NANANANANA52.052.052.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OperatingLeaseLiabilityCurrent ▇▇█▂▂▁▂41.041.042.033.034.032.034.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:OtherLiabilitiesCurrent NANA20.0NANANA54.0289.0327.0317.048.010.024.023.024.042.023.033.035.020.055.012.024.028.037.0108.030.047.026.0123.14654.68666.69362.44441.89635.74914.68521.9517.4617.68317.17414.35415.21415.409NANANA12.788NANANA
us-gaap:TaxesPayableCurrent ▅▅▆▃▃▄▄▄▄▅▄▁▄▃▅▄▅▃▄▃▅▄▅▃▅▆█▅▅▄▅▃▇▃▅▂▅▃▂▁▂▂▃62.067.074.047.048.052.059.055.052.062.058.032.058.050.062.055.064.050.059.047.061.052.064.049.062.072.092.069.066.055.15668.01948.26380.5748.80362.9836.90261.45348.97640.69128.88737.71136.40650.051NANANA25.5NANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:LiabilitiesNoncurrent ▃▃▄▃▃▃▃▂▂▂▂▄▄▅▅▅▅▅▅▅▆▇▅▆▇█▅▄▄▄▄▄▃▃▃▃▃▂▁▁▁▁▁3468.03291.03651.02904.02857.02660.02623.02583.02551.02566.02589.03961.03934.04788.04762.04766.04756.04797.05095.05118.06213.06892.05121.05506.06446.07585.04835.03996.03959.03787.5693737.6853564.5883414.5413103.5092933.8843058.5073102.1371772.3781706.581568.3041452.9211357.3641265.604NANANA895.353NANANA
us-gaap:LongTermDebt ▇▇█▃▃▁▁▁▂▂▂3020.03019.03150.02450.02440.02279.02242.02271.02319.02319.02318.0NANANA4391.04436.04381.04630.04653.04652.05768.06443.04705.0NANANANANA1838.01827.4261950.0961911.1651897.7341703.4031668.2731696.5421670.0111670.581343.31272.21216.61204.11094.2NANANA998.7NANANA
us-gaap:LongTermDebtNoncurrent ▃▃▃▂▂▂▂▂▂▂▂▄▄▅▅▅▅▅▅▅▇█▅▅▅▆▂▁2814.02812.03150.02450.02440.02279.02242.02219.02267.02267.02318.03572.03570.04393.04391.04396.04341.04364.04612.04651.05767.06442.04728.04663.04539.05163.02466.01806.0NANA1950.0NANANANA1695.3421668.8111669.381342.11271.01215.41202.91093.0NANANA997.5NANANA
us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent ▄▅▆▄▅▅▆▅▅▆▆▇███▆▆▆▇▇▇▇▇▆▆▆▆▂▂▁▁▄▄▄▄▂▁▂▂▁▁▂▁33.040.045.035.037.040.043.039.039.043.046.050.055.058.058.046.046.047.049.051.051.050.050.048.046.045.044.017.017.016.41315.82334.96334.36933.77333.17418.14116.71620.28420.33813.62914.98218.32415.777NANANA12.63NANANA
us-gaap:OtherLiabilitiesNoncurrent ▃▃▃▂▅▄▄▆▄▅▄▃▆▆▆▆▇▇██▇▇▆▆▆▇▇▅▅▄▄▄▄▄▃▂▁▁▁▁▁▁▁162.0160.0156.0124.0267.0227.0219.0325.0245.0256.0225.0162.0309.0337.0313.0324.0369.0386.0434.0416.0395.0398.0343.0347.0339.0368.0374.0260.0272.0249.534239.437229.627221.892235.021183.299141.32194.6391.67499.38988.88881.15375.05579.347NANANA67.764NANANA
us-gaap:OperatingLeaseLiabilityNoncurrent ▁▄▇▂▅▆█104.0111.0117.0107.0113.0114.0119.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo NANA37.0NANANA33.040.042.032.028.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo us-gaap:PropertyPlantAndEquipmentByType swn:CompressionRentalsNANA14.0NANANA13.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo us-gaap:PropertyPlantAndEquipmentByType swn:OfficeSpaceVehiclesAndEquipmentNANA21.0NANANA24.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree NANA26.0NANANA22.031.019.018.014.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree us-gaap:PropertyPlantAndEquipmentByType swn:CompressionRentalsNANA3.0NANANA9.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour NANA18.0NANANA19.021.010.09.06.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour us-gaap:PropertyPlantAndEquipmentByType swn:CompressionRentalsNANA1.0NANANA2.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour us-gaap:PropertyPlantAndEquipmentByType swn:OfficeSpaceVehiclesAndEquipmentNANA14.0NANANA16.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive NANA14.0NANANA15.019.08.08.05.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive NANA42.0NANANA52.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive us-gaap:PropertyPlantAndEquipmentByType swn:OfficeSpaceVehiclesAndEquipmentNANA36.0NANANA45.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:StockholdersEquity ▁▂▂▁▂▃▄▄▄▄▃▃▃▃▃▃▃▂▂▂▂▂▃▅▇█▆▅▅-18.0586.0497.0384.0823.01701.03246.03135.03082.02937.02362.02205.02250.02193.01979.01652.01573.01278.0917.01123.0573.01148.02282.04437.06218.07057.04662.04293.04042.0NA3622.0NANANA3036.0NANANA3969.0NANANA2964.876NANANA2331.225NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AccumulatedDefinedBenefitPlansAdjustment▄▁▁▇▆▆▆█▇▃▃-21.0-24.0-24.0-18.0-19.0-19.0-19.0-17.0-18.0-22.0-22.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AccumulatedOtherComprehensiveIncome▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▂▂▂▂▂▁▁▁▃▅▇█▅▃-35.0-38.0-38.0-32.0-33.0-33.0-33.0-31.0-32.0-36.0-36.0-40.0-44.0-44.0-44.0-37.0-38.0-39.0-39.0-39.0-41.0-44.0-48.0-13.013.048.062.019.0-12.0NA-4.0NANANA150.0NANANA408.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapital████▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▅▅▅▅▅▅▁▁▁5104.05102.05093.04882.04730.04728.04726.04723.04720.04717.04715.04714.04709.04703.04698.04698.04697.04687.04677.04673.03418.03403.03409.03396.03384.03372.01019.01005.0996.0NA969.0NANANA934.0NANANA903.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:CommonStock████▆▆▆▆▆▆▆▆▆▆▃▃▃▃▃▃▁▁▁▁▁▁▁▁▁7.07.07.07.06.06.06.06.06.06.06.06.06.06.05.05.05.05.05.05.04.04.04.04.04.04.04.04.04.0NA4.0NANANA4.0NANANA4.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:RetainedEarnings▁▂▁▂▂▃▄▄▄▄▃▃▃▃▃▃▂▂▂▂▃▃▄▆▇████-4892.0-4283.0-4363.0-4271.0-3678.0-2798.0-1251.0-1361.0-1410.0-1548.0-2142.0-2449.0-2420.0-2471.0-2679.0-3013.0-3090.0-3374.0-3725.0-3515.0-2807.0-2214.0-1082.01051.02818.03633.03577.03265.03054.0NA2653.0NANANA1949.0NANANA2656.0NANANANANANANANANANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:TreasuryStock▁▁▁▁▁▁▁▁▁▁▂▇█████████████-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-181.0-26.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0NANANANANANANANANA-1.0NANANA-2.0NANANANANANANANANANANA
us-gaap:CommonStockValue ████▆▆▆▆▆▆▆▆▆▆▄▄▄▄▄▄▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁7.07.07.07.06.06.06.06.06.06.06.06.06.06.05.05.05.05.05.05.04.04.04.04.04.04.04.04.04.03.5313.5293.5173.5153.5163.5113.5043.4923.4923.4913.4833.4813.483.477NANANA3.461NANANA
us-gaap:AdditionalPaidInCapitalCommonStock ████▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▅▅▅▅▅▅▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁5104.05102.05093.04882.04730.04728.04726.04723.04720.04717.04715.04714.04709.04703.04698.04698.04697.04687.04677.04673.03418.03403.03409.03396.03384.03372.01019.01005.0996.0985.396970.524960.058952.838946.512934.939928.322916.951911.646903.399880.425874.827870.065862.423NANANA833.494NANANA
us-gaap:RetainedEarningsAccumulatedDeficit ▁▂▁▂▂▃▄▄▄▄▃▃▃▃▃▃▂▂▂▂▃▃▄▆▇████▇▇▇▇▇▇▇▇▇▇▇▇▇▇-4892.0-4283.0-4363.0-4271.0-3678.0-2798.0-1251.0-1361.0-1410.0-1548.0-2142.0-2449.0-2420.0-2471.0-2679.0-3013.0-3090.0-3374.0-3725.0-3515.0-2807.0-2214.0-1082.01051.02818.03633.03577.03265.03054.02846.8432652.6532508.1632322.2962076.6651949.152131.0032275.8182763.9182656.2142497.6812322.5082155.0542018.445NANANA1414.327NANANA
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▂▂▂▂▁▁▂▂▃▂▄▄▆█▇▅▃▂▃-35.0-38.0-38.0-32.0-33.0-33.0-33.0-31.0-32.0-36.0-36.0-40.0-44.0-44.0-44.0-37.0-38.0-39.0-39.0-39.0-41.0-44.0-48.0-13.013.048.062.019.0-12.0-34.967-4.34248.75895.44655.607149.804192.04321.931474.998408.428229.75108.38359.44283.975NANANA84.276NANANA
us-gaap:TreasuryStockValue ██████████▇▂▁▁▁▁▁▁▁▁▁▁▁▁▁202.0202.0202.0202.0202.0202.0202.0202.0202.0202.0181.026.01.01.01.01.01.01.01.01.01.01.01.01.01.0NANANANA0.3630.3340.5070.50.4921.5321.592.3152.2952.2282.7862.7682.7483.444NANANA4.333NANANA
us-gaap:StockIssuedDuringPeriodValueNewIssues NANANA152.0NANANANANANANANANANANANANANA0.0NANANA0.00.00.0669.0NANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:StockIssuedDuringPeriodValueNewIssues us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapitalNANANA151.0NANANANANANANANANANANANANANA0.0NANANA0.00.00.0669.0NANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:StockIssuedDuringPeriodValueNewIssues us-gaap:StatementEquityComponents us-gaap:CommonStockNANANA1.0NANANANANANANANANANANANANANA0.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue 2.0NANA1.01.01.0NA3.03.03.03.05.06.07.09.09.010.010.08.08.016.026.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:NetCashProvidedByUsedInOperatingActivities ▅▆▂▂▁▂▄▃▁█▄▅▅▆▅▃▄▅▂270.0347.0121.0153.094.0160.0225.0196.0101.0442.0252.0307.0300.0364.0308.0211.0266.0312.0161.0NANANANANANANANANANANANANA505.414372.138461.465355.087392.727444.663439.606443.281460.451396.479427.523406.009391.474417.579NANANANA
us-gaap:NetCashProvidedByUsedInInvestingActivities ▁▂▂▂▂▂▂▁▁▁█▁▁▁▁▁▁▁▂-265.0-227.0-183.0-228.0-242.0-228.0-210.0-275.0-302.0-258.01354.0-320.0-381.0-294.0-331.0-315.0-272.0-334.0-205.0NANANANANANANANANANANANANA-680.302-481.162-362.252-442.612-546.603-555.21-538.466-501.676-469.19-515.458-211.123-519.354-553.681-441.473NANANANA
us-gaap:NetCashProvidedByUsedInFinancingActivities ▇▇▇███▇▇▇▇▁▇▄▇▇▇▆▇▇-7.0-129.0-20.0160.0153.068.0-39.0-47.0-10.0-19.0-1414.0-15.0-840.0-28.0-50.0-18.0-265.0-19.0-7.0NANANANANANANANANANANANANA182.95272.945-64.00264.581-10.807301.117101.04958.4394.526120.289-214.219113.594162.25524.61NANANANA
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect ▇▇▆▇▇▇▇▆▅██▇▁▇-2.0-9.0-82.085.05.00.0-24.0-126.0-211.0165.0192.0-28.0-921.042.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:AmortizationOfFinancingCosts ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▂▁▁▁▁▁█▂▁▁▁▁▁2.02.03.02.03.01.03.03.01.01.02.02.02.02.02.03.02.02.02.08.02.02.03.01.03.046.07.01.01.01.01.01.0NANANANANANANANANANANANANANANANANANA
us-gaap:DeferredIncomeTaxExpenseBenefit NANA1.00.00.0408.0-9.011.015.0-426.00.00.00.00.0-67.0-4.0NANA-2.0-20.0-1.01.0-464.0-1088.0-500.049.0129.0108.0137.0129.515124.89140.217147.87784.961-141.097-85.856-305.42570.5599.981111.275108.88788.8886.03108.50975.344109.837NANANANA
us-gaap:DepreciationDepletionAndAmortization ▂▂▂▁▁▂▂▃▂▂▃▃▃▃▃▃▃▂▁▂▂▃▅▇██▆▆▆▆▅▅▄▄▅▅▅▅▅▄▄▄▄▃▃▃100.096.090.070.084.0113.0119.0125.0121.0112.0124.0151.0142.0143.0140.0135.0123.0106.087.099.0107.0143.0215.0274.0310.0293.0249.0238.0228.92226.08215.344204.934186.867179.467208.841200.655207.83193.627190.331179.113171.62164.667157.636151.284144.006139.419NANANANA
us-gaap:IncreaseDecreaseInAccountsPayable ▆▆▅▅▄▂▄▅▂▃▅▅▇▄▆▅▅▅▅▇▄▁▄▄▅▄▆▅▄█▆▅▆▅▇▅▅▅▅▅▅▅▆▅▆▅42.033.0-2.0-8.0-35.0-86.0-17.05.0-81.0-48.05.07.070.0-17.032.014.015.0-13.03.067.0-15.0-124.0-23.0-33.013.0-35.032.0-1.0-41.34694.34629.04-3.00440.8817.31252.325-9.701-6.2614.9129.9518.9192.967-10.34740.69216.16317.005-8.078NANANANA
us-gaap:IncreaseDecreaseInAccountsReceivable ▅▆▆▅▄▄▅▄▄▁█▅▆▄▆▅▆▄▇▆▅▃▄▅▂▄▆▄▄▇▅▅▆▅▇▅▄▄▅▅▅▅▄▅▄▅7.033.056.0-12.0-41.0-53.023.0-36.0-32.0-189.0146.019.034.0-46.068.09.041.0-53.083.039.011.0-103.0-28.0-13.0-124.0-38.073.0-56.0-29.15478.15419.064-1.23958.629.68979.86525.018-26.562-42.604-14.323-10.1922.87311.983-54.175-3.157-24.698-6.458NANANANA
us-gaap:IncreaseDecreaseInInventories █▁▆▇▆▁██▆▃▇▆6.0-9.01.03.02.0-8.05.06.01.0-5.04.02.0NANA0.0-1.0NANANANANANA-2.0NANA3.01.0NANA-0.564-7.5987.2274.2781.944-1.503-8.52-4.753-3.33518.968-12.754-1.8648.625-3.058-6.6763.60311.23NANANANA
us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet ▇▅▇▄▄▄▃▇▆▆▁█▅▆▆▆▄▆25.0-1.018.0-17.0-12.0-9.0-25.017.014.011.0-47.032.02.07.012.011.0-11.014.0NANA4.0-11.0-15.0-3.085.0-69.00.0-26.01.7462.25448.443-18.469-20.676-16.037-38.453-2.1358.5712.811-16.999-3.8790.9586.54410.013-4.66114.5046.628NANANANA
us-gaap:NetCashProvidedByUsedInOperatingActivities ▅▆▂▂▁▂▄▃▁█▄▅▅▆▅▃▄▅▂270.0347.0121.0153.094.0160.0225.0196.0101.0442.0252.0307.0300.0364.0308.0211.0266.0312.0161.0NANANANANANANANANANANANANA505.414372.138461.465355.087392.727444.663439.606443.281460.451396.479427.523406.009391.474417.579NANANANA
us-gaap:NetIncomeLoss ▅▇▆▅▄▂▇▇▇█▇▆▇▇▇▇▇▇▆▅▅▄▁▂▄▇▇▇▇▇▇▇▇▇-609.080.0-92.0-593.0-880.0-1547.0110.049.0138.0594.0307.0-29.051.0208.0334.077.0284.0351.0-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078.0312.0211.0207.0194.0144.0186.0246.0128.0NANANANA158.533175.173167.454136.609149.511160.741122.069171.797157.826118.254121.1-432.83
 us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeNANA4.01.0NANA-13.01.04.00.06.0NANANA0.01.0NANANANANANA-41.0-29.0-33.0-25.029.0-27.95926.39-26.431NANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome,us-gaap:StatementEquityComponents us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome,us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditNANANA1.0NANANA1.04.00.0NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents us-gaap:RetainedEarnings▁█-609.080.0NA-593.0-880.0-1547.0NA49.0138.0594.0307.0-29.051.0208.0334.077.0284.0351.0-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078.0312.0211.0NANANANANANANANANANANANANANANANANANANANANANA
us-gaap:ShareBasedCompensation 2.0NA1.00.01.01.02.02.02.02.02.03.05.04.05.07.06.06.0NANANA9.08.06.06.06.05.04.04.514.494.3872.9212.9682.9943.5692.6772.7052.8443.9311.9332.2362.453.2082.1792.1362.297NANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:NetCashProvidedByUsedInInvestingActivities ▁▂▂▂▂▂▂▁▁▁█▁▁▁▁▁▁▁▂-265.0-227.0-183.0-228.0-242.0-228.0-210.0-275.0-302.0-258.01354.0-320.0-381.0-294.0-331.0-315.0-272.0-334.0-205.0NANANANANANANANANANANANANA-680.302-481.162-362.252-442.612-546.603-555.21-538.466-501.676-469.19-515.458-211.123-519.354-553.681-441.473NANANANA
us-gaap:PaymentsToAcquirePropertyPlantAndEquipment ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▂█▂▂▂▂▂▂▂259.0266.0194.0223.0245.0237.0207.0240.0368.0325.0209.0298.0403.0338.0347.0331.0325.0290.0272.0180.074.0122.0383.0468.0415.01171.05610.0574.0721.0541.936480.0542.0695.0518.056NANANANANANANANANANANANANANANANA
us-gaap:PaymentsToAcquireProductiveAssets ▃▃▃▃▃▃▃▄▄▃▄▄▅▄▄▄▄▄▃▂▁▃▅▅▆▆▄▇▇▆▆▆█▆▆▆▇▇▇▆▆▆▇▆▆▅266.0227.0196.0228.0244.0228.0222.0291.0328.0258.0282.0324.0382.0302.0325.0324.0279.0340.0202.0150.045.0196.0406.0418.0466.0508.0330.0569.0610.213533.787525.104551.909692.0483.634484.004483.09583.03557.631640.925518.891498.519526.139567.095520.769543.188442.122NANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
us-gaap:NetCashProvidedByUsedInFinancingActivities ▇▇▇███▇▇▇▇▁▇▄▇▇▇▆▇▇-7.0-129.0-20.0160.0153.068.0-39.0-47.0-10.0-19.0-1414.0-15.0-840.0-28.0-50.0-18.0-265.0-19.0-7.0NANANANANANANANANANANANANA182.95272.945-64.00264.581-10.807301.117101.04958.4394.526120.289-214.219113.594162.25524.61NANANANA
 us-gaap:ProceedsFromIssuanceOfLongTermDebt us-gaap:BusinessAcquisition,us-gaap:DebtInstrument,us-gaap:LongtermDebtType swn:MontageResourcesCorporation,swn:EightPointThreeSevenFivePercentSeniorNotesDueSeptember2028,us-gaap:SeniorNotesNANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:ProceedsFromIssuanceOfLongTermDebt us-gaap:DebtInstrument,us-gaap:LongtermDebtType swn:EightPointThreeSevenFivePercentSeniorNotesDueSeptember2028,us-gaap:SeniorNotesNANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value7000000.07000000.07000000.07000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.05000000.05000000.05000000.05000000.05000000.05000000.04000000.04000000.04000000.04000000.04000000.04000000.04000000.04000000.04000000.03531000.03529000.03517000.03515000.03516000.03511000.03504000.03492000.03492000.03491000.03483000.03481000.03480000.03477000.03461000.0
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.20.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.00.00.00.00.00.00.00.00.00.00.00.00.10.10.00.00.00.00.00.10.10.10.1

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value676679571541540540539541581582573502498494482385382382382375352352351351351350348348349349349349349349349
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic


Weighted
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value676675571541540539539539581581571499496493482385382382382375351351351350350350348348348347347346345345345
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount


Antidilutive
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-31
Value107.7823829.583819109.1792147.4797857.1297337.2701965.4650725.21151515818278798386
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecurities

swn:UnvestedShareBasedPayment


Antidilutive
Period End2021-06-302020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value0.7216330.9399410.9026151.006862.1364531.7730741.8813553.4638024.3357155.2924545.7030866.1063221.212396
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount7.19.88.411.028.624.925.963.483.233.47.07.41.6

us-gaap:EmployeeStockOption


Antidilutive
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-30
Value3.7339713.7950914.4258864.5487354.5845635.1028825.1147635.128640.0007170.00.00.1809321.8540043.4095964.0288195.7325213.7967783.8325333.7040891.2548420.6541891.1799141.5508381.5992462.1126791.6642321.723316
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount36.648.846.242.149.968.271.770.50.00.00.00.22.44.34.86.60.00.00.00.00.00.00.00.00.00.00.0

us-gaap:PerformanceShares


Antidilutive
Period End2021-06-302020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302016-09-302016-06-302016-03-312015-09-302015-06-30
Value2.8320432.2822112.7122072.2754980.240450.2418960.2602012.0005530.87580.5749441.0364221.268040.935330.780920.2972970.0898020.129202
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount27.823.825.124.83.23.43.636.616.83.61.31.51.20.90.30.00.0

us-gaap:RestrictedStockUnitsRSU


Antidilutive
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-06-302019-03-31
Value2.9174273.9872911.9357812.6317271.3122930.00.0
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount28.651.220.224.414.30.00.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareBasic


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value-0.90.12-0.14-1.04-1.63-2.860.20.090.261.10.54-0.050.090.360.530.090.450.57-0.48-1.52-1.61-3.03-5.58-4.62-2.130.120.890.60.590.550.410.530.70.36-1.02-0.42-1.40.310.470.50.480.390.430.470.350.50.460.340.35-1.26
Percentage of EarningsPerShareBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareDiluted


Earnings
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value-0.90.12-0.14-1.04-1.63-2.860.20.090.261.10.54-0.050.090.360.530.090.450.57-0.48-1.52-1.61-3.03-5.58-4.62-2.130.120.880.60.590.550.410.530.70.36-1.02-0.42-1.40.310.450.50.480.390.430.460.350.490.450.340.35-1.26
Percentage of EarningsPerShareDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Allocated Share Based Compensation Expense

us-gaap:AllocatedShareBasedCompensationExpense

us-gaap:AllocatedShareBasedCompensationExpense


Allocated
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value9.0132.06.00.01.04.07.03.05.04.07.06.06.06.014236.06.06.04.04.04.492.9212.9682.994-2.7992.6772.7052.844-1.661.9332.2362.45-1.9062.1792.1362.297
Percentage of AllocatedShareBasedCompensationExpense100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.91.20.41.50.00.20.60.70.30.60.40.90.70.70.92.74.00.80.80.60.40.40.40.30.30.4-0.40.40.50.4-0.20.30.30.4-0.30.30.40.3

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:ComprehensiveIncomeNetOfTax


Comprehensive
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-606.080-98.0-592.0-880.0-1547.010850142594311-25.05120832778285351-210.0-706.0-590.0-1128.0-2142.0-1765.0-823.0643552422301639113928533-224.089-274.706-641.16717433729621611278209108207
Percentage of ComprehensiveIncomeNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-57.77.5-12.6-112.3-214.6-261.314.57.921.360.026.5-2.66.222.640.410.635.141.5-30.7-108.4-113.0-194.8-311.8-235.6-107.76.936.926.122.214.710.116.033.14.5-29.0-40.1-106.926.545.338.628.316.611.730.718.431.0

Cost Of Goods And Services Sold

us-gaap:CostOfGoodsAndServicesSold us-gaap:ProductOrService

us-gaap:CostOfGoodsAndServicesSold

us-gaap:NaturalGasGatheringTransportationMarketingAndProcessing


Cost
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value333356271226201248298288293441421288265255236236
Percentage of CostOfGoodsAndServicesSold100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax31.733.234.842.949.041.940.045.343.944.535.830.332.527.729.232.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:NaturalGasGatheringTransportationMarketingAndProcessing0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Costs And Expenses

us-gaap:CostsAndExpenses

us-gaap:CostsAndExpenses


Costs
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value75777110239081166208268166564577782388569266564262762358056213761014167932483591204876867764266867858955953648110669061387470480471482443413412383380
Percentage of CostsAndExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax72.171.9131.3172.3284.4351.791.4104.696.778.570.093.184.872.379.485.176.868.682.2211.4194.3290.0472.8479.4268.182.370.469.264.560.965.064.462.365.7138.0132.1231.371.764.561.563.165.661.760.465.056.9

Gains Losses On Extinguishment Of Debt

us-gaap:GainsLossesOnExtinguishmentOfDebt

us-gaap:GainsLossesOnExtinguishmentOfDebt


Gains
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-04-262018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value0.00.07.0281.07.00.00.0-9.00.0-8.0-8.00.0-59.0-10.0-1.00.0-51.0
Percentage of GainsLossesOnExtinguishmentOfDebt0.00.0100.0100.0100.0100.00.00.0100.00.0100.0100.00.0100.0100.0100.00.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.01.74.70.11.10.00.0-0.80.00.0-1.00.0-8.0-1.2-0.10.0-7.8

us-gaap:GainsLossesOnExtinguishmentOfDebt us-gaap:LongtermDebtType

us-gaap:SeniorNotes


Gains
Period End2020-09-302020-06-302020-03-312019-09-302018-12-312017-09-302016-07-31
Value0.07.0287.0-9.0-59.0-51.0
Percentage of GainsLossesOnExtinguishmentOfDebt0.0100.0100.0100.0100.0100.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.01.74.70.00.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:SeniorNotes0.00.00.00.00.00.00.0

us-gaap:GainsLossesOnExtinguishmentOfDebt us-gaap:StatementBusinessSegments

us-gaap:CorporateAndOther


Gains
Period End2020-09-302020-06-302020-03-312019-09-302018-12-312018-09-302018-06-302017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value0.07.0287.0-9.00.0-8.00.0-59.0-10.0-1.00.0-51.0
Percentage of GainsLossesOnExtinguishmentOfDebt0.0100.0100.0100.0100.00.0100.00.0100.0100.0100.00.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.01.74.71.1-0.80.0-1.00.0-8.0-1.2-0.10.0-7.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:CorporateAndOther0.00.00.00.00.00.00.00.00.00.00.00.00.0

Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments


Income
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-609.080-593.0-880.0-1141.059153168308-29.05120825563284351-219.0-728.0-594.0-1131.0-2580.0-2827.0-1281.0127428351347323257310409212-304.63-230.57-793.425178259289276225249263200281
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-58.07.5-112.5-214.6-192.79.322.917.026.2-3.06.222.631.58.535.041.5-32.0-111.8-113.8-195.3-375.5-377.4-167.713.644.537.833.529.028.435.747.529.0-39.4-33.6-132.327.234.837.836.133.437.338.733.942.1

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxExpenseBenefit


Income
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1.00.00.0406-10.010.015-426.01.00.00.00.0-79.0-14.0-9.0-20.0-1.01.0-473.0-1088.0-493.04911614014012811312416485-122.777-85.755-305.325701001141088810010378109
Percentage of IncomeTaxExpenseBenefit100.00.00.0100.0100.0100.0100.0100.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.10.00.068.6-1.31.62.2-43.00.10.00.00.0-9.8-1.9-1.3-3.1-0.20.2-68.9-145.3-64.55.312.115.113.511.612.514.319.011.6-15.9-12.5-50.910.813.515.014.213.215.015.113.216.4

us-gaap:IncomeTaxExpenseBenefit us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Income
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312017-12-312017-09-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value0.00.040610.015-426.0-79.0-14.0-9.0-20.0-1.01.0-549.0-1112.0-630.0189310710598
Percentage of IncomeTaxExpenseBenefit0.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0116.1102.2127.836.780.276.475.076.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.068.61.62.2-43.0-9.8-1.9-1.3-3.1-0.20.2-79.9-148.5-82.51.99.711.510.18.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:ExplorationAndProduction0.00.0115.02.83.9-77.30.0-2.90.0-5.2-0.30.30.0-226.5-127.02.70.016.414.612.3

Interest Expense

us-gaap:InterestExpense

us-gaap:InterestExpense


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value303131222219191715142429323938313432312617144.00.01.0512013121212119.2789.0219.352108.3617.3384.8125.6576.177.4366.8866.5896.186.508
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.92.94.04.25.43.22.62.72.21.42.03.03.94.24.74.24.23.84.54.03.32.40.60.00.15.52.11.41.21.21.41.31.11.21.21.51.41.10.60.70.81.11.01.01.01.0

us-gaap:InterestExpense us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Interest
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value303122221917151429323938313432312616142.00.00.0451810.010.09.0
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.094.1100.050.00.00.088.290.076.983.369.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.92.94.25.43.22.72.21.43.03.94.24.74.24.23.84.54.03.12.40.30.00.04.81.91.11.00.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:ExplorationAndProduction4.24.37.19.95.44.83.92.54.56.16.10.06.56.45.70.06.85.54.10.00.00.06.80.01.51.41.1

Interest Expense Debt

us-gaap:InterestExpenseDebt

us-gaap:InterestExpenseDebt


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value48504843404041424142515659656458595858595653475152502625252525252524242523191716161514141413
Percentage of InterestExpenseDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax4.64.76.28.29.86.85.56.66.14.24.35.97.27.17.97.97.36.98.59.110.79.26.86.86.85.42.72.72.42.32.82.92.93.33.13.74.03.02.32.22.22.22.22.12.42.1

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value-609.080-92.0-593.0-880.0-1547.011049138594307-29.05120833477284351-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078312211207194144186246128158175167136149160122171157118121-432.83
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 RevenueFromContractWithCustomerExcludingAssessedTax-58.07.5-11.8-112.5-214.6-261.314.87.720.760.026.1-3.06.222.641.310.435.041.5-30.7-108.8-113.6-195.5-306.7-232.2-103.18.432.422.720.017.415.921.428.517.421.322.821.920.222.323.620.725.725.323.525.4-80.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome


Net
Period End2020-12-312020-09-302019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312017-09-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value4.01.0-13.01.04.00.06.00.01.0-41.0-29.0-33.0-25.029-27.95926-26.431
Percentage of NetIncomeLoss-4.3-0.2-11.82.02.90.02.00.01.31.91.74.2-32.19.3-13.312.7-13.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.50.2-1.70.20.60.00.50.00.1-6.0-3.9-4.3-2.73.0-3.02.5-2.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCredit


Net
Period End2020-09-302019-09-302019-06-302019-03-31
Value1.01.04.00.0
Percentage of NetIncomeLoss-0.22.02.90.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.20.20.60.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCredit0.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-30
Value-609.080-593.0-880.0-1547.049138594307-29.05120833477284351-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078312211
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-58.07.5-112.5-214.6-261.37.720.760.026.1-3.06.222.641.310.435.041.5-30.7-108.8-113.6-195.5-306.7-232.2-103.18.432.422.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Net Income Loss Available To Common Stockholders Basic

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic

us-gaap:NetIncomeLossAvailableToCommonStockholdersBasic


Net
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value-92.0-593.0-880.0-1547.011049138594307-29.05120526743224281-237.0-735.0-620.0-1159.0-2134.0-1766.0-815.046312211207194
Percentage of NetIncomeLossAvailableToCommonStockholdersBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-11.8-112.5-214.6-261.314.87.720.760.026.1-3.06.222.333.05.827.633.2-34.6-112.9-118.8-200.2-310.6-235.8-106.74.932.422.720.017.4

Operating Income Loss

us-gaap:OperatingIncomeLoss

us-gaap:OperatingIncomeLoss


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value293301-244.0-381.0-756.0-1490.064-29.02221335266124255167110188266122-725.0-492.0-1100.0-2561.0-2842.0-1284.0165285286367434317309325251-577.304-220.202-787.641185263295282232256270206288266197202-700.492
Percentage of OperatingIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax27.928.1-31.3-72.3-184.4-251.78.6-4.63.321.530.06.915.227.720.614.923.231.417.8-111.4-94.3-190.0-372.8-379.4-168.117.729.630.835.539.135.035.637.734.3-74.7-32.1-131.328.335.538.536.934.438.339.635.043.142.639.242.3-129.5

us-gaap:OperatingIncomeLoss us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Operating
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value286295-379.0-748.0-1486.0-21.030210175972381146414622582-777.0-549.0-1160.0-2633.0-2910.0-1639.078196189275352
Percentage of OperatingIncomeLoss97.698.099.598.999.772.4136.498.6265.278.293.368.358.277.784.667.2107.2111.6105.5102.8102.4127.647.368.866.174.981.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax27.227.5-71.9-182.4-251.0-3.34.521.218.411.925.914.18.718.026.612.0-119.4-105.2-200.3-383.3-388.5-214.58.420.420.426.631.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:ExplorationAndProduction39.841.0-123.1-335.4-421.0-5.97.938.127.418.437.00.013.427.539.80.0-203.9-188.7-338.20.0-592.7-330.411.80.029.038.144.2

swn:Marketing


Operating
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value7.06.0-2.0-8.0-4.0-8.0-8.0
Percentage of OperatingIncomeLoss2.42.00.51.10.327.6-36.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.70.6-0.4-2.0-0.7-1.3-1.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:Marketing2.11.7-0.9-4.3-1.7-2.9-2.8

Other Comprehensive Income Loss Net Of Tax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax


Other
Period End2020-09-302020-06-302019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-30
Value1.00.01.04.00.04.04.00.00.0-7.01.01.00.02.03.04.0-35.0-26.0-35.0-14.0433122-30.625-53.1-46.68839-94.197-42.236-129.891
Percentage of OtherComprehensiveIncomeLossNetOfTax100.00.0100.0100.00.0100.0100.00.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.20.00.20.60.00.30.40.00.0-0.90.10.10.00.30.60.7-5.1-3.5-4.6-1.54.53.32.2-2.8-5.9-5.44.6-12.8-5.5-18.9

us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Other
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312017-12-312017-09-302016-12-312016-09-302016-06-302016-03-312015-12-312014-03-312013-12-312013-09-302013-06-302013-03-31
Value1.00.00.01.04.00.04.0-13.01.00.02.03.01.0-2.00.081110.2660.2670.267
Percentage of OtherComprehensiveIncomeLossNetOfTax100.00.00.0100.0100.00.0100.0185.7100.00.0100.0100.025.05.7-0.3-22.5-0.60.7-0.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.20.00.00.20.60.00.3-1.60.10.00.30.60.2-0.30.01.30.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Other
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302017-12-312017-09-302017-06-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-30
Value1.00.00.01.04.00.04.04.0-7.01.01.00.02.03.04.0-35.0-26.0-35.0-14.0433122-30.625-53.1-46.68839-94.197-42.236-129.891
Percentage of OtherComprehensiveIncomeLossNetOfTax100.00.00.0100.0100.00.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.20.00.00.20.60.00.30.4-0.90.10.10.00.30.60.7-5.1-3.5-4.6-1.54.53.32.2-2.8-5.9-5.44.6-12.8-5.5-18.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense

us-gaap:OtherNonoperatingIncomeExpense


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-1000000.01000000.0-2000000.02000000.001000000.00-2000000.0-6000000.01000000.0-1000000.0-1000000.03000000.0-1000000.0-1000000.0-2000000.06000000.02000000.03000000.00-3000000.0-32000000.003000000.0-1000000.0-5000000.00-193000.01193000.02705000.0-319000.0354000.0-533000.0-1585000.0238000.02577000.0-200000.0-57000.0-122000.069000.0374000.0162000.0326000.0-84000.023000.0
Percentage of OtherNonoperatingIncomeExpense100.0100.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.10.1-0.30.40.00.20.0-0.3-0.90.1-0.1-0.10.4-0.1-0.1-0.30.70.20.50.0-0.5-4.70.00.4-0.1-0.50.0-0.00.10.3-0.00.0-0.1-0.20.00.4-0.0-0.0-0.00.00.10.00.0-0.00.0

us-gaap:OtherNonoperatingIncomeExpense us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCredit


Other
Period End2020-09-302019-09-302019-06-302019-03-31
Value2000000.02000000.05000000.00
Percentage of OtherNonoperatingIncomeExpense100.0-100.0-83.30.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.40.30.70.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCredit0.00.00.00.0

us-gaap:OtherNonoperatingIncomeExpense us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value-1000000.01000000.02000000.0-1000000.01000000.0-4000000.0-5000000.01000000.003000000.00-1000000.01000000.02000000.02000000.02000000.02000000.03000000.0-2000000.0-23000000.003000000.0-1000000.0-4000000.00-1000000.02000000.0
Percentage of OtherNonoperatingIncomeExpense100.0100.0100.00.0100.0200.083.3100.0-0.0100.0-0.0100.0-50.033.3100.00.066.70.066.771.90.0100.0100.080.00.0518.1167.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.10.10.4-0.20.2-0.6-0.70.10.00.40.0-0.10.10.20.20.30.30.6-0.3-3.30.00.4-0.1-0.40.0-0.10.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:ExplorationAndProduction-0.10.10.6-0.40.3-1.1-1.30.20.00.60.00.00.20.40.40.00.51.0-0.60.00.00.6-0.20.00.0-0.10.3

us-gaap:CorporateAndOther


Other
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-03-312016-12-312016-09-302016-06-30
Value01000000.002000000.0-1000000.00000-1000000.0-1000000.00-1000000.0
Percentage of OtherNonoperatingIncomeExpense0.00.00.0-100.016.70.0-0.00.0-0.0-50.00.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.20.00.3-0.10.00.00.00.0-0.1-0.10.0-0.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:CorporateAndOther0.00.00.00.00.00.00.00.00.00.00.00.00.0

Revenue From Contract With Customer Excluding Assessed Tax

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value10501072779527410592745636667990117595181692080973781184668465152257968774976493396292810351112907868862733772685599656744767765676670682589668624502477540
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ConsolidationItems

us-gaap:IntersegmentElimination


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value637630-1941.0266190300-2642.0304330493-700.0-594.0-501.0613-502.0-467.0-537.0-575.0-438.0-409.0-321.0-378.0-421.0-486.0-492.0-661.0-732.0-710.0821918-636.0-602.0643498
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax60.758.8-249.250.546.350.7-354.647.849.549.8-59.6-62.5-61.466.6-62.1-63.4-66.2-68.0-64.0-62.8-61.5-65.3-61.3-64.9-64.4-70.8-76.1-76.579.382.5-70.1-69.374.668.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax60.758.8-249.250.546.350.7-354.647.849.549.8-59.6-62.5-61.466.6-62.1-63.4-66.2-68.0-64.0-62.8-61.5-65.3-61.3-64.9-64.4-70.8-76.1-76.579.382.5-70.1-69.374.668.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ConsolidationItems, us-gaap:ProductOrService

us-gaap:IntersegmentElimination, swn:GasSales


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value12-13.066-9.0-9.0-9.059-8.0-8.0-9.07.05.07.0-5.04.06.05.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.1-1.28.5-1.7-2.2-1.57.9-1.3-1.2-0.90.60.50.9-0.50.50.80.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.1-1.28.5-1.7-2.2-1.57.9-1.3-1.2-0.90.60.50.9-0.50.50.80.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination swn:GasSales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, swn:Marketing


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value651644-2015.0276202309-2706.0313339502-677.0-559.0-463.0576-458.0-423.0-490.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax62.060.1-258.752.449.352.2-363.249.250.850.7-57.6-58.8-56.762.6-56.6-57.4-60.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax62.060.1-258.752.449.352.2-363.249.250.850.7-57.6-58.8-56.762.6-56.6-57.4-60.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination swn:Marketing100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, swn:NaturalGasLiquidsSales


Revenue
Period End2021-06-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1.00.00.00.00.00.00.0-1.00.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.10.00.00.00.00.00.0-0.10.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.10.00.00.00.00.00.0-0.10.00.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination swn:NaturalGasLiquidsSales100.00.00.00.00.00.00.0100.00.00.00.0

us-gaap:IntersegmentElimination, swn:OilSales


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value1.0-1.08.0-1.0-3.00.05.0-1.0-1.00.01.01.00.0-1.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.1-0.11.0-0.2-0.70.00.7-0.2-0.10.00.10.10.0-0.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.1-0.11.0-0.2-0.70.00.7-0.2-0.10.00.10.10.0-0.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination swn:OilSales100.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.00.0100.0

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

us-gaap:OperatingSegments, swn:GasSales, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value421451190155239230267421460400535
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax40.142.136.137.840.436.240.042.548.449.058.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax40.142.136.137.840.436.240.042.548.449.058.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:GasSales swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:Marketing, swn:Marketing


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value983996495389548592626
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax93.692.993.994.992.693.193.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax93.692.993.994.992.693.193.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:Marketing swn:Marketing100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:NaturalGasLiquidsSales, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value1781736840505258811127565
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax17.016.112.99.88.48.28.78.211.89.27.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax17.016.112.99.88.48.28.78.211.89.27.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:NaturalGasLiquidsSales swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:OilSales, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value10580391652664639614434
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax10.07.57.43.98.810.46.93.96.45.43.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax10.07.57.43.98.810.46.93.96.45.43.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:OilSales swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:Other, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value0.01.01.00.03.00.00.01.00.01.03.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.20.00.50.00.00.10.00.10.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.20.00.50.00.00.10.00.10.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:Other swn:ExplorationAndProduction0.0100.0100.00.0100.00.00.0100.00.0100.0100.0

us-gaap:OperatingSegments, swn:Other, swn:Marketing


Revenue
Period End2021-06-302021-03-312019-09-30
Value0.01.00.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:Other swn:Marketing0.0100.00.0

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

us-gaap:IntersegmentElimination, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value-14.0-14.0-10.0-12.0-9.0-9.0-9.0-9.06.07.0-6.05.06.05.03.05.03.07.07.07.03.06.05.01.0-3.0-4.0-6.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-1.3-1.3-1.9-2.9-1.5-1.4-1.3-0.90.60.9-0.70.60.80.60.40.70.51.31.21.00.40.80.50.1-0.3-0.4-0.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-1.3-1.3-1.9-2.9-1.5-1.4-1.3-0.90.60.9-0.70.60.80.60.40.70.51.31.21.00.40.80.50.1-0.3-0.4-0.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IntersegmentElimination, swn:Marketing


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value651644276202309313339
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax62.060.152.449.352.249.250.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax62.060.152.449.352.249.250.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:IntersegmentElimination swn:Marketing100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value704705298211344348371542633520637
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax67.065.856.551.558.154.755.654.766.663.769.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax67.065.856.551.558.154.755.654.766.663.769.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:Marketing


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value983997495389548592626
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax93.693.093.994.992.693.193.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax93.693.093.994.992.693.193.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:Marketing100.0100.0100.0100.0100.0100.0100.0

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

us-gaap:OperatingSegments, srt:OtherProperty, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value0.01.01.00.00.00.01.01.04.02.02.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.20.00.00.00.10.10.40.20.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.10.20.00.00.00.10.10.40.20.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments srt:OtherProperty swn:ExplorationAndProduction0.0100.0100.00.00.00.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:NortheastAppalachia, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value230263131117195175217348254213327
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax21.924.524.928.532.927.532.535.226.726.135.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax21.924.524.928.532.927.532.535.226.726.135.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:NortheastAppalachia swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:SouthwestAppalachia, swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value47444116694149173153193235166156
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax45.141.131.522.925.227.222.919.524.720.317.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax45.141.131.522.925.227.222.919.524.720.317.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments swn:SouthwestAppalachia swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ProductOrService

swn:GasSales


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value433464356199164248298238275430586465407540425394471
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax41.243.345.737.840.041.940.037.441.243.449.948.949.958.752.553.558.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax41.243.345.737.840.041.940.037.441.243.449.948.949.958.752.553.558.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:GasSales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:Marketing


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value332352272219187239293279287438417287265253236233250
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax31.632.834.941.645.640.439.343.943.044.235.530.232.527.529.231.630.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax31.632.834.941.645.640.439.343.943.044.235.530.232.527.529.231.630.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:Marketing100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:NaturalGasLiquidsSales


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value179173107684050835258811001127565745537
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax17.016.113.712.99.88.411.18.28.78.28.511.89.27.19.17.54.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax17.016.113.712.99.88.411.18.28.78.28.511.89.27.19.17.54.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:NaturalGasLiquidsSales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:OilSales


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value10681434019527067473955624435292723
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax10.17.65.57.64.68.89.410.57.03.94.76.55.43.83.63.72.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax10.17.65.57.64.68.89.410.57.03.94.76.55.43.83.63.72.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:OilSales100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:Other


Revenue
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.02.01.01.00.03.01.00.00.02.01.00.01.03.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.20.10.20.00.50.10.00.00.20.10.00.10.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.00.20.10.20.00.50.10.00.00.20.10.00.10.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:Other0.0100.0100.0100.00.0100.0100.00.00.0100.0100.00.0100.0100.0

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value718719308223353357380551639527643532476531566420381291343448491496660681652721796
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax68.467.158.454.459.656.157.055.767.264.669.965.864.665.566.961.458.555.759.265.265.664.970.770.870.369.771.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax68.467.158.454.459.656.157.055.767.264.669.965.864.665.566.961.458.555.759.265.265.664.970.770.870.369.771.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:Marketing


Revenue
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value332353219187239279287
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax31.632.941.645.640.443.943.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax31.632.941.645.640.443.943.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax swn:Marketing100.0100.0100.0100.0100.0100.0100.0

Revenues

us-gaap:Revenues

us-gaap:Revenues


Revenues
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value10501072779527410592745636667990117595181692080973781184668465152257968774976493396292810351112907868862733772685599656744767765676670682589668624502477540
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Selling General And Administrative Expense

us-gaap:SellingGeneralAndAdministrativeExpense

us-gaap:SellingGeneralAndAdministrativeExpense


Selling
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value34383231322647424037445159556362585076615654586060685954525655504737453644484535403740353632
Percentage of SellingGeneralAndAdministrativeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax3.23.54.15.97.84.46.36.66.03.73.75.47.26.07.88.47.25.911.19.410.79.38.48.07.97.36.15.85.05.16.15.95.55.15.95.37.57.46.14.65.35.56.15.26.24.9

Assets

us-gaap:Assets

us-gaap:Assets


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302009-12-31
Value53945247516041574555527567176598654564465797705870427713752172027150719670766890737785188110107251350415587149259177888784238047789476356916673770727503855479027214674263406017599255904770
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Assets us-gaap:ConsolidationItems

swn:CorporateAndReconcilingItems


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value1251683861124
Percentage of Assets2.42.56.714.9
Percentage of Assets2.42.56.714.9
Percentage of Assets swn:CorporateAndReconcilingItems100.0100.0100.0100.0

us-gaap:Assets us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, swn:ExplorationAndProductionReportableSegment


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value4654623548725109
Percentage of Assets90.292.884.067.9
Percentage of Assets90.292.884.067.9
Percentage of Assets us-gaap:OperatingSegments swn:ExplorationAndProductionReportableSegment100.0100.0100.0100.0

us-gaap:OperatingSegments, swn:MarketingReportableSegment


Assetsus-gaap:
Period End2020-12-312019-12-312018-12-312017-12-31
Value3813145391288
Percentage of Assets7.44.79.317.1
Percentage of Assets7.44.79.317.1
Percentage of Assets us-gaap:OperatingSegments swn:MarketingReportableSegment100.0100.0100.0100.0

us-gaap:Assets us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Assetsus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-31
Value48704741370541854900609959455562573255835346510948424633441341784015500055386588915911882137031301874617127662163575194
Percentage of Assets90.390.489.191.992.992.490.886.381.279.369.367.967.264.861.359.058.367.865.081.285.488.087.987.281.380.278.679.077.1
Percentage of Assets90.390.489.191.992.992.490.886.381.279.369.367.967.264.861.359.058.367.865.081.285.488.087.987.281.380.278.679.077.1
Percentage of Assets swn:ExplorationAndProduction100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:Marketing


Assetsus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value408396240208214272277
Percentage of Assets7.67.55.84.64.14.14.2
Percentage of Assets7.67.55.84.64.14.14.2
Percentage of Assets swn:Marketing100.0100.0100.0100.0100.0100.0100.0

us-gaap:CorporateAndOther


Assetsus-gaap:
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-31
Value116110212162161227323542386211231115011241120123615151567162211501760208215246242343
Percentage of Assets2.22.15.13.63.13.44.98.46.73.03.314.914.915.617.321.122.123.515.620.72.62.01.81.62.3
Percentage of Assets2.22.15.13.63.13.44.98.46.73.03.314.914.915.617.321.122.123.515.620.72.62.01.81.62.3
Percentage of Assets us-gaap:CorporateAndOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:LiabilitiesAndStockholdersEquity


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value539452475160415745555275671765986545644657977058704277137521720271507196707668907377851881101072513504155871492591778887842380477894763569166737707275038554790272146742634060174770
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-312010-12-312009-12-31
Value-18.0586497384823170132463135308229372362220522502193197916521573127891711235731148228244376218705746624293404236223036396929642331
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-0.311.29.69.218.132.248.347.547.145.640.731.232.028.426.322.922.017.813.016.37.813.528.141.446.045.331.246.845.545.045.150.249.348.9

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value-21.0-24.0-24.0-18.0-19.0-19.0-19.0-17.0-18.0-22.0-22.0
Percentage of StockholdersEquity116.7-4.1-4.8-4.7-2.3-1.1-0.6-0.5-0.6-0.7-0.9
Percentage of Assets-0.4-0.5-0.5-0.4-0.4-0.4-0.3-0.3-0.3-0.3-0.4
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value-35.0-38.0-38.0-32.0-33.0-33.0-33.0-31.0-32.0-36.0-36.0-40.0-44.0-44.0-44.0-37.0-38.0-39.0-39.0-39.0-41.0-44.0-48.0-13.013486219-12.0-4.0150408
Percentage of StockholdersEquity194.4-6.5-7.6-8.3-4.0-1.9-1.0-1.0-1.0-1.2-1.5-1.8-2.0-2.0-2.2-2.2-2.4-3.1-4.3-3.5-7.2-3.8-2.1-0.30.20.71.30.4-0.3-0.14.910.3
Percentage of Assets-0.6-0.7-0.7-0.8-0.7-0.6-0.5-0.5-0.5-0.6-0.6-0.6-0.6-0.6-0.6-0.5-0.5-0.5-0.6-0.6-0.6-0.5-0.6-0.10.10.30.40.2-0.1-0.02.25.2
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value5104510250934882473047284726472347204717471547144709470346984698469746874677467334183403340933963384337210191005996969934903
Percentage of StockholdersEquity-28355.6870.61024.71271.4574.7278.0145.6150.7153.1160.6199.6213.8209.3214.5237.4284.4298.6366.7510.0416.1596.5296.4149.476.554.447.821.923.424.626.830.822.8
Percentage of Assets94.697.298.7117.4103.889.670.471.672.173.281.366.866.961.062.565.265.765.166.167.846.340.042.031.725.121.66.811.011.212.013.911.4
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value7.07.07.07.06.06.06.06.06.06.06.06.06.06.05.05.05.05.05.05.04.04.04.04.04.04.04.04.04.04.04.04.0
Percentage of StockholdersEquity-38.91.21.41.80.70.40.20.20.20.20.30.30.30.30.30.30.30.40.50.40.70.30.20.10.10.10.10.10.10.10.10.1
Percentage of Assets0.10.10.10.20.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.00.00.00.00.00.00.00.00.00.10.1
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value-4892.0-4283.0-4363.0-4271.0-3678.0-2798.0-1251.0-1361.0-1410.0-1548.0-2142.0-2449.0-2420.0-2471.0-2679.0-3013.0-3090.0-3374.0-3725.0-3515.0-2807.0-2214.0-1082.0105128183633357732653054265319492656
Percentage of StockholdersEquity27177.8-730.9-877.9-1112.2-446.9-164.5-38.5-43.4-45.7-52.7-90.7-111.1-107.6-112.7-135.4-182.4-196.4-264.0-406.2-313.0-489.9-192.9-47.423.745.351.576.776.175.673.264.266.9
Percentage of Assets-90.7-81.6-84.6-102.7-80.7-53.0-18.6-20.6-21.5-24.0-37.0-34.7-34.4-32.0-35.6-41.8-43.2-46.9-52.6-51.0-38.1-26.0-13.39.820.923.324.035.634.433.028.933.6
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302012-12-312011-12-31
Value-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-181.0-26.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-2.0
Percentage of StockholdersEquity1122.2-34.5-40.6-52.6-24.5-11.9-6.2-6.4-6.6-6.9-7.7-1.2-0.0-0.0-0.1-0.1-0.1-0.1-0.1-0.1-0.2-0.1-0.0-0.0-0.0-0.0-0.1
Percentage of Assets-3.7-3.8-3.9-4.9-4.4-3.8-3.0-3.1-3.1-3.1-3.1-0.4-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets Current

us-gaap:AssetsCurrent

us-gaap:AssetsCurrent


Assets
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value593602671613770972679633764887956615567148815091476157917891872188912781884393570699888111566066268364473979261680884610031228978836686557580564
Percentage of AssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets11.011.513.014.716.918.410.19.611.713.816.58.78.119.320.120.522.124.926.527.417.322.14.85.35.25.77.57.27.48.18.09.410.48.912.012.013.414.412.411.610.28.89.711.8

Cash

us-gaap:Cash

us-gaap:Cash


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value2.04.013937.05.05.09.07189328.02026726125926326525431125715
Percentage of Cash100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.10.32.20.20.10.10.11.11.40.60.10.33.53.53.63.73.73.60.40.20.70.2

Cash And Cash Equivalents At Carrying Value

us-gaap:CashAndCashEquivalentsAtCarryingValue

us-gaap:CashAndCashEquivalentsAtCarryingValue


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312008-12-312007-12-31
Value2.04.0139510.05.05.0291553662019.037958916989111113821423147499815971515371753202018221825175318412061513131716141313131961.832
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.10.32.30.20.10.10.42.45.73.50.10.512.412.213.715.519.220.121.413.518.70.20.10.30.10.40.20.20.20.30.20.30.30.80.30.62.40.20.20.20.30.30.20.20.00.30.00.0

us-gaap:CashAndCashEquivalentsAtCarryingValue us-gaap:ConsolidationItems

swn:CorporateAndReconcilingItems


Cash
Period End2020-12-312019-12-312018-12-312017-12-31
Value135.0205914
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0102.099.8
Percentage of Assets0.30.13.512.2
Percentage of Assets swn:CorporateAndReconcilingItems10.43.053.181.3

us-gaap:CashAndCashEquivalentsAtCarryingValue us-gaap:StatementBusinessSegments

us-gaap:CorporateAndOther


Cash
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-31
Value2.04.09510.05.0291553662019.0379589891100140015009981600
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.099.0101.3101.8100.0100.2
Percentage of Assets0.00.12.30.20.10.42.45.73.50.10.512.413.715.419.521.813.518.8
Percentage of Assets us-gaap:CorporateAndOther1.73.644.86.23.112.848.067.552.14.316.083.388.389.092.492.586.890.9

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-31
Value2.04.0139510.05.05.0291553662019.0379589161423
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.10.32.30.20.10.10.42.45.73.50.10.512.412.220.1

Accounts Receivable Net Current

us-gaap:AccountsReceivableNetCurrent us-gaap:ConsolidationItems

us-gaap:AccountsReceivableNetCurrent

swn:CorporateAndReconcilingItems


Accounts
Period End2020-12-312018-12-31
Value1000000.04000000.0
Percentage of AccountsReceivableNetCurrent100.0100.0
Percentage of Assets0.00.1
Percentage of Assets swn:CorporateAndReconcilingItems0.81.0

Receivables Net Current

us-gaap:ReceivablesNetCurrent

us-gaap:ReceivablesNetCurrent


Receivables
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value408400368239250292345323358390581397416382428360351310363274235224327355386491530457513542464444445387377297272299341346336339351263
Percentage of ReceivablesNetCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets7.67.67.15.75.55.55.14.95.56.110.05.65.95.05.75.04.94.35.14.03.22.64.03.32.93.23.65.05.86.45.85.65.85.65.64.23.63.54.34.85.05.45.85.5

us-gaap:ReceivablesNetCurrent us-gaap:StatementBusinessSegments

us-gaap:CorporateAndOther


Receivables
Period End2021-06-302020-09-30
Value3.07.0
Percentage of ReceivablesNetCurrent0.72.9
Percentage of Assets0.10.2
Percentage of Assets us-gaap:CorporateAndOther2.63.3

Other Assets Current

us-gaap:OtherAssetsCurrent

us-gaap:OtherAssetsCurrent


Other
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value4951281251131444143383536343935482928455557461582951724835364158716664604434384795
Percentage of OtherAssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.90.84.33.82.00.80.60.60.50.50.50.50.50.50.70.40.30.60.50.40.31.10.30.60.90.60.40.50.60.91.00.90.80.80.60.50.60.82.0

Accumulated Depreciation Depletion And Amortization Property Plant And Equipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment

us-gaap:AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value238462374123673232472282522095205032038320279201622004919928202762013619997199041976719641195341950118582180021682114038109349144884586528462822580057786757473807191641457634617441542304042386136823054
Percentage of AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets442.1452.5458.8559.2501.1418.9305.2308.9309.8312.8345.9282.3287.9261.1265.9276.4276.5272.9276.1283.0251.9211.3207.4130.981.058.759.394.395.297.799.598.699.2106.7106.790.776.854.055.958.660.060.961.264.0

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:PropertyPlantAndEquipmentNet


Property
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value44464284411132223426391652675199509948714656546962335968577255505341514349554789594764917543997912615144831371283938089760272967036669461815836609162897026664562145931565552984127
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets82.481.679.777.575.274.278.478.877.975.680.377.588.577.476.777.174.771.570.069.580.676.293.093.093.492.991.991.591.090.390.789.187.789.486.686.183.882.184.186.188.089.288.086.5

us-gaap:PropertyPlantAndEquipmentNet us-gaap:ConsolidationItems

swn:CorporateAndReconcilingItems


Property
Period End2020-12-312019-12-312018-12-312017-12-31
Value16276095
Percentage of PropertyPlantAndEquipmentNet0.40.51.31.6
Percentage of Assets0.30.41.01.3
Percentage of Assets swn:CorporateAndReconcilingItems12.816.115.58.5

us-gaap:PropertyPlantAndEquipmentNet us-gaap:StatementBusinessSegments

us-gaap:CorporateAndOther


Property
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-30
Value14151821233150566983
Percentage of PropertyPlantAndEquipmentNet0.30.40.60.60.60.61.01.11.31.3
Percentage of Assets0.30.30.40.50.40.50.80.91.01.2
Percentage of Assets us-gaap:CorporateAndOther12.113.68.513.014.313.715.510.332.735.9

Operating Lease Right Of Use Asset

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:OperatingLeaseRightOfUseAsset


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value147155163145153152159164103100
Percentage of OperatingLeaseRightOfUseAsset100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.73.03.23.53.42.92.42.51.61.6

us-gaap:OperatingLeaseRightOfUseAsset us-gaap:BusinessAcquisition

swn:MontageResourcesCorporation


Operating
Period End2020-12-31
Value25
Percentage of OperatingLeaseRightOfUseAsset15.3
Percentage of Assets0.5
Percentage of Assets swn:MontageResourcesCorporation0.0

us-gaap:OperatingLeaseRightOfUseAsset us-gaap:ConsolidationItems

swn:CorporateAndReconcilingItems


Operating
Period End2020-12-312019-12-31
Value7280
Percentage of OperatingLeaseRightOfUseAsset44.250.3
Percentage of Assets1.41.2
Percentage of Assets swn:CorporateAndReconcilingItems57.647.6

us-gaap:OperatingLeaseRightOfUseAsset us-gaap:StatementBusinessSegments

us-gaap:CorporateAndOther


Operating
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value6770747777842925
Percentage of OperatingLeaseRightOfUseAsset45.645.251.050.350.751.228.225.0
Percentage of Assets1.21.31.81.71.51.30.40.4
Percentage of Assets us-gaap:CorporateAndOther57.863.634.947.547.837.09.04.6

Other Assets Noncurrent

us-gaap:OtherAssetsNoncurrent

us-gaap:OtherAssetsNoncurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value355361378322359387771766682688185194242257240176230264249212152143174176190216981241361371061171481189113421029927916312412713878
Percentage of OtherAssetsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets6.66.97.37.77.97.311.511.610.410.73.22.73.43.33.22.43.23.73.53.12.11.72.11.61.41.40.71.41.51.61.31.51.91.71.41.92.83.53.52.31.92.02.31.6

Accounts Payable Current

us-gaap:AccountsPayableCurrent

us-gaap:AccountsPayableCurrent


Accounts
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value653639573416426465525539585626609563642555533502473436473423296346513615578606653690688642507601574553459468484512514487536487473404
Percentage of AccountsPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets12.112.211.110.09.48.87.88.28.99.710.58.09.17.27.17.06.66.16.76.14.04.16.35.74.33.94.47.57.77.66.37.67.58.06.86.66.56.06.56.88.07.77.98.5

Liabilities Current

us-gaap:LiabilitiesCurrent

us-gaap:LiabilitiesCurrent


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value194413701012869875914848880912943846892858732780784821112110646495914787077828409455428888886835688809847731767761885960884766767695693536
Percentage of LiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets36.026.119.620.919.217.312.613.313.914.614.612.612.29.510.410.911.515.615.09.48.05.68.77.36.26.136.49.710.09.98.510.311.110.611.410.811.811.211.210.611.411.011.511.2

Long Term Debt Current

us-gaap:LongTermDebtCurrent

us-gaap:LongTermDebtCurrent


Long
Period End2021-06-302021-03-312019-09-302019-06-302019-03-312018-12-31
Value2072075252520.0
Percentage of LongTermDebtCurrent100.0100.0100.0100.0100.00.0
Percentage of Assets3.83.90.80.80.80.0

us-gaap:LongTermDebtCurrent us-gaap:LongtermDebtType

us-gaap:SeniorNotes


Long
Period End2021-06-302021-03-312019-09-302019-06-302019-03-31
Value207207525252
Percentage of LongTermDebtCurrent100.0100.0100.0100.0100.0
Percentage of Assets3.83.90.80.80.8
Percentage of Assets us-gaap:SeniorNotes0.00.00.00.00.0

Operating Lease Liability Current

us-gaap:OperatingLeaseLiabilityCurrent

us-gaap:OperatingLeaseLiabilityCurrent


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value41414233343234
Percentage of OperatingLeaseLiabilityCurrent100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.80.80.80.80.70.60.5

Other Liabilities Current

us-gaap:OtherLiabilitiesCurrent

us-gaap:OtherLiabilitiesCurrent


Other
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value20542893273174810.0242324422333352055122428371083047261235466624135142117171714151512
Percentage of OtherLiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.40.84.45.04.90.80.10.30.30.30.60.30.50.50.30.70.10.30.30.30.70.20.50.31.50.70.80.80.60.50.20.30.20.20.20.20.20.30.3

Taxes Payable Current

us-gaap:TaxesPayableCurrent

us-gaap:TaxesPayableCurrent


Taxes
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value6267744748525955526258325850625564505947615264496272926966556848804862366148402837365025
Percentage of TaxesPayableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.11.31.41.11.11.00.90.80.81.01.00.50.80.60.80.80.90.70.80.70.80.60.80.50.50.50.60.80.70.70.80.61.10.70.90.50.80.60.50.40.60.60.80.5

Liabilities Noncurrent

us-gaap:LiabilitiesNoncurrent

us-gaap:LiabilitiesNoncurrent


Liabilities
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value3468329136512904285726602623258325512566258939613934478847624766475647975095511862136892512155066446758548353996395937873737356434143103293330583102177217061568145213571265895
Percentage of LiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets64.362.770.869.962.750.439.139.139.039.844.756.155.962.163.366.266.566.772.074.384.280.963.151.347.748.732.443.544.545.046.445.244.744.943.543.241.320.721.621.721.521.421.018.8

Long Term Debt

us-gaap:LongTermDebt

us-gaap:LongTermDebt


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value30203019315024502440227922422271231923192318439144364381463046534652576864434705183818271950191118971703166816961670167013431272121612041094998
Percentage of LongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets56.057.561.058.953.643.233.434.435.436.040.058.461.661.364.365.867.578.275.658.020.721.724.224.224.924.624.824.022.319.517.017.618.019.018.220.9

us-gaap:LongTermDebt us-gaap:CreditFacility, us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:RevolvingCreditFacility, swn:A2018RevolvingCreditFacility, us-gaap:LineOfCredit


Long
Period End2021-06-302021-03-312020-12-312019-12-31
Value56856770034
Percentage of LongTermDebt18.818.822.21.5
Percentage of Assets10.510.813.60.5
Percentage of Assets us-gaap:RevolvingCreditFacility swn:A2018RevolvingCreditFacility us-gaap:LineOfCredit0.00.00.00.0

us-gaap:LongTermDebt us-gaap:DebtInstrument, us-gaap:LongtermDebtType

swn:A2018TermLoanFacility, us-gaap:LineOfCredit


Long
Period End2020-12-312018-12-31
Value7000.0
Percentage of LongTermDebt22.20.0
Percentage of Assets13.60.0
Percentage of Assets swn:A2018TermLoanFacility us-gaap:LineOfCredit0.00.0

swn:FourPointNineFivePercentSeniorNotesDueJanuary2025, us-gaap:SeniorNotes


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value851851851851851858886919
Percentage of LongTermDebt28.228.227.034.734.937.639.539.6
Percentage of Assets15.816.216.520.518.716.313.215.9
Percentage of Assets swn:FourPointNineFivePercentSeniorNotesDueJanuary2025 us-gaap:SeniorNotes0.00.00.00.00.00.00.00.0

swn:FourPointOnePercentSeniorNotesDueMarch2022, us-gaap:SeniorNotes


Long
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value207207206209212212
Percentage of LongTermDebt6.68.48.49.29.59.1
Percentage of Assets4.05.04.54.03.23.7
Percentage of Assets swn:FourPointOnePercentSeniorNotesDueMarch2022 us-gaap:SeniorNotes0.00.00.00.00.00.0

swn:SevenPointFivePercentSeniorNotesDueApril2026, us-gaap:SeniorNotes


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value613613612612612615632642
Percentage of LongTermDebt20.320.319.425.025.127.028.227.7
Percentage of Assets11.411.711.914.713.411.79.411.1
Percentage of Assets swn:SevenPointFivePercentSeniorNotesDueApril2026 us-gaap:SeniorNotes0.00.00.00.00.00.00.00.0

swn:SevenPointSevenFivePercentSeniorNotesDueOctober2027, us-gaap:SeniorNotes


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value436436435435435448478493
Percentage of LongTermDebt14.414.413.817.817.819.721.321.3
Percentage of Assets8.18.38.410.59.58.57.18.5
Percentage of Assets swn:SevenPointSevenFivePercentSeniorNotesDueOctober2027 us-gaap:SeniorNotes0.00.00.00.00.00.00.00.0

us-gaap:LongTermDebt us-gaap:LongtermDebtType

us-gaap:LongTermDebt


Long
Period End2021-06-302021-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value28132812357235704393439143964341436446124651576764424704
Percentage of LongTermDebt93.193.10.00.00.0100.099.199.194.399.1100.0100.0100.0100.0
Percentage of Assets52.253.650.650.757.058.461.060.760.665.267.578.275.658.0
Percentage of Assets us-gaap:LongTermDebt0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Long Term Debt Noncurrent

us-gaap:LongTermDebtNoncurrent

us-gaap:LongTermDebtNoncurrent


Long
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302013-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value2814281231502450244022792242221922672267231835723570439343914396434143644612465157676442472846634539516324661806195016951668166913421271121512021093997
Percentage of LongTermDebtNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets52.253.661.058.953.643.233.433.634.635.240.050.650.757.058.461.060.760.665.267.578.275.658.343.533.633.116.519.724.224.022.219.517.017.618.019.018.220.9

Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent


Pension
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value3340453537404339394346505558584646474951515050484645441717161534343333181620201314181512
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.60.80.90.80.80.80.60.60.60.70.80.70.80.80.80.60.60.70.70.70.70.60.60.40.30.30.30.20.20.20.20.40.50.50.50.30.20.20.30.20.20.30.30.3

Other Liabilities Noncurrent

us-gaap:OtherLiabilitiesNoncurrent

us-gaap:OtherLiabilitiesNoncurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value1621601561242672272193252452562251623093373133243693864344163953983433473393683742602722492392292212351831419491998881757967
Percentage of OtherLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.03.03.03.05.94.33.34.93.74.03.92.34.44.44.24.55.25.46.16.05.44.74.23.22.52.42.52.83.13.03.02.92.93.42.72.01.31.11.31.21.21.21.31.4

Operating Lease Liability Noncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent


Operating
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value104111117107113114119
Percentage of OperatingLeaseLiabilityNoncurrent100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets1.92.12.32.62.52.21.8

Lessee Operating Lease Liability Payments Due Year Two

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value373340423228
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearTwo100.0100.0100.0100.0100.0100.0
Percentage of Assets0.70.50.60.60.50.5

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo us-gaap:PropertyPlantAndEquipmentByType

swn:CompressionRentals


Lessee
Period End2020-12-312019-12-31
Value1413
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearTwo37.839.4
Percentage of Assets0.30.2
Percentage of Assets swn:CompressionRentals0.00.0

swn:OfficeSpaceVehiclesAndEquipment


Lessee
Period End2020-12-312019-12-31
Value2124
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearTwo56.872.7
Percentage of Assets0.40.4
Percentage of Assets swn:OfficeSpaceVehiclesAndEquipment0.00.0

Lessee Operating Lease Liability Payments Due Year Three

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value262231191814
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearThree100.0100.0100.0100.0100.0100.0
Percentage of Assets0.50.30.50.30.30.2

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree us-gaap:PropertyPlantAndEquipmentByType

swn:CompressionRentals


Lessee
Period End2020-12-312019-12-31
Value3.09.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearThree11.540.9
Percentage of Assets0.10.1
Percentage of Assets swn:CompressionRentals0.00.0

Lessee Operating Lease Liability Payments Due Year Four

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value18192110.09.06.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFour100.0100.0100.0100.0100.0100.0
Percentage of Assets0.30.30.30.20.10.1

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour us-gaap:PropertyPlantAndEquipmentByType

swn:CompressionRentals


Lessee
Period End2020-12-312019-12-31
Value1.02.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFour5.610.5
Percentage of Assets0.00.0
Percentage of Assets swn:CompressionRentals0.00.0

swn:OfficeSpaceVehiclesAndEquipment


Lessee
Period End2020-12-312019-12-31
Value1416
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFour77.884.2
Percentage of Assets0.30.2
Percentage of Assets swn:OfficeSpaceVehiclesAndEquipment0.00.0

Lessee Operating Lease Liability Payments Due Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive


Lessee
Period End2020-12-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value1415198.08.05.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFive100.0100.0100.0100.0100.0100.0
Percentage of Assets0.30.20.30.10.10.1

Lessee Operating Lease Liability Payments Due After Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive


Lessee
Period End2020-12-312019-12-31
Value4252
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive100.0100.0
Percentage of Assets0.80.8

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive us-gaap:PropertyPlantAndEquipmentByType

swn:OfficeSpaceVehiclesAndEquipment


Lessee
Period End2020-12-312019-12-31
Value3645
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive85.786.5
Percentage of Assets0.70.7
Percentage of Assets swn:OfficeSpaceVehiclesAndEquipment0.00.0

Operating Lease Liability

us-gaap:OperatingLeaseLiability

us-gaap:OperatingLeaseLiability


Operating
Period End2020-12-312019-12-312019-09-302019-06-302019-03-31
Value159153159103100
Percentage of OperatingLeaseLiability100.0100.0100.0100.0100.0
Percentage of Assets3.12.32.41.61.6

us-gaap:OperatingLeaseLiability us-gaap:BusinessAcquisition

swn:MontageResourcesCorporation


Operating
Period End2020-12-31
Value25
Percentage of OperatingLeaseLiability15.7
Percentage of Assets0.5
Percentage of Assets swn:MontageResourcesCorporation0.0

Lessee Operating Lease Liability Payments Due

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue


Lessee
Period End2020-12-312019-09-302019-06-302019-03-312018-12-31
Value18719011511395
Percentage of LesseeOperatingLeaseLiabilityPaymentsDue100.0100.0100.0100.0100.0
Percentage of Assets3.62.91.81.81.6

Lessee Operating Lease Liability Undiscounted Excess Amount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount


Lessee
Period End2020-12-31
Value28
Percentage of LesseeOperatingLeaseLiabilityUndiscountedExcessAmount100.0
Percentage of Assets0.5

Stockholders Equity

us-gaap:StockholdersEquity

us-gaap:StockholdersEquity


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-312010-12-312009-12-31
Value-18.0586497384823170132463135308229372362220522502193197916521573127891711235731148228244376218705746624293404236223036396929642331
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-0.311.29.69.218.132.248.347.547.145.640.731.232.028.426.322.922.017.813.016.37.813.528.141.446.045.331.246.845.545.045.150.249.348.9

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value-21.0-24.0-24.0-18.0-19.0-19.0-19.0-17.0-18.0-22.0-22.0
Percentage of StockholdersEquity116.7-4.1-4.8-4.7-2.3-1.1-0.6-0.5-0.6-0.7-0.9
Percentage of Assets-0.4-0.5-0.5-0.4-0.4-0.4-0.3-0.3-0.3-0.3-0.4
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value-35.0-38.0-38.0-32.0-33.0-33.0-33.0-31.0-32.0-36.0-36.0-40.0-44.0-44.0-44.0-37.0-38.0-39.0-39.0-39.0-41.0-44.0-48.0-13.013486219-12.0-4.0150408
Percentage of StockholdersEquity194.4-6.5-7.6-8.3-4.0-1.9-1.0-1.0-1.0-1.2-1.5-1.8-2.0-2.0-2.2-2.2-2.4-3.1-4.3-3.5-7.2-3.8-2.1-0.30.20.71.30.4-0.3-0.14.910.3
Percentage of Assets-0.6-0.7-0.7-0.8-0.7-0.6-0.5-0.5-0.5-0.6-0.6-0.6-0.6-0.6-0.6-0.5-0.5-0.5-0.6-0.6-0.6-0.5-0.6-0.10.10.30.40.2-0.1-0.02.25.2
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value5104510250934882473047284726472347204717471547144709470346984698469746874677467334183403340933963384337210191005996969934903
Percentage of StockholdersEquity-28355.6870.61024.71271.4574.7278.0145.6150.7153.1160.6199.6213.8209.3214.5237.4284.4298.6366.7510.0416.1596.5296.4149.476.554.447.821.923.424.626.830.822.8
Percentage of Assets94.697.298.7117.4103.889.670.471.672.173.281.366.866.961.062.565.265.765.166.167.846.340.042.031.725.121.66.811.011.212.013.911.4
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value7.07.07.07.06.06.06.06.06.06.06.06.06.06.05.05.05.05.05.05.04.04.04.04.04.04.04.04.04.04.04.04.0
Percentage of StockholdersEquity-38.91.21.41.80.70.40.20.20.20.20.30.30.30.30.30.30.30.40.50.40.70.30.20.10.10.10.10.10.10.10.10.1
Percentage of Assets0.10.10.10.20.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.00.00.00.00.00.00.00.00.00.10.1
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-312012-12-312011-12-31
Value-4892.0-4283.0-4363.0-4271.0-3678.0-2798.0-1251.0-1361.0-1410.0-1548.0-2142.0-2449.0-2420.0-2471.0-2679.0-3013.0-3090.0-3374.0-3725.0-3515.0-2807.0-2214.0-1082.0105128183633357732653054265319492656
Percentage of StockholdersEquity27177.8-730.9-877.9-1112.2-446.9-164.5-38.5-43.4-45.7-52.7-90.7-111.1-107.6-112.7-135.4-182.4-196.4-264.0-406.2-313.0-489.9-192.9-47.423.745.351.576.776.175.673.264.266.9
Percentage of Assets-90.7-81.6-84.6-102.7-80.7-53.0-18.6-20.6-21.5-24.0-37.0-34.7-34.4-32.0-35.6-41.8-43.2-46.9-52.6-51.0-38.1-26.0-13.39.820.923.324.035.634.433.028.933.6
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock


Stockholders
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302012-12-312011-12-31
Value-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-202.0-181.0-26.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-1.0-2.0
Percentage of StockholdersEquity1122.2-34.5-40.6-52.6-24.5-11.9-6.2-6.4-6.6-6.9-7.7-1.2-0.0-0.0-0.1-0.1-0.1-0.1-0.1-0.1-0.2-0.1-0.0-0.0-0.0-0.0-0.1
Percentage of Assets-3.7-3.8-3.9-4.9-4.4-3.8-3.0-3.1-3.1-3.1-3.1-0.4-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue


Common
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value7000000.07000000.07000000.07000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.06000000.05000000.05000000.05000000.05000000.05000000.05000000.04000000.04000000.04000000.04000000.04000000.04000000.04000000.04000000.04000000.03531000.03529000.03517000.03515000.03516000.03511000.03504000.03492000.03492000.03491000.03483000.03481000.03480000.03477000.03461000.0
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.10.10.10.20.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.10.00.00.00.00.00.00.00.00.00.00.00.00.10.10.00.00.00.00.00.10.10.10.1

Additional Paid In Capital Common Stock

us-gaap:AdditionalPaidInCapitalCommonStock

us-gaap:AdditionalPaidInCapitalCommonStock


Additional
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value5104510250934882473047284726472347204717471547144709470346984698469746874677467334183403340933963384337210191005996985970960952946934928916911903880874870862833
Percentage of AdditionalPaidInCapitalCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets94.697.298.7117.4103.889.670.471.672.173.281.366.866.961.062.565.265.765.166.167.846.340.042.031.725.121.66.811.011.211.712.112.212.513.713.913.112.210.711.412.213.013.714.317.5

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:RetainedEarningsAccumulatedDeficit


Retained
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value-4892.0-4283.0-4363.0-4271.0-3678.0-2798.0-1251.0-1361.0-1410.0-1548.0-2142.0-2449.0-2420.0-2471.0-2679.0-3013.0-3090.0-3374.0-3725.0-3515.0-2807.0-2214.0-1082.0105128183633357732653054284626522508232220761949213122752763265624972322215520181414
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-90.7-81.6-84.6-102.7-80.7-53.0-18.6-20.6-21.5-24.0-37.0-34.7-34.4-32.0-35.6-41.8-43.2-46.9-52.6-51.0-38.1-26.0-13.39.820.923.324.035.634.433.833.031.830.430.028.930.130.332.333.634.634.434.033.529.6

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax


Accumulated
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value-35.0-38.0-38.0-32.0-33.0-33.0-33.0-31.0-32.0-36.0-36.0-40.0-44.0-44.0-44.0-37.0-38.0-39.0-39.0-39.0-41.0-44.0-48.0-13.013486219-12.0-34.967-4.342489555149192321474408229108598384
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-0.6-0.7-0.7-0.8-0.7-0.6-0.5-0.5-0.5-0.6-0.6-0.6-0.6-0.6-0.6-0.5-0.5-0.5-0.6-0.6-0.6-0.5-0.6-0.10.10.30.40.2-0.1-0.4-0.10.61.30.82.22.74.35.65.23.21.60.91.41.8

Treasury Stock Value

us-gaap:TreasuryStockValue

us-gaap:TreasuryStockValue


Treasury
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value202202202202202202202202202202181261.01.01.01.01.01.01.01.01.01.01.01.01.00.3630.3340.5070.50.4921.5321.592.3152.2952.2282.7862.7682.7483.4444.333
Percentage of TreasuryStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.73.83.94.94.43.83.03.13.13.13.10.40.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.10.1

Stock Issued During Period Value New Issues

us-gaap:StockIssuedDuringPeriodValueNewIssues

us-gaap:StockIssuedDuringPeriodValueNewIssues


Stock
Period End2020-09-302016-12-312015-12-312015-09-302015-06-302015-03-31
Value1520.00.00.00.0669
Percentage of StockIssuedDuringPeriodValueNewIssues100.00.00.00.00.0100.0
Percentage of Assets0.00.00.00.00.00.0

us-gaap:StockIssuedDuringPeriodValueNewIssues us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital


Stock
Period End2020-09-302016-12-312015-12-312015-09-302015-06-302015-03-31
Value1510.00.00.00.0669
Percentage of StockIssuedDuringPeriodValueNewIssues99.30.00.00.00.0100.0
Percentage of Assets0.00.00.00.00.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.0

us-gaap:CommonStock


Stock
Period End2020-09-302016-12-31
Value1.00.0
Percentage of StockIssuedDuringPeriodValueNewIssues0.70.0
Percentage of Assets0.00.0
Percentage of Assets us-gaap:CommonStock0.00.0

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

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue


Adjustments
Period End2021-06-302020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value2.01.01.01.03.03.03.03.05.06.07.09.09.010.010.08.08.01626
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital


Adjustments
Period End2021-06-302020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value2.01.01.01.03.03.03.03.05.06.07.09.09.010.010.08.08.01626
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value27034712115394160225196101442252307300364308211266312161505372461355392444439443460396427406391417
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax25.732.415.529.022.927.030.230.815.144.621.432.336.839.638.128.632.836.923.558.650.759.751.865.567.759.157.860.258.663.859.566.462.5

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-265.0-227.0-183.0-228.0-242.0-228.0-210.0-275.0-302.0-258.01354-320.0-381.0-294.0-331.0-315.0-272.0-334.0-205.0-680.302-481.162-362.252-442.612-546.603-555.21-538.466-501.676-469.19-515.458-211.123-519.354-553.681-441.473
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-25.2-21.2-23.5-43.3-59.0-38.5-28.2-43.2-45.3-26.1115.2-33.6-46.7-32.0-40.9-42.7-33.5-39.5-30.0-78.9-65.6-46.9-64.5-91.1-84.6-72.4-65.4-61.3-76.2-31.5-76.1-93.9-66.1

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-7.0-129.0-20.016015368-39.0-47.0-10.0-19.0-1414.0-15.0-840.0-28.0-50.0-18.0-265.0-19.0-7.018272-64.00264-10.807301101584.526120-214.21911316224
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.7-12.0-2.630.437.311.5-5.2-7.4-1.5-1.9-120.3-1.6-102.9-3.0-6.2-2.4-32.7-2.2-1.021.29.9-8.39.4-1.845.913.67.60.617.8-32.016.727.53.7

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

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-2.0-9.0-82.0855.00.0-24.0-126.0-211.0165192-28.0-921.042
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.2-0.8-10.516.11.20.0-3.2-19.8-31.616.716.3-2.9-112.94.6

Amortization Of Financing Costs

us-gaap:AmortizationOfFinancingCosts

us-gaap:AmortizationOfFinancingCosts


Amortization
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-30
Value2.02.03.02.03.01.03.03.01.01.02.02.02.02.02.03.02.02.02.08.02.02.03.01.03.0467.01.01.01.01.01.0
Percentage of AmortizationOfFinancingCosts100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Income Tax Expense Benefit

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DeferredIncomeTaxExpenseBenefit


Deferred
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1.00.00.0408-9.01115-426.00.00.00.00.0-67.0-4.0-2.0-20.0-1.01.0-464.0-1088.0-500.04912910813712912414014784-141.097-85.856-305.4257099111108888610875109
Percentage of DeferredIncomeTaxExpenseBenefit100.00.00.0100.0100.0100.0100.0100.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Depreciation Depletion And Amortization

us-gaap:DepreciationDepletionAndAmortization

us-gaap:DepreciationDepletionAndAmortization


Depreciation
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value100969070841131191251211121241511421431401351231068799107143215274310293249238228226215204186179208200207193190179171164157151144139
Percentage of DepreciationDepletionAndAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DepreciationDepletionAndAmortization us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Depreciation
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value97946881111123118110140126117120107
Percentage of DepreciationDepletionAndAmortization97.097.997.196.498.298.497.598.292.788.781.888.987.0

swn:Marketing


Depreciation
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value3.02.02.03.02.02.03.0
Percentage of DepreciationDepletionAndAmortization3.02.12.93.61.81.62.5

Increase Decrease In Accounts Payable

us-gaap:IncreaseDecreaseInAccountsPayable

us-gaap:IncreaseDecreaseInAccountsPayable


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value4233-2.0-8.0-35.0-86.0-17.05.0-81.0-48.05.07.070-17.0321415-13.03.067-15.0-124.0-23.0-33.013-35.032-1.0-41.3469429-3.004407.31252-9.701-6.2614.9129.9518.9192.967-10.347401617-8.078
Percentage of IncreaseDecreaseInAccountsPayable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Increase Decrease In Accounts Receivable

us-gaap:IncreaseDecreaseInAccountsReceivable

us-gaap:IncreaseDecreaseInAccountsReceivable


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value7.03356-12.0-41.0-53.023-36.0-32.0-189.01461934-46.0689.041-53.0833911-103.0-28.0-13.0-124.0-38.073-56.0-29.1547819-1.239589.6897925-26.562-42.604-14.323-10.1922.87311-54.175-3.157-24.698-6.458
Percentage of IncreaseDecreaseInAccountsReceivable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Increase Decrease In Inventories

us-gaap:IncreaseDecreaseInInventories

us-gaap:IncreaseDecreaseInInventories


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302017-12-312017-09-302015-12-312015-03-312014-12-312014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value6.0-9.01.03.02.0-8.05.06.01.0-5.04.02.00.0-1.0-2.03.01.0-0.564-7.5987.2274.2781.944-1.503-8.52-4.753-3.33518-12.754-1.8648.625-3.058-6.6763.60311
Percentage of IncreaseDecreaseInInventories100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Increase Decrease In Other Operating Capital Net

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value25-1.018-17.0-12.0-9.0-25.0171411-47.0322.07.01211-11.0144.0-11.0-15.0-3.085-69.00.0-26.01.7462.25448-18.469-20.676-16.037-38.453-2.1358.5712-16.999-3.8790.9586.54410-4.661146.628
Percentage of IncreaseDecreaseInOtherOperatingCapitalNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value27034712115394160225196101442252307300364308211266312161505372461355392444439443460396427406391417
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax25.732.415.529.022.927.030.230.815.144.621.432.336.839.638.128.632.836.923.558.650.759.751.865.567.759.157.860.258.663.859.566.462.5

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312009-09-302009-06-302009-03-31
Value-609.080-92.0-593.0-880.0-1547.011049138594307-29.05120833477284351-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078312211207194144186246128158175167136149160122171157118121-432.83
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 RevenueFromContractWithCustomerExcludingAssessedTax-58.07.5-11.8-112.5-214.6-261.314.87.720.760.026.1-3.06.222.641.310.435.041.5-30.7-108.8-113.6-195.5-306.7-232.2-103.18.432.422.720.017.415.921.428.517.421.322.821.920.222.323.620.725.725.323.525.4-80.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome


Net
Period End2020-12-312020-09-302019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312017-09-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value4.01.0-13.01.04.00.06.00.01.0-41.0-29.0-33.0-25.029-27.95926-26.431
Percentage of NetIncomeLoss-4.3-0.2-11.82.02.90.02.00.01.31.91.74.2-32.19.3-13.312.7-13.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.50.2-1.70.20.60.00.50.00.1-6.0-3.9-4.3-2.73.0-3.02.5-2.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:StatementEquityComponents

us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome, us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCredit


Net
Period End2020-09-302019-09-302019-06-302019-03-31
Value1.01.04.00.0
Percentage of NetIncomeLoss-0.22.02.90.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.20.20.60.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncome us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCredit0.00.00.00.0

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings


Net
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-30
Value-609.080-593.0-880.0-1547.049138594307-29.05120833477284351-210.0-708.0-593.0-1132.0-2107.0-1739.0-788.078312211
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-58.07.5-112.5-214.6-261.37.720.760.026.1-3.06.222.641.310.435.041.5-30.7-108.8-113.6-195.5-306.7-232.2-103.18.432.422.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Share Based Compensation

us-gaap:ShareBasedCompensation

us-gaap:ShareBasedCompensation


Share
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value2.01.00.01.01.02.02.02.02.02.03.05.04.05.07.06.06.09.08.06.06.06.05.04.04.514.494.3872.9212.9682.9943.5692.6772.7052.8443.9311.9332.2362.453.2082.1792.1362.297
Percentage of ShareBasedCompensation100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-265.0-227.0-183.0-228.0-242.0-228.0-210.0-275.0-302.0-258.01354-320.0-381.0-294.0-331.0-315.0-272.0-334.0-205.0-680.302-481.162-362.252-442.612-546.603-555.21-538.466-501.676-469.19-515.458-211.123-519.354-553.681-441.473
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-25.2-21.2-23.5-43.3-59.0-38.5-28.2-43.2-45.3-26.1115.2-33.6-46.7-32.0-40.9-42.7-33.5-39.5-30.0-78.9-65.6-46.9-64.5-91.1-84.6-72.4-65.4-61.3-76.2-31.5-76.1-93.9-66.1

Payments To Acquire Property Plant And Equipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value2592661942232452372072403683252092984033383473313252902721807412238346841511715610574721541480542695518
Percentage of PaymentsToAcquirePropertyPlantAndEquipment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Payments
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value2592662232452372393673252953963343273203182832511797312037846138910305548531676499
Percentage of PaymentsToAcquirePropertyPlantAndEquipment100.0100.0100.0100.0100.099.699.7100.099.098.398.894.296.797.897.692.399.498.698.498.798.593.788.098.992.593.892.1

Payments To Acquire Productive Assets

us-gaap:PaymentsToAcquireProductiveAssets

us-gaap:PaymentsToAcquireProductiveAssets


Payments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value26622719622824422822229132825828232438230232532427934020215045196406418466508330569610533525551692483484483583557640518498526567520543442
Percentage of PaymentsToAcquireProductiveAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities


Net
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-7.0-129.0-20.016015368-39.0-47.0-10.0-19.0-1414.0-15.0-840.0-28.0-50.0-18.0-265.0-19.0-7.018272-64.00264-10.807301101584.526120-214.21911316224
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.7-12.0-2.630.437.311.5-5.2-7.4-1.5-1.9-120.3-1.6-102.9-3.0-6.2-2.4-32.7-2.2-1.021.29.9-8.39.4-1.845.913.67.60.617.8-32.016.727.53.7

Proceeds From Issuance Of Long Term Debt

us-gaap:ProceedsFromIssuanceOfLongTermDebt us-gaap:BusinessAcquisition, us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:ProceedsFromIssuanceOfLongTermDebt

swn:MontageResourcesCorporation, swn:EightPointThreeSevenFivePercentSeniorNotesDueSeptember2028, us-gaap:SeniorNotes


Proceeds
Period End2020-08-31
Value345
Percentage of ProceedsFromIssuanceOfLongTermDebt100.0

us-gaap:ProceedsFromIssuanceOfLongTermDebt us-gaap:DebtInstrument, us-gaap:LongtermDebtType

swn:EightPointThreeSevenFivePercentSeniorNotesDueSeptember2028, us-gaap:SeniorNotes


Proceeds
Period End2020-08-31
Value345
Percentage of ProceedsFromIssuanceOfLongTermDebt100.0

Effective Income Tax Rate Continuing Operations

us-gaap:EffectiveIncomeTaxRateContinuingOperations

us-gaap:EffectiveIncomeTaxRateContinuingOperations


Effective
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-31
Value001.000-0.360.190.180.1-2.540000-0.08-0.210000.0300
Percentage of EffectiveIncomeTaxRateContinuingOperations0.00.0100.00.00.0100.0100.0100.0100.0100.00.00.00.00.0100.0100.00.00.00.0100.00.00.0

Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-312007-12-31
Value3850000.04635000.05178000.06020000.05416000.03779000.03813000.03843000.03622000.03022000.03070000.03085200.03312700.02913800.03148500.03182200.03649500.03271000.04490300.04540600.04741700.04201900.04369500.04471900.04769100.05649200.07396500.08552900.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap:AwardType

us-gaap:EmployeeStockOption


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312014-12-312013-12-312012-12-31
Value3699000.03789000.03850000.04278000.04478000.04573000.04635000.05102000.05106000.05120000.05178000.05948000.06010000.06017000.06020000.06295000.06284000.06721000.05416000.05716000.05750000.05769000.05623000.03622000.03312700.03650000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber0.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.00.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber us-gaap:ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRange

swn:RangeOfExercisePricesOne


Share
Period End2020-12-312019-12-31
Value3126000.03467000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber81.274.8

swn:RangeOfExercisePricesTwo


Share
Period End2020-12-312019-12-31
Value634000.0644000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber16.513.9

Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice


Share
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-312011-12-312010-12-31
Value13.3915.2617.0619.4323.4634.8234.8434.8935.4136.2736.2635.8135.729.8421.2416.13
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice us-gaap:AwardType

us-gaap:EmployeeStockOption


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312014-12-312013-12-312012-12-31
Value12.6313.4313.3915.9515.4815.2715.2617.0217.0417.0717.0619.3419.3919.4219.4320.1621.0920.4823.4624.124.0724.1324.5735.4135.729.84
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice0.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.00.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice us-gaap:ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRange

swn:RangeOfExercisePricesOne


Share
Period End2020-12-312019-12-31
Value8.958.63
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice66.856.6

swn:RangeOfExercisePricesTwo


Share
Period End2020-12-312019-12-31
Value30.5930.6
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice228.5200.5

Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod

us-gaap:RestrictedStock


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value297000.010000.014000.063000.0495000.012000.016000.0462000.06000.09000.06000.031000.0308000.05000.019000.0133000.0354000.04549000.02000.02000.0077000.05719000.04000.02000.097000.01270000.03000.018560.03440.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Tax Assets Valuation Allowance

us-gaap:DeferredTaxAssetsValuationAllowance

us-gaap:DeferredTaxAssetsValuationAllowance


Deferred
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value15398760973214764935.0
Percentage of DeferredTaxAssetsValuationAllowance100.0100.0100.0100.0100.0100.0100.0

swn:AllocatedShareBasedCompensationExpenseLiabilityBased

swn:AllocatedShareBasedCompensationExpenseLiabilityBased


Allocated
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value7.0132.05.0-1.0-1.02.05.04.03.01.0
Percentage of AllocatedShareBasedCompensationExpenseLiabilityBased100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:DerivativeAmortizationOfPremiumPaid us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk

swn:DerivativeAmortizationOfPremiumPaid

srt:NaturalGasReserves, swn:FixedPriceSwaps


Derivative
Period End2020-12-312020-09-302020-06-30
Value1000000.04000000.04000000.0
Percentage of DerivativeAmortizationOfPremiumPaid100.0100.0100.0

srt:NaturalGasReserves, us-gaap:PutOption


Derivative
Period End2021-06-302021-03-31
Value02000000.0
Percentage of DerivativeAmortizationOfPremiumPaid0.00.0

swn:DerivativeGainLossOnDerivativeSettledNet

swn:DerivativeGainLossOnDerivativeSettledNet


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-99.0-22.0529712093688834-10.0-99.0-6.020-9.02317-39.0-30.014-10.0237.067495135
Percentage of DerivativeGainLossOnDerivativeSettledNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:DerivativeGainLossOnDerivativeSettledNet us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk

srt:NaturalGasReserves, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value-6.05.0-8.061845.0254514-6.0-50.05.0130.09.07.0
Percentage of DerivativeGainLossOnDerivativeSettledNet6.1-22.7-15.462.970.05.436.851.141.260.050.5-83.365.0-0.039.141.2

srt:NaturalGasReserves, swn:PurchasedFixedPriceSwaps


Derivative
Period End2021-06-302020-09-302020-06-302020-03-312019-06-302019-03-31
Value1.0-2.0-1.0-1.00.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet-1.0-2.1-0.8-1.10.0-0.0

srt:NaturalGasReserves, swn:ThreeWayCostlessCollars


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value-8.01.0-5.00.07.03612158.0-4.0-33.05.0127.03.01.0
Percentage of DerivativeGainLossOnDerivativeSettledNet8.1-4.5-9.60.05.838.717.617.023.540.033.3-83.360.0-77.813.05.9

srt:NaturalGasReserves, swn:TwoWayCostlessCollars


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-2.02.0-6.0-5.00.06.04.010.03.0-1.0-5.00.00.04.0
Percentage of DerivativeGainLossOnDerivativeSettledNet2.0-9.1-11.5-5.20.06.55.911.48.810.05.1-0.00.0-44.4

srt:NaturalGasReserves, us-gaap:BasisSwap


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value8.0414720-7.0168.0-3.0-4.0-4.0-3.0-4.0-3.0-21.0
Percentage of DerivativeGainLossOnDerivativeSettledNet-8.1-186.490.420.6-5.817.211.8-3.4-11.840.03.066.7-15.0233.3

srt:NaturalGasReserves, us-gaap:PutOption


Derivative
Period End2021-06-302021-03-31
Value0.0-2.0
Percentage of DerivativeGainLossOnDerivativeSettledNet-0.09.1

srt:OilReserves, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-28.0-17.02117229.03.03.02.02.00.00.00.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet28.377.340.417.518.39.74.43.45.9-20.0-0.0-0.00.0-0.0

srt:OilReserves, swn:ThreeWayCostlessCollars


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-06-302019-03-31
Value-5.0-1.04.01.03.01.00.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet5.14.57.71.02.51.10.0-0.0

srt:OilReserves, swn:TwoWayCostlessCollars


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-1.0-1.04.04.06.03.02.02.01.01.00.00.00.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet1.04.57.74.15.03.22.92.32.9-10.0-0.0-0.00.0-0.0

swn:Ethane, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-6.0-4.00.0-2.01.06.05.06.05.01.0-2.0-6.00.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet6.118.20.0-2.10.86.57.46.814.7-10.02.0100.00.0-0.0

swn:NaturalGasoline, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-31
Value-13.0-9.0
Percentage of DerivativeGainLossOnDerivativeSettledNet13.140.9

swn:NormalButane, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-31
Value-9.0-7.0
Percentage of DerivativeGainLossOnDerivativeSettledNet9.131.8

swn:Propane, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-30.0-30.0-1.02.07.010.09.0117.02.00.0-5.0-1.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet30.3136.4-1.92.15.810.813.212.520.6-20.0-0.083.3-5.0-0.0

swn:Propane, swn:TwoWayCostlessCollars


Derivative
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value0.00.01.01.01.01.00.00.00.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet0.00.00.81.11.51.10.0-0.0-0.0-0.0

us-gaap:NaturalGasStorage, swn:StorageFixedPriceSwap


Derivative
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value1.00.01.0-1.00.00.0
Percentage of DerivativeGainLossOnDerivativeSettledNet1.00.01.1-1.10.0-0.0

swn:DerivativeGainLossOnDerivativeUnsettledNet

swn:DerivativeGainLossOnDerivativeUnsettledNet


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-772.0-169.0134-289.0-229.0246-14.012118-22.089-59.0-56.02.010131173146-325.081-108.0-21.0-50.0-34.0-50.0-21.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:DerivativeGainLossOnDerivativeUnsettledNet us-gaap:DerivativeInstrumentRisk

us-gaap:InterestRateSwap


Derivative
Period End2021-06-302021-03-312020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value0.01.01.0-1.00.01.0-2.00.0-1.01.00.02.01.01.0-1.01.05.00.00.0-3.00.0-1.02.0-3.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet-0.0-0.6-0.4-0.4-0.08.3-1.7-0.0-1.1-1.7-0.0100.01.03.2-0.60.7-1.50.0-0.014.3-0.02.9-4.014.3

swn:DerivativeGainLossOnDerivativeUnsettledNet us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk

srt:NaturalGasReserves, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value-221.0-22.049-138.0-39.010310.0-19.057-2.019-17.0-26.0-3.058-2.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet28.613.036.647.817.041.9-71.4-158.348.39.121.328.846.4-150.057.4-6.5

srt:NaturalGasReserves, swn:PurchasedFixedPriceSwaps


Derivative
Period End2021-06-302020-09-302020-06-302020-03-312019-06-302019-03-31
Value2.04.01.0-1.00.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet-0.3-1.4-0.4-0.40.0-0.0

srt:NaturalGasReserves, swn:ThreeWayCostlessCollars


Derivative
Period End2021-06-302020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value-249.0117-98.0-45.0-51.010.03.0222.0-12.0-7.0-24.0-5.049-1.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet32.387.333.919.7-20.7-71.425.018.6-9.1-13.511.942.9-250.048.5-3.2

srt:NaturalGasReserves, swn:TwoWayCostlessCollars


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-30
Value-148.0-12.055-34.0-7.0-4.04.0-11.010.0-1.0-4.02.0-1.03.04.03.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet19.27.141.011.83.1-1.6-28.6-91.78.54.5-4.5-3.41.8150.04.09.7

srt:NaturalGasReserves, us-gaap:BasisSwap


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value443.01954-13.0-1.011124.0-10.0-1.0-5.0-4.020
Percentage of DerivativeGainLossOnDerivativeUnsettledNet-5.7-1.814.2-18.75.7-0.4-78.6100.03.445.5-1.18.57.11000.0

srt:NaturalGasReserves, us-gaap:CallOption


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-30
Value-40.03.015-16.0-4.0-5.0-4.01.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet5.2-1.811.25.51.7-2.028.68.3

srt:NaturalGasReserves, us-gaap:PutOption


Derivative
Period End2021-06-30
Value1.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet-0.1

srt:NaturalGasReserves, us-gaap:Swaption


Derivative
Period End2021-06-302021-03-31
Value-4.01.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet0.5-0.6

srt:OilReserves, swn:FixedPriceSwaps


Derivative
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
Value-41.0-40.0-20.0-46.0118-22.08.05.0-13.0190.00.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet5.323.76.920.148.0157.166.74.259.121.3-0.0-0.00.0

srt:OilReserves, swn:ThreeWayCostlessCollars


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value-29.0-18.0-12.0-4.0-6.025-6.03.01.00.00.00.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet3.810.7-9.01.42.610.242.925.00.8-0.00.0-0.0-0.0

srt:OilReserves, swn:TwoWayCostlessCollars


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value0.0-1.0-5.0-5.0-10.019-7.00.04.0-7.010.00.00.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet-0.00.6-3.71.74.47.750.00.03.431.811.2-0.0-0.00.0

srt:OilReserves, us-gaap:CallOption


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.0-1.00.00.00.01.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet-0.00.60.0-0.0-0.00.4

swn:Ethane, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-11.0-2.02.0-13.0-22.012-2.01.00.07.034-27.0-2.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet1.41.21.54.59.64.914.38.30.0-31.838.245.83.60.0

swn:Ethane, swn:TwoWayCostlessCollars


Derivative
Period End2021-06-30
Value-1.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet0.1

swn:NaturalGasoline, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-31
Value-11.0-20.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet1.411.8

swn:NormalButane, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-31
Value-19.0-15.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet2.58.9

swn:Propane, swn:FixedPriceSwaps


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value-43.0-45.0-35.0-17.0-44.036-6.010.013-4.030-10.0-12.03.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet5.626.6-26.15.919.214.642.983.311.018.233.716.921.4150.0

swn:Propane, swn:TwoWayCostlessCollars


Derivative
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value1.0-1.0-3.02.0-1.01.02.00.00.00.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet0.70.31.30.87.18.31.7-0.00.0-0.0-0.0

us-gaap:NaturalGasStorage, swn:PurchasedFixedPriceSwaps


Derivative
Period End2021-06-302020-09-302020-06-302020-03-312019-06-30
Value1.01.00.0-1.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet-0.1-0.3-0.0-0.40.0

us-gaap:NaturalGasStorage, swn:StorageFixedPriceSwap


Derivative
Period End2021-06-302020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value-2.0-2.01.0-1.02.0-1.00.0
Percentage of DerivativeGainLossOnDerivativeUnsettledNet0.30.7-0.4-0.416.7-0.8-0.0

swn:DerivativePremiumPaid us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

swn:DerivativePremiumPaid

srt:NaturalGasReserves, swn:DerivativeAssets, swn:FixedPriceSwaps, us-gaap:Nondesignated


Derivative
Period End2020-09-302020-06-302020-03-312019-12-31
Value-4.0-4.09.00.0
Percentage of DerivativePremiumPaid100.0100.0100.00.0

swn:DerivativePremiumPaid us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk

srt:NaturalGasReserves, swn:FixedPriceSwaps


Derivative
Period End2020-09-302020-06-302020-03-312019-12-31
Value-4.0-4.09.00.0
Percentage of DerivativePremiumPaid100.0100.0100.00.0

swn:FullCostCeilingTestPriceperBarrel us-gaap:ReserveQuantitiesByTypeOfReserve

swn:FullCostCeilingTestPriceperBarrel

srt:NaturalGasLiquidsReserves


Full
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value3.4913.570.39-1.099.96-3.76-1.317.65
Percentage of FullCostCeilingTestPriceperBarrel100.0100.0100.0100.0100.0100.0100.0100.0

srt:OilReserves


Full
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value9.7740.01-3.77-8.655.77-3.62-1.6163.0
Percentage of FullCostCeilingTestPriceperBarrel279.9294.8-966.7789.0559.996.3123.8356.9

swn:FullCostCeilingTestPriceperMillionBritishThermalUnits us-gaap:ReserveQuantitiesByTypeOfReserve

swn:FullCostCeilingTestPriceperMillionBritishThermalUnits

srt:NaturalGasReserves


Full
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value0.272.16-0.1-0.232.3-0.15-0.053.07
Percentage of FullCostCeilingTestPriceperMillionBritishThermalUnits100.0100.0100.0100.0100.0100.0100.0100.0

swn:IncreaseDecreaseInAccruedExpendituresBetweenPeriods

swn:IncreaseDecreaseInAccruedExpendituresBetweenPeriods


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-9.038-4.0-7.00.08.0-18.0-53.03966-74.0-31.0193313-2.041-52.0-19.02727-78.0-28.06.0-11.0269-53.0-56.0-5.6-0.9147.532-3.8560.2151.360561.59.6292.327
Percentage of IncreaseDecreaseInAccruedExpendituresBetweenPeriods100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:LiabilityBasedShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount

swn:LiabilityBasedShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount


Liability
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value5000000.05000000.01000000.01000000.0001000000.03000000.01000000.03000000.00
Percentage of LiabilityBasedShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount100.0100.0100.0100.00.00.0100.0100.0100.0100.00.0

swn:ShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount

swn:ShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount


Share
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value1000000.0001000000.01000000.01000000.03000000.04000000.03000000.02000000.04000000.04000000.0
Percentage of ShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeitedInPeriod us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeitedInPeriod

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value1093000.01615000.0862000.0278000.0316000.0135000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeitedInPeriod100.0100.0100.0100.0100.0100.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value0622000.0176000.02124000.0000119000.054000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeitedInPeriod0.038.563.3672.20.00.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value73000.0416000.0231000.01365000.01464000.0261000.0235000.0504000.0463000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeitedInPeriod6.725.883.1432.01084.40.00.00.00.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeituresInPeriodWeightedAverageFairValue us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeituresInPeriodWeightedAverageFairValue

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value01.00001.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeituresInPeriodWeightedAverageFairValue0.0100.00.00.00.0100.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value02.98-0.043.10004.65-0.03
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeituresInPeriodWeightedAverageFairValue0.0298.00.00.00.00.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value0.064.31-0.03-0.111.67-0.62-0.723.850.02
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsForfeituresInPeriodWeightedAverageFairValue0.0431.00.00.0167.00.00.00.00.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriod us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriod

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value0.0180.00.00.020
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriod0.0100.00.00.00.0100.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value0.03.580.00.06.1720.00.02.7570.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriod0.019.30.00.030.80.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value0.01.4860.00.06.1720.00.08.6590.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriod0.08.00.00.030.80.00.00.00.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageFairValue us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageFairValue

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value01.00001.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageFairValue0.0100.00.00.00.0100.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value04.14001.41004.340
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageFairValue0.0414.00.00.0141.00.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value04.23001.41004.340
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageFairValue0.0423.00.00.0141.00.00.00.00.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriod us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriod

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value54000.04319000.00100000.000
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriod100.0100.00.0100.00.00.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-06-302020-03-312019-09-302019-06-302019-03-31
Value02020000.000000
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriod0.046.80.00.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value04522000.0094000.03852000.07000.0497000.02120000.052000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriod0.0104.70.00.00.00.00.00.00.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageFairValue us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageFairValue

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-31
Value01.001.000
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageFairValue0.0100.00.0100.00.00.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-06-302020-03-312019-09-302019-06-302019-03-31
Value04.0500000
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageFairValue0.0405.00.00.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-30
Value03.400.041.380-0.24.291.45
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageFairValue0.0340.00.00.00.00.00.00.00.0

us-gaap:AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation

us-gaap:AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation


Adjustments
Period End2021-03-312020-06-302019-03-312018-12-312018-06-302018-03-312017-12-312016-12-312016-09-302016-06-302016-03-31
Value3000000.01000000.01000000.02000000.001000000.01000000.04000000.0-1000000.01000000.05000000.0
Percentage of AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0

us-gaap:AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital


Adjustments
Period End2021-03-312020-06-302019-03-312018-12-312018-06-302018-03-312017-12-312016-12-312016-09-302016-06-302016-03-31
Value3000000.01000000.01000000.02000000.001000000.01000000.04000000.0-1000000.01000000.05000000.0
Percentage of AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetImpairmentCharges

us-gaap:AssetImpairmentCharges


Asset
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value33536165514798.02.06.00.010.0161
Percentage of AssetImpairmentCharges100.0100.0100.0100.0100.0100.0100.00.0100.0100.0

us-gaap:AssetImpairmentCharges us-gaap:PropertyPlantAndEquipmentByType

swn:OtherNonCoreAssets


Asset
Period End2020-12-312020-09-302020-06-302018-12-312018-09-30
Value0.00.05.010.01.0
Percentage of AssetImpairmentCharges0.00.00.8100.00.6

us-gaap:AssetImpairmentCharges us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Asset
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302018-09-30
Value36165514790.06.015
Percentage of AssetImpairmentCharges100.0100.0100.00.0100.09.3

us-gaap:BusinessCombinationAcquisitionRelatedCosts

us-gaap:BusinessCombinationAcquisitionRelatedCosts


Business
Period End2021-06-302021-03-312020-12-312020-09-30
Value3.01.0383.0
Percentage of BusinessCombinationAcquisitionRelatedCosts100.0100.0100.0100.0

us-gaap:BusinessCombinationAcquisitionRelatedCosts us-gaap:BusinessAcquisition

swn:IndigoNaturalResourcesLLC


Business
Period End2021-06-30
Value2.0
Percentage of BusinessCombinationAcquisitionRelatedCosts66.7

swn:MontageResourcesCorporation


Business
Period End2020-12-312020-09-30
Value383.0
Percentage of BusinessCombinationAcquisitionRelatedCosts100.0100.0

us-gaap:BusinessCombinationAcquisitionRelatedCosts us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Business
Period End2021-06-302021-03-312020-09-30
Value3.01.03.0
Percentage of BusinessCombinationAcquisitionRelatedCosts100.0100.0100.0

us-gaap:BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable

swn:IndigoNaturalResourcesLLC


Business
Period End2021-05-28
Value1600
Percentage of BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable100.0

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value213
Percentage of BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable0.0

us-gaap:BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual

swn:MontageResourcesCorporation


Business
Period End2021-06-302021-03-312020-12-31
Value606128
Percentage of BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual100.0100.0100.0

us-gaap:BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual

swn:MontageResourcesCorporation


Business
Period End2021-06-302021-03-312020-12-31
Value12013063
Percentage of BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual100.0100.0100.0

us-gaap:CurrentIncomeTaxExpenseBenefit

us-gaap:CurrentIncomeTaxExpenseBenefit


Current
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302015-12-312015-09-302015-06-302014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.00.00.0-2.0-1.0-1.00.00.01.00.00.00.0-12.0-10.0-9.00.07.0-13.0323.0-0.52-11.473-16.068160.136180.1010.10.1680.5073.4910.10.114-5.2742.70.0
Percentage of CurrentIncomeTaxExpenseBenefit0.00.00.0100.0100.0100.00.00.0100.00.00.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

us-gaap:DebtInstrumentInterestRateDuringPeriod us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:DebtInstrumentInterestRateDuringPeriod

swn:A2018RevolvingCreditFacility, us-gaap:LineOfCredit


Debt
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value0.012.091.5814-0.00260.0212-0.0046-0.000430.03923
Percentage of DebtInstrumentInterestRateDuringPeriod100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312016-09-302016-06-30
Value0-1000000.000-1000000.000-1000000.0-1000000.0-1000000.000-1000000.00-1000000.00-1000000.0
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses0.0100.00.00.0100.00.00.0100.0100.0100.00.00.0100.00.0100.00.0100.0

us-gaap:DefinedBenefitPlanBenefitObligationIncreaseDecreaseForRemeasurementDueToSettlement us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanBenefitObligationIncreaseDecreaseForRemeasurementDueToSettlement

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-30
Value3000000.0
Percentage of DefinedBenefitPlanBenefitObligationIncreaseDecreaseForRemeasurementDueToSettlement100.0

us-gaap:DefinedBenefitPlanContributionsByEmployer

us-gaap:DefinedBenefitPlanContributionsByEmployer


Defined
Period End2021-06-302021-03-31
Value4.05.0
Percentage of DefinedBenefitPlanContributionsByEmployer100.0100.0

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
Value2000000.01000000.01000000.02000000.02000000.01000000.02000000.01000000.01000000.02000000.01000000.02000000.02000000.02000000.02000000.01000000.02000000.01000000.01000000.02000000.01000000.0
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
Value1000000.01000000.02000000.01000000.01000000.01000000.01000000.02000000.01000000.01000000.01000000.01000000.01000000.02000000.01000000.02000000.01000000.01000000.01000000.01000000.01000000.0
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:OtherPostretirementBenefitPlansDefinedBenefit


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
Value1.01.00.01.01.01.00.01.01.01.01.01.01.01.00.01.00.01.01.01.06.0
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost100.0100.00.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.00.0100.00.0100.0100.0100.0100.0

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value2.02.01.02.03.03.06.02.03.02.02.03.02.03.02.03.04.04.012
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost0.0200.0100.0200.00.0300.0600.0200.0300.0200.0200.0300.00.0300.00.0300.0400.0400.0200.0

us-gaap:DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1 us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2021-06-302020-06-302019-12-312019-09-302019-06-302018-12-312018-09-302018-06-302016-12-312016-09-302016-06-30
Value-1000000.00-1000000.0-1000000.0-4000000.0000-1000000.0-2000000.0-8000000.0
Percentage of DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1100.00.0100.0100.0100.00.00.00.0100.0100.0100.0

us-gaap:DefinedBenefitPlanServiceCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanServiceCost

us-gaap:PensionPlansDefinedBenefit


Defined
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value1.02.02.02.02.01.02.02.02.02.03.03.02.02.03.02.02.03.02.0
Percentage of DefinedBenefitPlanServiceCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeGainLossOnDerivativeNet

us-gaap:DerivativeGainLossOnDerivativeNet


Derivative
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-871.0-191.0186-192.0-109.033954100152-32.0-10.0-65.0-36.0-7.012448134116-311.071-85.0-14.017151.014
Percentage of DerivativeGainLossOnDerivativeNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount

us-gaap:EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount


Employee
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value5.05.02.01.00.01.02.04.02.01.03.02.04.04.02.02.03.06.06.05.04.04.04.542.8092.8722.862-3.322.4822.4422.864-2.6382.1881.9051.91-2.4171.6991.6891.708
Percentage of EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GainLossOnDerivativeInstrumentsNetPretax

us-gaap:GainLossOnDerivativeInstrumentsNetPretax


Gain
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-31
Value-871.0-191.0186-192.0-109.033954100152-32.0-10.0-65.0-36.0-7.012745134116-311.071-85.0-14.017151.01416878-8.0-99.72-49.6381293-29.794-4.357-5.879-6.3481.634
Percentage of GainLossOnDerivativeInstrumentsNetPretax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:GainLossOnDerivativeInstrumentsNetPretax us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Gain
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value-872.0-191.0-192.0-109.0339100152-32.0-65.0-36.0-7.012645134116-311.071-85.0-13.019152.01516979-7.0-100.0
Percentage of GainLossOnDerivativeInstrumentsNetPretax100.1100.0100.0100.0100.0100.0100.0100.0100.0100.0100.099.2100.0100.0100.0100.0100.0100.092.9111.8100.0200.0107.1100.6101.387.5100.3

us-gaap:CorporateAndOther


Gain
Period End2021-06-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312015-12-312015-09-302015-06-302015-03-31
Value1.00.00.00.00.00.00.00.00.0-2.00.0-1.0-1.0
Percentage of GainLossOnDerivativeInstrumentsNetPretax-0.1-0.00.00.00.0-0.0-0.0-0.0-0.0-11.80.0-100.0-7.1

us-gaap:IncreaseDecreaseInAccruedIncomeTaxesPayable

us-gaap:IncreaseDecreaseInAccruedIncomeTaxesPayable


Increase
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-4.0-8.05.0-1.0-5.0-6.03.03.0-10.04.02.04.08.0-12.07.0-8.013-8.012-14.09.0-12.015-13.0-10.0-20.0233.010-12.86319-32.30731-14.17726-24.551128.28511-8.8251.305-13.64525-5.1282.2072.006
Percentage of IncreaseDecreaseInAccruedIncomeTaxesPayable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInInterestPayableNet

us-gaap:IncreaseDecreaseInInterestPayableNet


Increase
Period End2021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-03-312015-12-312015-03-312014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-2.0-14.04.0-2.01.0-2.01.0-1.02.0-5.0-4.03.0-4.026-24.020-24.0-11.010.0-1.0-9.5127.305-7.2996.862-7.2457.364-7.06811-6.7179.975-9.2019.649-9.8139.987-9.98610-9.928
Percentage of IncreaseDecreaseInInterestPayableNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInOutstandingChecksFinancingActivities

us-gaap:IncreaseDecreaseInOutstandingChecksFinancingActivities


Increase
Period End2021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value7.010.0-1.0-13.05.0-8.0-4.0-10.03.07.010.00.00.0-3.06.0-1.02.0-2.0-19.0-14.0276.0-7.0-34.0151019-56.2827-11.83233-37.23532-10.21-20.52141.361-8.48917-17.0910.4871.0024.057
Percentage of IncreaseDecreaseInOutstandingChecksFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends us-gaap:AwardType

us-gaap:IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends

swn:RestrictedCommonStock


Incremental
Period End2021-03-31
Value870540.0
Percentage of IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends100.0

us-gaap:RestrictedStockUnitsRSU


Incremental
Period End2021-03-31
Value804940.0
Percentage of IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends92.5

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements us-gaap:AwardType

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:PerformanceShares


Incremental
Period End2021-03-31
Value2807200.0
Percentage of IncrementalCommonSharesAttributableToShareBasedPaymentArrangements100.0

us-gaap:InterestCostsCapitalizedAdjustment

us-gaap:InterestCostsCapitalizedAdjustment


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value212221232123252728292929292828292828294141414953544815141313141517
Percentage of InterestCostsCapitalizedAdjustment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:InterestExpenseOther

us-gaap:InterestExpenseOther


Interest
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value3.03.04.02.03.02.03.02.02.01.02.02.02.02.02.02.03.02.02.08.02.02.06.02.03.0499.02.0-0.0621.0621.1521.0491.0441.111.3581.0581.0470.9910.8920.9021.0011.5110.4880.5030.5050.439
Percentage of InterestExpenseOther100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeFinalizationOfPensionAndNonPensionPostretirementPlanValuationTax

us-gaap:OtherComprehensiveIncomeFinalizationOfPensionAndNonPensionPostretirementPlanValuationTax


Other
Period End2021-06-302020-06-30
Value-1000000.00
Percentage of OtherComprehensiveIncomeFinalizationOfPensionAndNonPensionPostretirementPlanValuationTax100.00.0

us-gaap:OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax

us-gaap:OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax


Other
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value1.00.00.01.04.00.06.04.00.00.00.01.01.0121.0-1.01.01.01.00.081-0.28-0.266-0.2670.267-0.246-0.254-0.254
Percentage of OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax100.00.00.0100.0100.00.0100.0100.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax

us-gaap:OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax


Other
Period End2020-09-302019-09-302019-06-302018-09-302018-06-302017-09-302017-06-302017-03-312016-03-312015-12-312014-12-312014-09-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value01000000.01000000.01000000.01000000.01000000.01000000.01000000.01000000.0-1000000.000100000.0200000.0200000.0200000.0200000.0200000.0200000.0100000.0
Percentage of OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax0.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationNetOfTax

us-gaap:OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationNetOfTax


Other
Period End2021-06-30
Value3000000.0
Percentage of OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationNetOfTax100.0

us-gaap:OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome


Other
Period End2021-06-30
Value3000000.0
Percentage of OtherComprehensiveIncomeLossFinalizationOfPensionAndNonPensionPostretirementPlanValuationNetOfTax100.0

us-gaap:OtherCostAndExpenseOperating

us-gaap:OtherCostAndExpenseOperating


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value25925023620218219319718916916519720619318919017016414713713915116518217617615511810810110091908264656156606563555651525036
Percentage of OtherCostAndExpenseOperating100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherOperatingActivitiesCashFlowStatement

us-gaap:OtherOperatingActivitiesCashFlowStatement


Other
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312014-12-312014-03-312013-12-312013-03-31
Value3.03.00.00.0-1.01.09.01.0-8.06.0-2.03.0152.0-2.0-2.03.0-2.02.05.0325.00.508-2.0-0.476
Percentage of OtherOperatingActivitiesCashFlowStatement100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForProceedsFromOtherInvestingActivities

us-gaap:PaymentsForProceedsFromOtherInvestingActivities


Payments
Period End2021-06-302021-03-312019-12-312019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.01.00.00.0-2.0-1.0-1.0-2.0-1.0-4.03.0-4.0-3.03.0-7.0-3.0-4.0-3.0-1.691-1.309-5.4660.928-4.59-1.038-3.283.656-7.125-1.77-0.218-1.061-4.2540.3750.0520.1873.094-0.649
Percentage of PaymentsForProceedsFromOtherInvestingActivities0.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForRestructuring us-gaap:RestructuringCostAndReserve

us-gaap:PaymentsForRestructuring

us-gaap:OtherRestructuring


Payments
Period End2021-06-302021-03-31
Value1.09.0
Percentage of PaymentsForRestructuring100.0100.0

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation

us-gaap:PaymentsRelatedToTaxWithholdingForShareBasedCompensation


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
Value03000000.03000000.001000000.000001000000.02000000.0001000000.0
Percentage of PaymentsRelatedToTaxWithholdingForShareBasedCompensation0.0100.0100.00.0100.00.00.00.00.0100.0100.00.00.0100.0

us-gaap:ProceedsFromLongTermLinesOfCredit

us-gaap:ProceedsFromLongTermLinesOfCredit


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value8607909221946066155660.00.00.05014770.00.0552260069234447413301767105413661008105291410584044635262.4599942913947892718858836641
Percentage of ProceedsFromLongTermLinesOfCredit100.0100.0100.0100.0100.0100.0100.00.00.00.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProceedsFromSaleOfPropertyPlantAndEquipment

us-gaap:ProceedsFromSaleOfPropertyPlantAndEquipment


Proceeds
Period End2021-06-302021-03-312020-12-312020-09-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1.01.010.00.01216260.016343.00.06.0-7.05.010.02.0-4.0380251.07021.0233.00.01715-0.06261730.651320.413110111.8480.0053480.0
Percentage of ProceedsFromSaleOfPropertyPlantAndEquipment100.0100.0100.00.0100.0100.0100.00.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax us-gaap:StatementEquityComponents

us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax

us-gaap:AccumulatedDefinedBenefitPlansAdjustment


Reclassification
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-12-312017-12-312017-09-302016-12-312016-03-312015-12-312014-03-312013-12-312013-09-30
Value-1.00.00.0-1.0-4.00.0-6.00.0-1.0-12.0-1.02.00.081110.266
Percentage of ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax100.00.00.0100.0100.00.0100.00.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccumulatedOtherComprehensiveIncome


Reclassification
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value-1.00.00.0-1.0-4.00.0
Percentage of ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax100.00.00.0100.0100.00.0

us-gaap:RepaymentsOfLongTermLinesOfCredit

us-gaap:RepaymentsOfLongTermLinesOfCredit


Repayments
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value8599232225304195005320.00.00.08614770.00.02404864856634704830160610871354113110139018633694895002.41271870857934782914746675621
Percentage of RepaymentsOfLongTermLinesOfCredit100.0100.0100.0100.0100.0100.0100.00.00.00.0100.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:RepaymentsOfOtherLongTermDebt

us-gaap:RepaymentsOfOtherLongTermDebt


Repayments
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-31
Value0.00.0205211430.00.0
Percentage of RepaymentsOfOtherLongTermDebt0.00.0100.0100.0100.0100.00.00.0

us-gaap:RestructuringCharges

us-gaap:RestructuringCharges


Restructuring
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312016-12-312016-09-302016-06-302016-03-31
Value1.06.04.00.02.010.02.04.02.03.0192.0180.01.02.01164
Percentage of RestructuringCharges100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0

us-gaap:RestructuringCharges us-gaap:RestructuringCostAndReserve

us-gaap:OtherRestructuring


Restructuring
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302016-12-312016-09-302016-06-302016-03-31
Value1.06.04.00.02.010.0-9.04.02.03.03.02.018-4.02.01164
Percentage of RestructuringCharges100.0100.0100.00.0100.0100.0-450.0100.0100.0100.015.8100.0100.0-400.0100.0100.0100.0

us-gaap:RestructuringCharges us-gaap:RestructuringCostAndReserve, us-gaap:StatementBusinessSegments

us-gaap:OtherRestructuring, swn:ExplorationAndProduction


Restructuring
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302016-12-312016-09-302016-06-302016-03-31
Value1.06.00.02.010.04.02.03.02.0161.02.01161
Percentage of RestructuringCharges100.0100.00.0100.0100.0100.0100.0100.0100.088.9100.0100.0100.095.3

us-gaap:RestructuringCharges us-gaap:StatementBusinessSegments

swn:ExplorationAndProduction


Restructuring
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302016-09-302016-06-302016-03-31
Value1.06.00.02.010.04.02.03.02.0162.01161
Percentage of RestructuringCharges100.0100.00.0100.0100.0100.0100.0100.0100.088.9100.0100.095.3

us-gaap:SaleOfStockConsiderationReceivedOnTransaction us-gaap:BusinessAcquisition, us-gaap:SubsidiarySaleOfStock

us-gaap:SaleOfStockConsiderationReceivedOnTransaction

swn:MontageResourcesCorporation, swn:PublicStockOffering


Sale
Period End2020-08-31
Value152
Percentage of SaleOfStockConsiderationReceivedOnTransaction100.0

us-gaap:SeveranceCosts1 us-gaap:RestructuringCostAndReserve

us-gaap:SeveranceCosts1

us-gaap:OtherRestructuring


Severance
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302016-09-302016-06-302016-03-31
Value1.06.00.02.010.01.01.02.01.0170.02.042
Percentage of SeveranceCosts1100.0100.00.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod

us-gaap:RestrictedStock


Share
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302014-12-312014-09-302014-06-302014-03-31
Value23000.05000.074000.0167000.04000.035000.030000.0145000.0686000.0236000.0747000.0160000.0133000.0193000.0303000.0113000.027000.049000.065000.024000.033000.016000.025000.050000.024764.042236.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue

us-gaap:RestrictedStock


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302015-12-312015-09-302014-12-312014-09-302014-06-302014-03-31
Value08.590.080.02-0.98.5900.01-0.018.38-0.020-4.4-0.01-0.030-0.1838.12
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue0.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.00.0100.0100.0100.00.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue

us-gaap:RestrictedStock


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-31
Value2.322.98-0.0200.462.42-0.03-1.030.43.720.010.04-17.98-0.18-0.0426.27-14.92-0.243.0443.01
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod

us-gaap:PerformanceShares


Share
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302017-12-312017-09-302016-12-312016-09-302016-06-302016-03-31
Value000178000.07000.000371000.000283000.040000.0475000.02000.0407000.05000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod0.00.00.0100.0100.00.00.0100.00.00.0100.0100.0100.0100.0100.0100.0

us-gaap:RestrictedStock


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302014-12-312014-09-302014-06-302014-03-31
Value404000.0451000.015000.080000.0481000.0522000.0415000.0111000.0382000.0608000.0596000.0-10000.0439000.01033000.01133000.0100000.077000.070000.01292000.063000.0515000.01947000.0775000.081000.0526000.07000.010853.04147.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod0.00.00.00.00.0293.35928.60.00.0163.90.00.00.00.0400.4250.00.00.0272.03150.0126.538940.00.00.00.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-31
Value42000.045000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod0.00.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue

us-gaap:PerformanceShares


Share
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value00010.47-0.14009.7300
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue0.00.00.0100.0100.00.00.0100.00.00.0

us-gaap:RestrictedStock


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302015-12-312015-09-302014-12-312014-09-302014-06-302014-03-31
Value-1.787.61-0.04-0.19-2.267.750.14-0.35-1.378.740.850.03-1.63-3.060.50.14-0.2136.69
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue0.00.00.00.00.074.0-100.00.00.089.80.00.00.00.00.00.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-31
Value03.05
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue0.00.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod

us-gaap:EmployeeStockOption


Share
Period End2021-06-302021-03-31
Value90000.061000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod100.0100.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice

us-gaap:EmployeeStockOption


Share
Period End2021-06-302021-03-31
Value21.2810.93
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice100.0100.0

us-gaap:StockIssuedDuringPeriodValueAcquisitions us-gaap:BusinessAcquisition, us-gaap:StatementEquityComponents

us-gaap:StockIssuedDuringPeriodValueAcquisitions

swn:MontageResourcesCorporation, us-gaap:AdditionalPaidInCapital


Stock
Period End2020-11-13
Value212
Percentage of StockIssuedDuringPeriodValueAcquisitions100.0

swn:MontageResourcesCorporation, us-gaap:CommonStock


Stock
Period End2020-11-13
Value1.0
Percentage of StockIssuedDuringPeriodValueAcquisitions0.5

us-gaap:StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures

us-gaap:StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures


Stock
Period End2021-03-312020-06-302020-03-31
Value8000000.02000000.01000000.0
Percentage of StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures100.0100.0100.0

us-gaap:StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital


Stock
Period End2021-03-312020-06-302020-03-31
Value8000000.02000000.01000000.0
Percentage of StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures100.0100.0100.0

us-gaap:StockIssuedDuringPeriodValueShareBasedCompensationGross

us-gaap:StockIssuedDuringPeriodValueShareBasedCompensationGross


Stock
Period End2021-03-31
Value4000000.0
Percentage of StockIssuedDuringPeriodValueShareBasedCompensationGross100.0

us-gaap:StockIssuedDuringPeriodValueShareBasedCompensationGross us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital


Stock
Period End2021-03-31
Value4000000.0
Percentage of StockIssuedDuringPeriodValueShareBasedCompensationGross100.0

us-gaap:TaxesExcludingIncomeAndExciseTaxes

us-gaap:TaxesExcludingIncomeAndExciseTaxes


Taxes
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value2724171510.01311151719252615231924252624242223262727302322242520172020161614201617151611141013
Percentage of TaxesExcludingIncomeAndExciseTaxes100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:UnrealizedGainLossOnDerivatives

us-gaap:UnrealizedGainLossOnDerivatives


Unrealized
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-772.0-169.0134-289.0-229.0246-14.012118-22.089-59.0-56.02.010131173146-325.081-108.0-21.0-50.0-34.0-50.0-21.013755-0.1-61.9-51.2841093-30.8-2.618-1.67711-7.324-1.1864.88-2.895-1.08-0.785-1.2292.212-4.487
Percentage of UnrealizedGainLossOnDerivatives100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows


Future
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value179972700334523365769064
Percentage of FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows100.0100.0100.0100.0100.0

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts


Future
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value1924324640954676485
Percentage of FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts100.0100.0100.0100.0100.0

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows


Future
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value4104830013002121682699
Percentage of FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows100.0100.0100.0100.0100.0

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts


Future
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value119691498115347183905880
Percentage of FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts100.0100.0100.0100.0100.0

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows

srt:FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows


Future
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value22574600700366061034
Percentage of FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows100.0100.0100.0100.0100.0

srt:ProvedDevelopedAndUndevelopedReserveNetEnergy

srt:ProvedDevelopedAndUndevelopedReserveNetEnergy


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value119901272111921147755253
Percentage of ProvedDevelopedAndUndevelopedReserveNetEnergy100.0100.0100.0100.0100.0

srt:ProvedDevelopedAndUndevelopedReserveNetEnergy us-gaap:StatementGeographical

country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value119901272111921147755253
Percentage of ProvedDevelopedAndUndevelopedReserveNetEnergy100.0100.0100.0100.0100.0

srt:OtherProperty


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value1.01.01.08.05.0
Percentage of ProvedDevelopedAndUndevelopedReserveNetEnergy0.00.00.00.10.1

swn:NortheastAppalachia


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value49164837436641261574
Percentage of ProvedDevelopedAndUndevelopedReserveNetEnergy41.038.036.627.930.0

swn:SouthwestAppalachia


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value7073788375546962677
Percentage of ProvedDevelopedAndUndevelopedReserveNetEnergy59.062.063.447.112.9

srt:ProvedDevelopedAndUndevelopedReservesNet us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:StatementGeographical

srt:ProvedDevelopedAndUndevelopedReservesNet

srt:NaturalGasLiquidsReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value4106080.5770630.5424550.0539310.040947
Percentage of ProvedDevelopedAndUndevelopedReservesNet100.0100.0100.0100.0100.0100.0

srt:NaturalGasReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value9181863080440001112600048660005917000
Percentage of ProvedDevelopedAndUndevelopedReservesNet2238.41417.61393955252.72051045708.99022640040.114450387085.7

srt:OilReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value58720.0690070.0656360.0105230.008753
Percentage of ProvedDevelopedAndUndevelopedReservesNet14.112.012.012.119.521.4

srt:ProvedDevelopedReservesBOE1 us-gaap:StatementGeographical

srt:ProvedDevelopedReservesBOE1

country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-31
Value8203642155577920
Percentage of ProvedDevelopedReservesBOE1100.0100.0100.0100.0

srt:ProvedDevelopedReservesVolume us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:StatementGeographical

srt:ProvedDevelopedReservesVolume

srt:NaturalGasLiquidsReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value2762260.175480.1422130.053931
Percentage of ProvedDevelopedReservesVolume100.0100.0100.0100.0100.0

srt:NaturalGasReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value63424906439500069790004789000
Percentage of ProvedDevelopedReservesVolume2293.32168.22504558924.14907427591.08879865012.7

srt:OilReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value33260.0180370.0145130.010523
Percentage of ProvedDevelopedReservesVolume12.111.510.310.219.5

srt:ProvedUndevelopedReserveBOE1

srt:ProvedUndevelopedReserveBOE1


Proved
Period End2020-12-312019-12-312018-12-312017-12-31
Value24379291901375
Percentage of ProvedUndevelopedReserveBOE1100.0100.0100.0100.0

srt:ProvedUndevelopedReserveBOE1 us-gaap:StatementGeographical

country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-31
Value3787630063646855
Percentage of ProvedUndevelopedReserveBOE1155.4678.13349.5498.5

srt:ProvedUndevelopedReserveVolume us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:StatementGeographical

srt:ProvedUndevelopedReserveVolume

srt:NaturalGasLiquidsReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-31
Value1333820.4015830.400242
Percentage of ProvedUndevelopedReserveVolume100.0100.0100.0100.0

srt:NaturalGasReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-312016-12-31
Value283937243649000414700077000
Percentage of ProvedUndevelopedReserveVolume2125.0973.6908654001.81036123145.50.0

srt:OilReserves, country:US


Proved
Period End2020-12-312019-12-312018-12-312017-12-31
Value24460.050970.051123
Percentage of ProvedUndevelopedReserveVolume18.312.212.712.8

srt:StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves

srt:StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves


Standardized
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value184737005999556216652417
Percentage of StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves100.0100.0100.0100.0100.0100.0

swn:AggregateAnnualLeasePayment us-gaap:PropertyPlantAndEquipmentByType, us-gaap:StatementBusinessSegments

swn:AggregateAnnualLeasePayment

swn:DrillingRigs, swn:ExplorationAndProductionReportableSegment


Aggregate
Period End2020-12-312019-12-312018-12-31
Value111313
Percentage of AggregateAnnualLeasePayment100.0100.0100.0

swn:PressurePumpingEquipment, swn:ExplorationAndProductionReportableSegment


Aggregate
Period End2020-12-312019-12-312018-12-31
Value6.06.07.0
Percentage of AggregateAnnualLeasePayment54.546.253.8

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDerivativeAssets us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDerivativeAssets

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value11
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDerivativeAssets100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEvaluatedOilAndGasProperties us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEvaluatedOilAndGasProperties

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value1012
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedEvaluatedOilAndGasProperties100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesAssetRetirementObligation us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesAssetRetirementObligation

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value28
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesAssetRetirementObligation100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesRevolvingCreditFacility us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesRevolvingCreditFacility

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value200
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesRevolvingCreditFacility100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesSeniorNotes us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesSeniorNotes

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value522
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesSeniorNotes100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipmentOther us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipmentOther

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value28
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipmentOther100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProvedOilAndGasProperty us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProvedOilAndGasProperty

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value1000
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedProvedOilAndGasProperty100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnevaluatedOilAndGasProperties us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnevaluatedOilAndGasProperties

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value90
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnevaluatedOilAndGasProperties100.0

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnprovedOilAndGasProperty us-gaap:BusinessAcquisition

swn:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnprovedOilAndGasProperty

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value90
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnprovedOilAndGasProperty100.0

swn:CapitalizedInterestOfNetUnevaluatedCostsExcludedFromAmortizationCumulative

swn:CapitalizedInterestOfNetUnevaluatedCostsExcludedFromAmortizationCumulative


Capitalized
Period End2020-12-312019-12-31
Value188179
Percentage of CapitalizedInterestOfNetUnevaluatedCostsExcludedFromAmortizationCumulative100.0100.0

swn:CapitalizedInterestOfNetUnevaluatedCostsExcludedFromAmortizationCumulative us-gaap:StatementGeographical

swn:WellsInProgress


Capitalized
Period End2020-12-312019-12-31
Value188179
Percentage of CapitalizedInterestOfNetUnevaluatedCostsExcludedFromAmortizationCumulative100.0100.0

swn:DeferredTaxAssetsFutureOperatingLeasePayments

swn:DeferredTaxAssetsFutureOperatingLeasePayments


Deferred
Period End2020-12-312019-12-312018-12-31
Value38370.0
Percentage of DeferredTaxAssetsFutureOperatingLeasePayments100.0100.00.0

swn:DerivativeBasisDifferentialPerMillionBritishThermalUnit us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

swn:DerivativeBasisDifferentialPerMillionBritishThermalUnit

swn:BasisSwapsStorage2021, us-gaap:Nondesignated


Derivative
Period End2020-12-31
Value-0.38
Percentage of DerivativeBasisDifferentialPerMillionBritishThermalUnit100.0

swn:DerivativeBasisDifferentialPerMillionBritishThermalUnit us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

srt:NaturalGasReserves, swn:BasisSwapFive, us-gaap:Nondesignated


Derivative
Period End2020-12-31
Value-0.59
Percentage of DerivativeBasisDifferentialPerMillionBritishThermalUnit155.3

srt:NaturalGasReserves, swn:BasisSwapFour, us-gaap:Nondesignated


Derivative
Period End2020-12-31
Value-0.6
Percentage of DerivativeBasisDifferentialPerMillionBritishThermalUnit157.9

srt:NaturalGasReserves, swn:BasisSwapOne, us-gaap:Nondesignated


Derivative
Period End2020-12-31
Value-0.21
Percentage of DerivativeBasisDifferentialPerMillionBritishThermalUnit55.3

srt:NaturalGasReserves, swn:BasisSwapThree, us-gaap:Nondesignated


Derivative
Period End2020-12-31
Value-0.45
Percentage of DerivativeBasisDifferentialPerMillionBritishThermalUnit118.4

srt:NaturalGasReserves, swn:BasisSwapTwo, us-gaap:Nondesignated


Derivative
Period End2020-12-31
Value-0.33
Percentage of DerivativeBasisDifferentialPerMillionBritishThermalUnit86.8

swn:DerivativeBasisDifferentialperMillionBritishThermalUnit us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

swn:DerivativeBasisDifferentialperMillionBritishThermalUnit

swn:BasisSwapsStorage2021, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-31
Value-0.32-0.57
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit100.0100.0

swn:BasisSwapsStorage2022, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-31
Value0-0.57
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit-0.0100.0

swn:PurchasedBasisSwapsStorage2020, us-gaap:Nondesignated


Derivative
Period End2020-09-302020-06-302020-03-31
Value-0.05-0.09-0.49
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit0.00.00.0

swn:PurchasedBasisSwapsStorage2021, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-31
Value0-0.88
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit-0.0154.4

swn:DerivativeBasisDifferentialperMillionBritishThermalUnit us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

srt:NaturalGasReserves, swn:BasisSwap2020, us-gaap:Nondesignated


Derivative
Period End2020-09-302020-06-302020-03-312019-09-302019-06-302019-03-31
Value0.070-0.440.030.1-0.44
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit0.00.00.00.00.00.0

srt:NaturalGasReserves, swn:BasisSwap2021, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-30
Value0.02-0.490.02-0.11-0.030.03
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit-6.386.00.00.00.00.0

srt:NaturalGasReserves, swn:BasisSwap2022, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-312020-09-302020-06-302020-03-31
Value0.04-0.440.080.02-0.48
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit-12.577.20.00.00.0

srt:NaturalGasReserves, swn:BasisSwap2023, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-31
Value0.03-0.56
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit-9.498.2

srt:NaturalGasReserves, swn:BasisSwap2024, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-31
Value-0.06-0.64
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit18.7112.3

srt:NaturalGasReserves, swn:BasisSwap2025, us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-31
Value0-0.64
Percentage of DerivativeBasisDifferentialperMillionBritishThermalUnit-0.0112.3

swn:DerivativeLiabilityIncreaseDecreaseImpactNonPerformingRisk us-gaap:HedgingDesignation

swn:DerivativeLiabilityIncreaseDecreaseImpactNonPerformingRisk

us-gaap:Nondesignated


Derivative
Period End2021-06-302021-03-312020-12-312020-09-30
Value-2000000.0-1000000.0-1000000.0-1000000.0
Percentage of DerivativeLiabilityIncreaseDecreaseImpactNonPerformingRisk100.0100.0100.0100.0

swn:DerivativeLiabilityIncreaseDecreaseImpactNonPerformingRisk us-gaap:ReserveQuantitiesByTypeOfReserve, us-gaap:DerivativeInstrumentRisk, us-gaap:FinancialInstrumentPerformanceStatus

srt:NaturalGasReserves, swn:FixedPriceSwaps, us-gaap:NonperformingFinancingReceivable


Derivative
Period End2020-09-30
Value-1000000.0
Percentage of DerivativeLiabilityIncreaseDecreaseImpactNonPerformingRisk100.0

swn:ExplorationAndDevelopmentCostsCumulative

swn:ExplorationAndDevelopmentCostsCumulative


Exploration
Period End2020-12-31
Value68
Percentage of ExplorationAndDevelopmentCostsCumulative100.0

swn:IncomeTaxAlternativeMinimumTaxRefundSequesteredAmount

swn:IncomeTaxAlternativeMinimumTaxRefundSequesteredAmount


Income
Period End2020-12-31
Value2000000.0
Percentage of IncomeTaxAlternativeMinimumTaxRefundSequesteredAmount100.0

swn:LesseeOperatingLeaseNotYetCommenced

swn:LesseeOperatingLeaseNotYetCommenced


Lessee
Period End2020-12-31
Value6000000.0
Percentage of LesseeOperatingLeaseNotYetCommenced100.0

swn:LiabilityBasedPerformanceUnitsShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized us-gaap:AwardType

swn:LiabilityBasedPerformanceUnitsShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized

swn:LiabilityClassifiedPerformanceUnits


Liability
Period End2020-12-31
Value14
Percentage of LiabilityBasedPerformanceUnitsShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized100.0

swn:LiabilityBasedRestrictedStockShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized us-gaap:AwardType

swn:LiabilityBasedRestrictedStockShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized

swn:LiabilityClassifiedRestrictedStockUnits


Liability
Period End2020-12-31
Value22
Percentage of LiabilityBasedRestrictedStockShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized100.0

swn:RestrictedCashUnits


Liability
Period End2020-12-31
Value14
Percentage of LiabilityBasedRestrictedStockShareBasedCompensationNonvestedAwardsCompensationCostNotYetRecognized63.6

swn:LongTermDebtCurrentMaturitiesGross us-gaap:LongtermDebtType

swn:LongTermDebtCurrentMaturitiesGross

us-gaap:SeniorNotes


Long
Period End2021-06-302021-03-312019-09-302019-06-302019-03-31
Value207207525252
Percentage of LongTermDebtCurrentMaturitiesGross100.0100.0100.0100.0100.0

swn:NetBookValueAdjustedForMarketDifferentials

swn:NetBookValueAdjustedForMarketDifferentials


Net
Period End2020-12-312020-09-302020-06-302020-03-31
Value3353616501480
Percentage of NetBookValueAdjustedForMarketDifferentials100.0100.0100.0100.0

swn:OperatingLossCarryforwardsLimitationOfUse

swn:OperatingLossCarryforwardsLimitationOfUse


Operating
Period End2020-12-31
Value90
Percentage of OperatingLossCarryforwardsLimitationOfUse100.0

swn:OperatingLossCarryforwardsLimitationOfUse us-gaap:BusinessAcquisition

swn:MontageResourcesCorporation


Operating
Period End2020-12-31
Value1.7
Percentage of OperatingLossCarryforwardsLimitationOfUse1.9

swn:OtherCommitmentAssumedByBuyer

swn:OtherCommitmentAssumedByBuyer


Other
Period End2020-09-302019-12-312019-09-302019-06-302019-03-312018-12-312018-09-30
Value27108135162188564564
Percentage of OtherCommitmentAssumedByBuyer100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentDueAfterEighthYear

swn:OtherCommitmentDueAfterEighthYear


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value29062825289626432700278135593332344937433601388039553855390938353613370835363718
Percentage of OtherCommitmentDueAfterEighthYear100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentDueAfterEighthYear us-gaap:BusinessAcquisition, us-gaap:OtherCommitments

swn:MontageResourcesCorporation, swn:FirmTransportationCommitments


Other
Period End2020-12-31
Value324
Percentage of OtherCommitmentDueAfterEighthYear11.2

swn:OtherCommitmentDueAfterEighthYear us-gaap:OtherCommitments

swn:InfrastructureCurrentlyInService


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value26342540252223252404248528502886288729012019203519932094228518191627165716431756
Percentage of OtherCommitmentDueAfterEighthYear90.689.987.188.089.089.480.186.683.777.556.152.450.454.358.547.445.044.746.547.2

swn:PendingRegulatoryApprovalAndOrConstruction


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value2722853743182962967094465628421582184519621761162420161986205118931962
Percentage of OtherCommitmentDueAfterEighthYear9.410.112.912.011.010.619.913.416.322.543.947.649.645.741.552.655.055.353.552.8

swn:OtherCommitmentDueInFifthAndEighthYear

swn:OtherCommitmentDueInFifthAndEighthYear


Other
Period End2020-12-312019-12-312019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value1901173918051744183118371777174216061557156215071545
Percentage of OtherCommitmentDueInFifthAndEighthYear100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentDueInFifthAndEighthYear us-gaap:BusinessAcquisition, us-gaap:OtherCommitments

swn:MontageResourcesCorporation, swn:FirmTransportationCommitments


Other
Period End2020-12-31
Value284
Percentage of OtherCommitmentDueInFifthAndEighthYear14.9

swn:OtherCommitmentDueInFifthAndEighthYear us-gaap:OtherCommitments

swn:InfrastructureCurrentlyInService


Other
Period End2020-12-312019-12-312019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value181315311520112311361106115111551492843832829851
Percentage of OtherCommitmentDueInFifthAndEighthYear95.488.084.264.462.060.264.866.392.954.153.355.055.1

swn:PendingRegulatoryApprovalAndOrConstruction


Other
Period End2020-12-312019-12-312019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-30
Value88208285621695731626587114714730678694
Percentage of OtherCommitmentDueInFifthAndEighthYear4.612.015.835.638.039.835.233.77.145.946.745.044.9

swn:OtherCommitmentDueInFirstThroughThirdYear

swn:OtherCommitmentDueInFirstThroughThirdYear


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value157515691562131713401356123513451382141714081460151115251565156315261510148414341367
Percentage of OtherCommitmentDueInFirstThroughThirdYear100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentDueInFirstThroughThirdYear us-gaap:BusinessAcquisition, us-gaap:OtherCommitments

swn:MontageResourcesCorporation, swn:FirmTransportationCommitments


Other
Period End2020-12-31
Value197
Percentage of OtherCommitmentDueInFirstThroughThirdYear12.6

swn:OtherCommitmentDueInFirstThroughThirdYear us-gaap:OtherCommitments

swn:InfrastructureCurrentlyInService


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value155715391532130813231339120012721304130410601100116712081240110511281139115811401136
Percentage of OtherCommitmentDueInFirstThroughThirdYear98.998.198.199.398.798.797.294.694.492.075.375.377.279.279.270.773.975.478.079.583.1

swn:PendingRegulatoryApprovalAndOrConstruction


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value1830309.01717357378113348360344317325458398371326294231
Percentage of OtherCommitmentDueInFirstThroughThirdYear1.11.91.90.71.31.32.85.45.68.024.724.722.820.820.829.326.124.622.020.516.9

swn:OtherCommitmentDueInLessThanTwelveMonths

swn:OtherCommitmentDueInLessThanTwelveMonths


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value715791862585669754768700711727773733710685702628626627627559574
Percentage of OtherCommitmentDueInLessThanTwelveMonths100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentDueInLessThanTwelveMonths us-gaap:BusinessAcquisition, us-gaap:OtherCommitments

swn:MontageResourcesCorporation, swn:FirmTransportationCommitments


Other
Period End2020-12-31
Value99
Percentage of OtherCommitmentDueInLessThanTwelveMonths11.5

swn:OtherCommitmentDueInLessThanTwelveMonths us-gaap:OtherCommitments

swn:InfrastructureCurrentlyInService


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value713789860582667753767681702723637607632639671196580592612545561
Percentage of OtherCommitmentDueInLessThanTwelveMonths99.799.799.899.599.799.999.997.398.799.482.482.889.093.395.631.292.794.497.697.597.7

swn:PendingRegulatoryApprovalAndOrConstruction


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value2.02.02.03.02.01.01.0199.04.01361267846314324635151413
Percentage of OtherCommitmentDueInLessThanTwelveMonths0.30.30.20.50.30.10.12.71.30.617.617.211.06.74.468.87.35.62.42.52.3

swn:OtherCommitmentDueInThirdThroughFifthYear

swn:OtherCommitmentDueInThirdThroughFifthYear


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value134213331323110111131121116911501218130212681294131512831253122612301265127513301335
Percentage of OtherCommitmentDueInThirdThroughFifthYear100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentDueInThirdThroughFifthYear us-gaap:BusinessAcquisition, us-gaap:OtherCommitments

swn:MontageResourcesCorporation, swn:FirmTransportationCommitments


Other
Period End2020-12-31
Value196
Percentage of OtherCommitmentDueInThirdThroughFifthYear14.8

swn:OtherCommitmentDueInThirdThroughFifthYear us-gaap:OtherCommitments

swn:InfrastructureCurrentlyInService


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value1317129512861078109110981066107510971135876865864894884524766791825865883
Percentage of OtherCommitmentDueInThirdThroughFifthYear98.197.197.297.998.097.991.293.590.187.269.166.865.769.770.642.762.362.564.765.066.1

swn:PendingRegulatoryApprovalAndOrConstruction


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-30
Value25383723222310375121167392429451389369702464474450465452
Percentage of OtherCommitmentDueInThirdThroughFifthYear1.92.92.82.12.02.18.86.59.912.830.933.234.330.329.457.337.737.535.335.033.9

swn:OtherCommitmentDueinFifthThroughEighthYear

swn:OtherCommitmentDueinFifthThroughEighthYear


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value1796183314631527159816671707
Percentage of OtherCommitmentDueinFifthThroughEighthYear100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentDueinFifthThroughEighthYear us-gaap:OtherCommitments

swn:InfrastructureCurrentlyInService


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value1744175214111462152415281511
Percentage of OtherCommitmentDueinFifthThroughEighthYear97.195.696.495.795.491.788.5

swn:PendingRegulatoryApprovalAndOrConstruction


Other
Period End2021-06-302021-03-312020-09-302020-06-302020-03-312019-09-302019-06-30
Value5281526574139196
Percentage of OtherCommitmentDueinFifthThroughEighthYear2.94.43.64.34.68.311.5

swn:OtherCommitmentLiabilityForEstimatedFuturePayments

swn:OtherCommitmentLiabilityForEstimatedFuturePayments


Other
Period End2020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value10.021364657687888
Percentage of OtherCommitmentLiabilityForEstimatedFuturePayments100.0100.0100.0100.0100.0100.0100.0100.0

swn:OtherCommitmentPotentialAmountToBeReimbursedToBuyer

swn:OtherCommitmentPotentialAmountToBeReimbursedToBuyer


Other
Period End2020-09-302019-09-302019-06-302019-03-31
Value13708294
Percentage of OtherCommitmentPotentialAmountToBeReimbursedToBuyer100.0100.0100.0100.0

swn:OtherLiabilitiesMiscellaneousCurrent

swn:OtherLiabilitiesMiscellaneousCurrent


Other
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value23232030374354921039548
Percentage of OtherLiabilitiesMiscellaneousCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:OutstandingChecksIncludedInAccountsPayable

swn:OutstandingChecksIncludedInAccountsPayable


Outstanding
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
Value161534178.029174.912472334
Percentage of OutstandingChecksIncludedInAccountsPayable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:Prepayments us-gaap:StatementBusinessSegments

swn:Prepayments

us-gaap:CorporateAndOther


Prepaymentsus-gaap:
Period End2020-09-302020-03-312019-09-302019-03-312018-09-30
Value3.09.07.010.012
Percentage of Prepayments100.0100.0100.0100.0100.0

swn:PresentValueOfProvedReservesDiscountedBasis

swn:PresentValueOfProvedReservesDiscountedBasis


Present
Period End2020-12-312019-12-312018-12-312017-12-31
Value2075024124
Percentage of PresentValueOfProvedReservesDiscountedBasis100.0100.0100.0100.0

swn:ReceivablesFromContractsWithCustomers

swn:ReceivablesFromContractsWithCustomers


Receivables
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value391381350218183195284235238297494330305273322
Percentage of ReceivablesFromContractsWithCustomers100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber

swn:LiabilityClassifiedPerformanceUnits


Share
Period End2020-12-312019-12-312018-12-312017-12-31
Value8.6995.1422.8030.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber100.0100.0100.00.0

swn:LiabilityClassifiedRestrictedStockUnits


Share
Period End2020-12-312019-12-312018-12-312017-12-31
Value11128.2020.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber133.5252.7292.60.0

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value2930181919190.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber0.00.0211.00.00.00.00.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value9.6379.6378.6999.0149.19115.1425.4415.4415.4412.8032.993.044
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber0.00.0100.00.00.00.0100.00.00.00.0100.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value8.0888.16111121213121313148.2029.68710
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedNumber0.00.0133.50.00.00.0252.70.00.00.0292.60.00.0

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue us-gaap:AwardType

swn:ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue

swn:LiabilityClassifiedPerformanceUnits


Share
Period End2020-12-312019-12-312018-12-312017-12-31
Value2.572.423.410
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue100.0100.0100.00.0

swn:LiabilityClassifiedRestrictedStockUnits


Share
Period End2020-12-312019-12-312018-12-312017-12-31
Value2.672.423.410
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue103.9100.0100.00.0

swn:RestrictedCashUnits


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-31
Value1.01.01.01.01.01.00
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue0.00.038.90.00.00.00.0

us-gaap:PerformanceShares


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value3.382.882.572.12.561.692.421.933.164.693.415.115.3
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue0.00.0100.00.00.00.0100.00.00.00.0100.00.00.0

us-gaap:RestrictedStockUnitsRSU


Share
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-30
Value4.94.072.672.172.561.692.421.933.164.693.415.115.3
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardLiabilityInstrumentsOtherThanOptionsNonvestedWeightedAverageFairValue0.00.0103.90.00.00.0100.00.00.00.0100.00.00.0

swn:TaxCreditCarryforwardsAlternativeMinimumTaxExpectedRefunds

swn:TaxCreditCarryforwardsAlternativeMinimumTaxExpectedRefunds


Tax
Period End2020-12-31
Value30
Percentage of TaxCreditCarryforwardsAlternativeMinimumTaxExpectedRefunds100.0

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax


Accumulated
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-31
Value282220-26.0-19.0-25.0
Percentage of AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax100.0100.0100.0100.0100.0100.0

us-gaap:AcquisitionCostsCumulative

us-gaap:AcquisitionCostsCumulative


Acquisition
Period End2020-12-31
Value1216
Percentage of AcquisitionCostsCumulative100.0

us-gaap:AssetRetirementObligation

us-gaap:AssetRetirementObligation


Asset
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-31
Value85576116514120120713310037272212
Percentage of AssetRetirementObligation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetRetirementObligationCurrent

us-gaap:AssetRetirementObligationCurrent


Asset
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
Value4.06.06.0126.010.09.05.5494.0911.5391.8290.854
Percentage of AssetRetirementObligationCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetRetirementObligationsNoncurrent

us-gaap:AssetRetirementObligationsNoncurrent


Asset
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
Value81515515313519119812796362522
Percentage of AssetRetirementObligationsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned us-gaap:BusinessAcquisition

us-gaap:BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value213
Percentage of BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned100.0

us-gaap:BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned us-gaap:BusinessAcquisition, us-gaap:StatementEquityComponents

swn:MontageResourcesCorporation, us-gaap:CommonStock


Business
Period End2020-11-13
Value213
Percentage of BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned100.0

us-gaap:BusinessAcquisitionPercentageOfVotingInterestsAcquired dei:LegalEntity, us-gaap:BusinessAcquisition

us-gaap:BusinessAcquisitionPercentageOfVotingInterestsAcquired

swn:IndigoNaturalResourcesLLC, swn:IndigoNaturalResourcesLLC


Business
Period End2021-06-01
Value33.0
Percentage of BusinessAcquisitionPercentageOfVotingInterestsAcquired100.0

us-gaap:BusinessAcquisitionPercentageOfVotingInterestsAcquired us-gaap:BusinessAcquisition

swn:IndigoNaturalResourcesLLC


Business
Period End2021-06-01
Value67.0
Percentage of BusinessAcquisitionPercentageOfVotingInterestsAcquired203.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value1244
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value3000000.0
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value1000000.0
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value73
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value145
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value49
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value70
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedFinancialLiabilities100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value1031
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt us-gaap:StatementScenario, us-gaap:BusinessAcquisition, us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt

srt:ScenarioForecast, swn:IndigoNaturalResourcesLLC, swn:A5375SeniorNotesDue2029, us-gaap:SeniorNotes


Business
Period End2021-12-31
Value700
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value17
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value26
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets100.0

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet us-gaap:BusinessAcquisition

us-gaap:BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet

swn:MontageResourcesCorporation


Business
Period End2020-11-13
Value213
Percentage of BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet100.0

us-gaap:CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities

us-gaap:CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities


Capitalized
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
Value2336220203197611928718897162488327748167744092-3444.477-2916.947
Percentage of CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative

us-gaap:CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative


Capitalized
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value1485148814721379142314371506151816781673175517671835182218171919203420782105218933823505372749024819499746461037958957
Percentage of CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative us-gaap:BusinessAcquisition

swn:MontageResourcesCorporation


Capitalized
Period End2020-12-31
Value88
Percentage of CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative6.0

us-gaap:CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative us-gaap:StatementGeographical

swn:UndevelopedPropertiesNortheastAppalachia


Capitalized
Period End2020-12-312019-12-31
Value6.010.0
Percentage of CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative0.40.7

swn:UndevelopedPropertiesSouthwestAppalachia


Capitalized
Period End2020-12-312019-12-31
Value11001200
Percentage of CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative74.779.7

swn:WellsInProgress


Capitalized
Period End2020-12-312019-12-31
Value6195
Percentage of CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortizationCumulative4.16.3

us-gaap:CapitalizedCostsOilAndGasProducingActivitiesGross

us-gaap:CapitalizedCostsOilAndGasProducingActivitiesGross


Capitalized
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
Value272612525024180238902265322478205061329311283954477496329
Percentage of CapitalizedCostsOilAndGasProducingActivitiesGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CapitalizedCostsOilAndGasProducingActivitiesNet

us-gaap:CapitalizedCostsOilAndGasProducingActivitiesNet


Capitalized
Period End2020-12-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312012-09-302012-06-302011-12-312010-12-312009-12-31
Value3899504744194603375662301217958124508185496545243053412
Percentage of CapitalizedCostsOilAndGasProducingActivitiesNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CapitalizedCostsProvedProperties

us-gaap:CapitalizedCostsProvedProperties


Capitalized
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
Value257892374422425220732054818751158601233710259860170375733
Percentage of CapitalizedCostsProvedProperties100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CapitalizedCostsUnprovedProperties

us-gaap:CapitalizedCostsUnprovedProperties


Capitalized
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
Value14721506175518172105372746469561023942712595
Percentage of CapitalizedCostsUnprovedProperties100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CashAndCashEquivalentsFairValueDisclosure us-gaap:FairValueByMeasurementBasis

us-gaap:CashAndCashEquivalentsFairValueDisclosure

us-gaap:CarryingReportedAmountFairValueDisclosure


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value2.04.0139510.05.05.0291553662019.03795891698911111382142314749981597151537175320201822182553
Percentage of CashAndCashEquivalentsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EstimateOfFairValueFairValueDisclosure


Cash
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-31
Value2.04.0139510.05.05.0291553662019.03795891698911111382142314749981597151537175320201822182553
Percentage of CashAndCashEquivalentsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent

us-gaap:ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent


Contract
Period End2020-12-312019-12-31
Value350284
Percentage of ContractWithCustomerReceivableAfterAllowanceForCreditLossCurrent100.0100.0

us-gaap:DebtInstrumentCarryingAmount

us-gaap:DebtInstrumentCarryingAmount


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value30393038317124712457229722622292234223422342443344734408465946844685580764694733
Percentage of DebtInstrumentCarryingAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtInstrumentCarryingAmount us-gaap:CreditFacility, us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:RevolvingCreditFacility, swn:A2018RevolvingCreditFacility, us-gaap:LineOfCredit


Debt
Period End2021-06-302021-03-312020-12-312019-12-31
Value56856770034
Percentage of DebtInstrumentCarryingAmount18.718.722.11.5

us-gaap:DebtInstrumentCarryingAmount us-gaap:DebtInstrument, us-gaap:LongtermDebtType

swn:A2018TermLoanFacility, us-gaap:LineOfCredit


Debt
Period End2020-12-312018-12-31
Value7000.0
Percentage of DebtInstrumentCarryingAmount22.10.0

swn:FourPointNineFivePercentSeniorNotesDueJanuary2025, us-gaap:SeniorNotes


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value856856856856856864892927
Percentage of DebtInstrumentCarryingAmount28.228.227.034.634.837.639.439.6

swn:FourPointOnePercentSeniorNotesDueMarch2022, us-gaap:SeniorNotes


Debt
Period End2020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value207207207210213213
Percentage of DebtInstrumentCarryingAmount6.58.48.49.19.49.1

swn:SevenPointFivePercentSeniorNotesDueApril2026, us-gaap:SeniorNotes


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value618618618618618621639650
Percentage of DebtInstrumentCarryingAmount20.320.319.525.025.227.028.227.8

swn:SevenPointSevenFivePercentSeniorNotesDueOctober2027, us-gaap:SeniorNotes


Debt
Period End2021-06-302021-03-312020-12-312020-09-302020-06-302020-03-312019-12-312018-12-31
Value440440440440440453484500
Percentage of DebtInstrumentCarryingAmount14.514.513.917.817.919.721.421.3

us-gaap:DebtInstrumentCarryingAmount us-gaap:LongtermDebtType

us-gaap:LongTermDebt


Debt
Period End2021-06-302021-03-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-31
Value28322831360236024433443344334368439346434684580664684732
Percentage of DebtInstrumentCarryingAmount93.293.20.00.00.0100.099.199.194.399.1100.0100.0100.0100.0

us-gaap:DebtInstrumentRepurchasedFaceAmount us-gaap:DebtInstrument, us-gaap:LongtermDebtType

us-gaap:DebtInstrumentRepurchasedFaceAmount

swn:FourPointNineFivePercentSeniorNotesDueJanuary2025, us-gaap:SeniorNotes


Debt
Period End2020-09-302020-06-302020-03-312019-12-312018-12-31
Value3636283573
Percentage of DebtInstrumentRepurchasedFaceAmount100.0100.0100.0100.0100.0

swn:FourPointOnePercentSeniorNotesDueMarch2022, us-gaap:SeniorNotes


Debt
Period End2020-09-302020-06-302020-03-312018-12-31
Value6.06.03.0787
Percentage of DebtInstrumentRepurchasedFaceAmount16.716.710.71078.1

swn:FourPointZeroFivePercentSeniorNotesDueJanuary2020, us-gaap:SeniorNotes


Debt
Period End2020-09-302020-06-302020-03-312018-12-31
Value72725240
Percentage of DebtInstrumentRepurchasedFaceAmount200.0200.0185.754.8

swn:SevenPointFivePercentSeniorNotesDueApril2026, us-gaap:SeniorNotes


Debt
Period End2020-09-302020-06-302020-03-312019-12-31
Value21211811
Percentage of DebtInstrumentRepurchasedFaceAmount58.358.364.331.4

swn:SevenPointSevenFivePercentSeniorNotesDueOctober2027, us-gaap:SeniorNotes


Debt