false--12-31Q220190000007332SOUTHWESTERN ENERGY CO0.01750.01750.00250.00251P60DP30DP60DP30DP60DP30D175500000016780000000.010.011250000000125000000058540710758547834500.039200.038800.04950.07750.0410.04050.075105000000300000010000002000000P3YP4YP3Y3909253744353224 0000007332 2019-01-01 2019-06-30 0000007332 2019-08-02 0000007332 us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-01-01 2018-06-30 0000007332 2018-04-01 2018-06-30 0000007332 2019-04-01 2019-06-30 0000007332 swn:GasGatheringMember 2019-01-01 2019-06-30 0000007332 swn:MarketingMember 2019-01-01 2019-06-30 0000007332 2018-01-01 2018-06-30 0000007332 swn:MarketingMember 2019-04-01 2019-06-30 0000007332 swn:OtherMember 2019-04-01 2019-06-30 0000007332 swn:GasGatheringMember 2018-04-01 2018-06-30 0000007332 swn:NaturalGasLiquidsSalesMember 2019-01-01 2019-06-30 0000007332 swn:OilSalesMember 2019-01-01 2019-06-30 0000007332 swn:GasGatheringMember 2018-01-01 2018-06-30 0000007332 swn:GasSalesMember 2019-01-01 2019-06-30 0000007332 us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-04-01 2019-06-30 0000007332 us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-04-01 2018-06-30 0000007332 swn:GasSalesMember 2018-04-01 2018-06-30 0000007332 swn:NaturalGasLiquidsSalesMember 2018-04-01 2018-06-30 0000007332 swn:MarketingMember 2018-01-01 2018-06-30 0000007332 swn:GasSalesMember 2019-04-01 2019-06-30 0000007332 swn:OtherMember 2018-01-01 2018-06-30 0000007332 swn:OilSalesMember 2018-01-01 2018-06-30 0000007332 us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-01-01 2019-06-30 0000007332 swn:OilSalesMember 2018-04-01 2018-06-30 0000007332 swn:MarketingMember 2018-04-01 2018-06-30 0000007332 swn:GasGatheringMember 2019-04-01 2019-06-30 0000007332 swn:OtherMember 2018-04-01 2018-06-30 0000007332 swn:NaturalGasLiquidsSalesMember 2018-01-01 2018-06-30 0000007332 swn:OtherMember 2019-01-01 2019-06-30 0000007332 swn:NaturalGasLiquidsSalesMember 2019-04-01 2019-06-30 0000007332 swn:OilSalesMember 2019-04-01 2019-06-30 0000007332 swn:GasSalesMember 2018-01-01 2018-06-30 0000007332 2018-12-31 0000007332 2019-06-30 0000007332 2018-06-30 0000007332 2017-12-31 0000007332 us-gaap:CommonStockMember 2018-04-01 2018-06-30 0000007332 us-gaap:AdditionalPaidInCapitalMember 2018-06-30 0000007332 us-gaap:RetainedEarningsMember 2018-04-01 2018-06-30 0000007332 2018-01-01 2018-03-31 0000007332 us-gaap:RetainedEarningsMember 2018-03-31 0000007332 us-gaap:CommonStockMember 2017-12-31 0000007332 us-gaap:CommonStockMember 2018-01-01 2018-03-31 0000007332 us-gaap:CommonStockMember 2018-06-30 0000007332 2018-03-31 0000007332 us-gaap:AdditionalPaidInCapitalMember 2018-01-01 2018-03-31 0000007332 us-gaap:TreasuryStockMember 2017-12-31 0000007332 us-gaap:AdditionalPaidInCapitalMember 2018-04-01 2018-06-30 0000007332 us-gaap:TreasuryStockMember 2018-06-30 0000007332 us-gaap:AdditionalPaidInCapitalMember 2017-12-31 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-03-31 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2017-12-31 0000007332 us-gaap:PreferredStockMember 2017-12-31 0000007332 us-gaap:RetainedEarningsMember 2018-06-30 0000007332 us-gaap:RetainedEarningsMember 2017-12-31 0000007332 us-gaap:TreasuryStockMember 2018-03-31 0000007332 us-gaap:PreferredStockMember 2018-01-01 2018-03-31 0000007332 us-gaap:RetainedEarningsMember 2018-01-01 2018-03-31 0000007332 us-gaap:PreferredStockMember 2018-03-31 0000007332 us-gaap:CommonStockMember 2018-03-31 0000007332 us-gaap:AdditionalPaidInCapitalMember 2018-03-31 0000007332 us-gaap:PreferredStockMember 2018-06-30 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-06-30 0000007332 us-gaap:CommonStockMember 2019-03-31 0000007332 us-gaap:TreasuryStockMember 2018-12-31 0000007332 2019-01-01 2019-03-31 0000007332 us-gaap:CommonStockMember 2019-04-01 2019-06-30 0000007332 us-gaap:AdditionalPaidInCapitalMember 2019-03-31 0000007332 us-gaap:CommonStockMember 2018-12-31 0000007332 us-gaap:CommonStockMember 2019-01-01 2019-03-31 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-03-31 0000007332 us-gaap:TreasuryStockMember 2019-01-01 2019-03-31 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-04-01 2019-06-30 0000007332 us-gaap:AdditionalPaidInCapitalMember 2019-04-01 2019-06-30 0000007332 us-gaap:TreasuryStockMember 2019-03-31 0000007332 us-gaap:CommonStockMember 2019-06-30 0000007332 us-gaap:RetainedEarningsMember 2018-12-31 0000007332 us-gaap:TreasuryStockMember 2019-06-30 0000007332 us-gaap:AdditionalPaidInCapitalMember 2019-06-30 0000007332 us-gaap:RetainedEarningsMember 2019-03-31 0000007332 2019-03-31 0000007332 us-gaap:RetainedEarningsMember 2019-06-30 0000007332 us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-06-30 0000007332 us-gaap:AdditionalPaidInCapitalMember 2019-01-01 2019-03-31 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-12-31 0000007332 us-gaap:RetainedEarningsMember 2019-04-01 2019-06-30 0000007332 us-gaap:RetainedEarningsMember 2019-01-01 2019-03-31 0000007332 swn:FayettevilleShaleMember 2018-08-30 0000007332 2018-12-01 2018-12-31 0000007332 swn:NonCoreLeaseholdMember 2019-06-30 0000007332 swn:FayettevilleShaleMember 2018-12-03 2018-12-03 0000007332 us-gaap:SeniorNotesMember 2018-12-01 2018-12-31 0000007332 swn:FayettevilleShaleMember 2018-08-30 2018-08-30 0000007332 us-gaap:OtherRestructuringMember 2019-01-01 2019-06-30 0000007332 us-gaap:OtherRestructuringMember 2018-12-31 0000007332 us-gaap:OtherRestructuringMember 2019-06-30 0000007332 us-gaap:OtherRestructuringMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OtherRestructuringMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OtherRestructuringMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:OtherRestructuringMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OtherRestructuringMember 2018-01-01 2018-06-30 0000007332 us-gaap:OtherRestructuringMember 2018-04-01 2018-06-30 0000007332 us-gaap:OtherRestructuringMember 2019-04-01 2019-06-30 0000007332 us-gaap:AccountingStandardsUpdate201602Member 2019-01-01 0000007332 us-gaap:IntersegmentEliminationMember swn:GasSalesMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OtherMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:GasGatheringMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:OilSalesMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:OilSalesMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OtherMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OtherMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasGatheringMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:OtherMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:NaturalGasLiquidsSalesMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:GasSalesMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:NaturalGasLiquidsSalesMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:OtherMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OtherMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasGatheringMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:SouthwestAppalachiaMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NortheastAppalachiaMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember srt:OtherPropertyMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NortheastAppalachiaMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:SouthwestAppalachiaMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:SouthwestAppalachiaMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NortheastAppalachiaMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NortheastAppalachiaMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember srt:OtherPropertyMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:FayettevilleShaleMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember srt:OtherPropertyMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember srt:OtherPropertyMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:FayettevilleShaleMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:SouthwestAppalachiaMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:FayettevilleShaleMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:FayettevilleShaleMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 swn:FayettevilleShaleMember 2018-12-01 2018-12-31 0000007332 us-gaap:OperatingSegmentsMember swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasGatheringMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:GasGatheringMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:OtherMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasGatheringMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:OilSalesMember 2019-04-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:GasSalesMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OtherMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OilSalesMember swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:GasSalesMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:NaturalGasLiquidsSalesMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:MarketingMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:NaturalGasLiquidsSalesMember 2019-04-01 2019-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:OtherMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:OilSalesMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:NaturalGasLiquidsSalesMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:OperatingSegmentsMember swn:GasSalesMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 swn:NaturalGasLiquidsSalesMember srt:MinimumMember 2019-01-01 2019-06-30 0000007332 swn:MarketingMember srt:MinimumMember 2019-01-01 2019-06-30 0000007332 swn:NaturalGasLiquidsSalesMember srt:MaximumMember 2019-01-01 2019-06-30 0000007332 swn:MarketingMember srt:MaximumMember 2019-01-01 2019-06-30 0000007332 swn:GasGatheringMember srt:MaximumMember 2019-01-01 2019-06-30 0000007332 swn:GasGatheringMember srt:MinimumMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:HenryHubMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasLiquidsReservesMember swn:WestTexasIntermediateMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:WestTexasIntermediateMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:WestTexasIntermediateMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:HenryHubMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasLiquidsReservesMember swn:WestTexasIntermediateMember 2018-01-01 2018-06-30 0000007332 us-gaap:EmployeeStockOptionMember 2018-04-01 2018-06-30 0000007332 us-gaap:EmployeeStockOptionMember 2019-01-01 2019-06-30 0000007332 swn:MandatoryConvertiblePreferredStockMember 2019-04-01 2019-06-30 0000007332 us-gaap:PerformanceSharesMember 2019-01-01 2019-06-30 0000007332 swn:UnvestedShareBasedPaymentMember 2019-04-01 2019-06-30 0000007332 swn:UnvestedShareBasedPaymentMember 2019-01-01 2019-06-30 0000007332 us-gaap:PerformanceSharesMember 2018-04-01 2018-06-30 0000007332 swn:MandatoryConvertiblePreferredStockMember 2018-01-01 2018-06-30 0000007332 swn:UnvestedShareBasedPaymentMember 2018-01-01 2018-06-30 0000007332 swn:MandatoryConvertiblePreferredStockMember 2019-01-01 2019-06-30 0000007332 us-gaap:EmployeeStockOptionMember 2019-04-01 2019-06-30 0000007332 us-gaap:EmployeeStockOptionMember 2018-01-01 2018-06-30 0000007332 swn:UnvestedShareBasedPaymentMember 2018-04-01 2018-06-30 0000007332 us-gaap:PerformanceSharesMember 2018-01-01 2018-06-30 0000007332 us-gaap:PerformanceSharesMember 2019-04-01 2019-06-30 0000007332 swn:MandatoryConvertiblePreferredStockMember 2018-04-01 2018-06-30 0000007332 2018-07-01 2018-12-31 0000007332 swn:DepositarySharesMember 2015-01-01 2015-01-31 0000007332 us-gaap:CommonStockMember 2018-01-12 0000007332 swn:DepositarySharesMember 2018-01-01 2018-01-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:PurchasedCallOptionsMember us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 us-gaap:CommodityContractMember 2019-06-30 0000007332 us-gaap:InterestRateSwapMember 2019-06-30 0000007332 srt:OilReservesMember swn:SoldFixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember 2018-01-01 2018-06-30 0000007332 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:SoldFixedPriceSwapsMember us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:FixedPriceSwapStorage2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:PurchasedFixedPriceSwapsStorage2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:PurchasedBasisSwapsStorage2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PurchasedFixedPriceSwapsStorage2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:Storage2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PurchasedBasisSwapsStorage2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:FixedPriceSwapStorage2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:Storage2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember swn:DerivativeAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:EthaneMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:DerivativeAssetsMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:PropaneMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:PurchasedCallOptionsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember swn:DerivativeAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:PropaneMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:EthaneMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:EthaneMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:PropaneMember swn:DerivativeAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:DerivativeAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:DerivativeAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember swn:PurchasedCallOptionsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeAssetsMember swn:PurchasedCallOptionsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:DerivativeAssetsMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:DerivativeAssetsMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:EthaneMember swn:DerivativeAssetsMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentAssetsMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentAssetsMember swn:PurchasedCallOptionsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:BasisSwap2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsSoldPuts2021Member us-gaap:NondesignatedMember us-gaap:ShortMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:Derivative2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:Derivative2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollars2021Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollars2021Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsSoldCalls2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:BasisSwap2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsSoldCalls2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:BasisSwap2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsSoldPuts2019Member us-gaap:NondesignatedMember us-gaap:ShortMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldBasisSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:BasisSwap2021Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsSoldCalls2021Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsPurchasePuts2019Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsSoldPuts2020Member us-gaap:NondesignatedMember us-gaap:ShortMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:Derivative2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsPurchasedPuts2019Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsPurchasedPuts2020Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:BasisSwap2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:BasisSwap2021Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsSoldCalls2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsPurchasedPuts2021Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:Derivative2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldBasisSwapsMember us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsSoldPuts2019Member us-gaap:NondesignatedMember us-gaap:ShortMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsPurchasedPuts2020Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsSoldCalls2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:Derivative2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsPurchasedPuts2020Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsSoldCalls2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsPurchasedPuts2020Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:PropaneMember swn:Derivative2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsSoldCalls2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsSoldCalls2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:Derivative2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsPurchasePuts2019Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsSoldPuts2020Member us-gaap:NondesignatedMember us-gaap:ShortMember 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwaps2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:Derivative2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsSoldCalls2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwaps2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:Derivative2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:Derivative2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsSoldCalls2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsPurchasedPuts2019Member us-gaap:NondesignatedMember us-gaap:LongMember 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsPurchasedPuts2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollars2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollars2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:Derivative2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 swn:PropaneMember swn:Derivative2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:SoldCallOptionsMember 2019-04-01 2019-06-30 0000007332 us-gaap:InterestRateSwapMember 2018-04-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember 2019-04-01 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember 2019-04-01 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember 2018-01-01 2018-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember 2018-01-01 2018-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember 2019-04-01 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember 2019-04-01 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember 2019-04-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember 2019-04-01 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember 2019-04-01 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember 2018-01-01 2018-06-30 0000007332 swn:StorageFixedPriceSwapMember 2019-04-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember 2019-01-01 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember 2018-01-01 2018-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:SoldCallOptionsMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:SoldCallOptionsMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember 2019-04-01 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember 2018-04-01 2018-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember 2018-01-01 2018-06-30 0000007332 us-gaap:InterestRateSwapMember 2018-01-01 2018-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember 2018-04-01 2018-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember 2018-04-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember 2018-04-01 2018-06-30 0000007332 us-gaap:InterestRateSwapMember 2019-04-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember 2018-04-01 2018-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember 2018-04-01 2018-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember 2019-04-01 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember 2018-04-01 2018-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember 2018-01-01 2018-06-30 0000007332 us-gaap:InterestRateSwapMember 2019-01-01 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:SoldCallOptionsMember 2018-04-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember 2018-04-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember 2018-04-01 2018-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember 2019-04-01 2019-06-30 0000007332 swn:StorageFixedPriceSwapMember 2018-04-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember 2018-01-01 2018-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember 2019-04-01 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember 2018-04-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember 2018-04-01 2018-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember 2019-01-01 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember 2019-04-01 2019-06-30 0000007332 swn:StorageFixedPriceSwapMember 2018-01-01 2018-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember 2018-04-01 2018-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember 2018-04-01 2018-06-30 0000007332 swn:StorageFixedPriceSwapMember 2019-01-01 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember 2019-04-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptions2021Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptions2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptions2021Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptions2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptions2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptions2021Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptions2019Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptions2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptions2020Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptions2020Member us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptions2021Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptions2019Member us-gaap:NondesignatedMember 2019-01-01 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:DerivativeLiabilitiesMember swn:PurchasedFixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember swn:DerivativeLiabilitiesMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:SoldCallOptionsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:DerivativeLiabilitiesMember swn:StorageFixedPriceSwapMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember swn:DerivativeLiabilitiesMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:SoldCallOptionsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:SoldCallOptionsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:DerivativeLiabilitiesMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 swn:DerivativeLiabilitiesMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:DerivativeLiabilitiesMember swn:StorageFixedPriceSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:OilReservesMember swn:DerivativeLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:OtherNoncurrentLiabilitiesMember us-gaap:BasisSwapMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:EthaneMember swn:DerivativeLiabilitiesMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:DerivativeLiabilitiesMember swn:SoldCallOptionsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 swn:EthaneMember swn:DerivativeLiabilitiesMember swn:FixedPriceSwapsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember us-gaap:OtherNoncurrentLiabilitiesMember swn:TwoWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:DerivativeLiabilitiesMember swn:ThreeWayCostlessCollarsMember us-gaap:NondesignatedMember 2019-06-30 0000007332 srt:OilReservesMember swn:DerivativeLiabilitiesMember swn:PurchasedFixedPriceSwapsMember us-gaap:NondesignatedMember 2018-12-31 0000007332 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember 2019-01-01 2019-06-30 0000007332 us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-06-30 0000007332 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-06-30 0000007332 us-gaap:AccumulatedTranslationAdjustmentMember 2018-12-31 0000007332 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2019-01-01 2019-06-30 0000007332 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2018-12-31 0000007332 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember 2019-06-30 0000007332 us-gaap:AccumulatedTranslationAdjustmentMember 2019-01-01 2019-06-30 0000007332 us-gaap:AccumulatedTranslationAdjustmentMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 swn:StorageFixedPriceSwapMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 swn:StorageFixedPriceSwapMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember 2019-06-30 0000007332 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:OilReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 swn:StorageFixedPriceSwapMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember 2019-06-30 0000007332 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember 2019-06-30 0000007332 swn:PropaneMember swn:TwoWayCostlessCollarsMember 2019-06-30 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 swn:StorageFixedPriceSwapMember us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember 2019-06-30 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2019-06-30 0000007332 us-gaap:FairValueInputsLevel1Member 2019-06-30 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2019-06-30 0000007332 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000007332 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-06-30 0000007332 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2018-12-31 0000007332 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-06-30 0000007332 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2018-12-31 0000007332 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:CreditFacilityFourMember us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:LongTermDebtMember 2019-06-30 0000007332 swn:CreditFacilityFourMember us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:LongTermDebtMember 2019-06-30 0000007332 swn:CreditFacilityFourMember us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:LongTermDebtMember 2018-12-31 0000007332 swn:CreditFacilityFourMember us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:LongTermDebtMember 2018-12-31 0000007332 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:SeniorNotesMember 2018-12-31 0000007332 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:SeniorNotesSixMember us-gaap:LongTermDebtMember 2015-01-31 0000007332 srt:NaturalGasReservesMember us-gaap:CallOptionMember 2018-01-01 2018-06-30 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember 2018-12-31 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember 2018-12-31 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 swn:EthaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember 2018-12-31 0000007332 us-gaap:InterestRateSwapMember 2018-12-31 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:FairValueInputsLevel2Member 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember 2018-12-31 0000007332 srt:OilReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 swn:PropaneMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:ThreeWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 us-gaap:InterestRateSwapMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:TwoWayCostlessCollarsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember 2018-12-31 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:OilReservesMember swn:FixedPriceSwapsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:PurchasedCallOptionsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:NaturalGasReservesMember us-gaap:BasisSwapMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 srt:NaturalGasReservesMember swn:SoldCallOptionsMember us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 us-gaap:FairValueInputsLevel3Member 2018-12-31 0000007332 srt:OilReservesMember swn:PurchasedFixedPriceSwapsMember us-gaap:FairValueInputsLevel1Member 2018-12-31 0000007332 swn:SeniorNotesEightMember us-gaap:SeniorNotesMember 2018-12-31 0000007332 swn:SeniorNotesTenMember us-gaap:SeniorNotesMember 2018-12-31 0000007332 swn:SeniorNotesSevenMember us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:A2018TermLoanFacilityMember us-gaap:LineOfCreditMember 2018-12-31 0000007332 swn:SeniorNotesSixMember us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:A2018RevolvingCreditFacilityMember us-gaap:LineOfCreditMember 2019-06-30 0000007332 us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:SeniorNotesElevenMember us-gaap:SeniorNotesMember 2018-12-31 0000007332 swn:SeniorNotesSixMember us-gaap:SeniorNotesMember 2018-12-31 0000007332 swn:SeniorNotesEightMember us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:SeniorNotesElevenMember us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:SeniorNotesTenMember us-gaap:SeniorNotesMember 2019-06-30 0000007332 swn:SeniorNotesSevenMember us-gaap:SeniorNotesMember 2018-12-31 0000007332 srt:MinimumMember swn:CreditFacilityFourMember us-gaap:LongTermDebtMember us-gaap:EurodollarMember 2018-04-01 2018-04-30 0000007332 srt:MaximumMember swn:AfterJune302020Member swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2018-04-01 2018-04-30 0000007332 srt:MinimumMember swn:CreditFacilityFourMember us-gaap:LongTermDebtMember us-gaap:BaseRateMember 2018-04-01 2018-04-30 0000007332 swn:SeniorNotesSixMember us-gaap:LongTermDebtMember 2016-07-31 0000007332 swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2019-06-30 0000007332 us-gaap:LetterOfCreditMember 2019-06-30 0000007332 swn:SeniorNotesSixMember us-gaap:LongTermDebtMember 2018-07-31 0000007332 swn:SeniorNotesEightMember us-gaap:LongTermDebtMember 2019-06-30 0000007332 swn:SeniorNotesEightMember us-gaap:LongTermDebtMember 2018-07-31 0000007332 swn:CreditFacilityTwoMember us-gaap:LongTermDebtMember 2018-04-30 0000007332 srt:MaximumMember swn:CreditFacilityFourMember us-gaap:LongTermDebtMember us-gaap:EurodollarMember 2018-04-01 2018-04-30 0000007332 us-gaap:OtherNoncurrentAssetsMember swn:A2018RevolvingCreditFacilityMember us-gaap:LineOfCreditMember 2018-12-31 0000007332 swn:SecuredTermLoanMember us-gaap:LongTermDebtMember 2018-04-26 2018-04-26 0000007332 srt:MaximumMember swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2018-04-01 2018-04-30 0000007332 swn:SecuredTermLoanMember us-gaap:LongTermDebtMember 2018-04-26 0000007332 swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2019-04-04 0000007332 swn:SeniorNotesEightMember us-gaap:LongTermDebtMember 2015-01-31 0000007332 swn:TermLoanThreeMember us-gaap:LongTermDebtMember 2018-04-30 0000007332 us-gaap:OtherNoncurrentAssetsMember swn:A2018RevolvingCreditFacilityMember us-gaap:LineOfCreditMember 2019-06-30 0000007332 swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2018-04-01 2018-04-30 0000007332 swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2018-04-30 0000007332 swn:SeniorNotesEightMember us-gaap:LongTermDebtMember 2016-07-31 0000007332 srt:MaximumMember swn:CreditFacilityFourMember us-gaap:LongTermDebtMember us-gaap:BaseRateMember 2018-04-01 2018-04-30 0000007332 srt:MaximumMember swn:June302018ThroughMarch312019Member swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2018-04-01 2018-04-30 0000007332 swn:SeniorNotesSixMember us-gaap:LongTermDebtMember 2019-06-30 0000007332 srt:MaximumMember swn:June302019ThroughMarch312020Member swn:CreditFacilityFourMember us-gaap:LongTermDebtMember 2018-04-01 2018-04-30 0000007332 us-gaap:SeniorNotesMember us-gaap:LondonInterbankOfferedRateLIBORMember 2016-07-01 2016-07-31 0000007332 us-gaap:SeniorNotesMember us-gaap:LondonInterbankOfferedRateLIBORMember 2015-01-01 2015-01-31 0000007332 us-gaap:SeniorNotesMember us-gaap:LondonInterbankOfferedRateLIBORMember 2016-02-01 2016-02-29 0000007332 swn:A2018TermLoanFacilityMember us-gaap:LineOfCreditMember 2018-01-01 2018-12-31 0000007332 swn:A2018RevolvingCreditFacilityMember us-gaap:LineOfCreditMember 2019-01-01 2019-06-30 0000007332 swn:AppalachianBasinMember 2019-03-31 0000007332 swn:ArkansasRoyaltyLitigationMember 2019-06-30 0000007332 us-gaap:SubsequentEventMember 2019-07-31 0000007332 swn:ArkansasRoyaltyLitigationMember stpr:AR 2019-06-30 0000007332 swn:PendingRegulatoryApprovalAndOrConstructionMember 2019-06-30 0000007332 swn:InfrastructureCurrentlyInServiceMember 2019-06-30 0000007332 swn:ArkansasRoyaltyLitigationMember swn:EasternArkansasMember 2019-06-30 0000007332 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-06-30 0000007332 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000007332 us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-06-30 0000007332 us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2019-01-01 2019-06-30 0000007332 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-12-31 0000007332 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2018-01-01 2018-06-30 0000007332 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-06-30 0000007332 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-04-01 2019-06-30 0000007332 us-gaap:SupplementalEmployeeRetirementPlanDefinedBenefitMember 2018-01-01 2018-12-31 0000007332 us-gaap:PensionPlansDefinedBenefitMember 2019-06-30 0000007332 us-gaap:PensionPlansDefinedBenefitMember 2018-12-31 0000007332 us-gaap:PensionPlansDefinedBenefitMember 2018-01-01 2018-06-30 0000007332 us-gaap:PensionPlansDefinedBenefitMember 2019-04-01 2019-06-30 0000007332 us-gaap:PensionPlansDefinedBenefitMember 2018-04-01 2018-06-30 0000007332 us-gaap:EmployeeStockOptionMember 2018-12-31 0000007332 us-gaap:EmployeeStockOptionMember 2019-06-30 0000007332 us-gaap:EmployeeStockOptionMember 2019-01-01 2019-06-30 0000007332 us-gaap:RestrictedStockUnitsRSUMember 2019-01-01 2019-06-30 0000007332 us-gaap:RestrictedStockUnitsRSUMember 2018-12-31 0000007332 us-gaap:RestrictedStockUnitsRSUMember 2019-06-30 0000007332 us-gaap:RestrictedStockMember 2019-06-30 0000007332 us-gaap:RestrictedStockMember 2018-12-31 0000007332 us-gaap:RestrictedStockMember 2019-01-01 2019-06-30 0000007332 us-gaap:PerformanceSharesMember 2019-01-01 2019-06-30 0000007332 us-gaap:PerformanceSharesMember 2018-12-31 0000007332 us-gaap:PerformanceSharesMember 2019-06-30 0000007332 srt:MaximumMember us-gaap:PerformanceSharesMember 2019-01-01 2019-06-30 0000007332 us-gaap:RestrictedStockUnitsRSUMember 2019-04-01 2019-06-30 0000007332 srt:MinimumMember us-gaap:PerformanceSharesMember 2019-01-01 2019-06-30 0000007332 us-gaap:PerformanceSharesMember 2018-04-01 2018-06-30 0000007332 us-gaap:PerformanceSharesMember 2019-04-01 2019-06-30 0000007332 us-gaap:RestrictedStockUnitsRSUMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 swn:ExplorationAndProductionMember 2019-06-30 0000007332 us-gaap:CorporateAndOtherMember 2019-04-01 2019-06-30 0000007332 us-gaap:CorporateAndOtherMember 2018-04-01 2018-06-30 0000007332 swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 us-gaap:CorporateAndOtherMember 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember us-gaap:CorporateAndOtherMember 2019-04-01 2019-06-30 0000007332 swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 swn:MidstreamServicesMember 2018-06-30 0000007332 swn:ExplorationAndProductionMember 2018-04-01 2018-06-30 0000007332 us-gaap:CorporateAndOtherMember 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember us-gaap:CorporateAndOtherMember 2018-04-01 2018-06-30 0000007332 swn:ExplorationAndProductionMember 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:ExplorationAndProductionMember 2019-04-01 2019-06-30 0000007332 swn:MidstreamServicesMember 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 swn:NonCoreGatheringAssetsMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember swn:MidstreamServicesMember 2019-04-01 2019-06-30 0000007332 swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember swn:MidstreamServicesMember 2018-04-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MarketingMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:CorporateAndOtherMember 2019-01-01 2019-06-30 0000007332 us-gaap:CorporateAndOtherMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MidstreamServicesMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:MidstreamServicesMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:ExplorationAndProductionMember 2019-01-01 2019-06-30 0000007332 us-gaap:IntersegmentEliminationMember swn:ExplorationAndProductionMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember us-gaap:CorporateAndOtherMember 2018-01-01 2018-06-30 0000007332 us-gaap:IntersegmentEliminationMember us-gaap:CorporateAndOtherMember 2019-01-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember 2019-01-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:OtherMember 2019-01-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember 2019-01-01 2019-06-30 0000007332 srt:ParentCompanyMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:NaturalGasLiquidsSalesMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember 2019-01-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:OtherMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-01-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:MarketingMember 2019-01-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:OilSalesMember 2019-01-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:MarketingMember 2019-01-01 2019-06-30 0000007332 srt:ParentCompanyMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-01-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-01-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:MarketingMember 2019-01-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:OtherMember 2019-01-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:GasSalesMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:GasSalesMember 2019-01-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:OilSalesMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:OtherMember 2019-01-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:NaturalGasLiquidsSalesMember 2019-01-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2019-01-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:MarketingMember 2019-01-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:GasSalesMember 2019-01-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:OilSalesMember 2019-01-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:OilSalesMember 2019-01-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:GasSalesMember 2019-01-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember 2018-01-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember 2017-12-31 0000007332 srt:ConsolidationEliminationsMember 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember 2018-06-30 0000007332 srt:ParentCompanyMember 2018-06-30 0000007332 srt:ConsolidationEliminationsMember 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember 2017-12-31 0000007332 srt:ParentCompanyMember 2018-12-31 0000007332 srt:NonGuarantorSubsidiariesMember 2018-12-31 0000007332 srt:ConsolidationEliminationsMember 2018-12-31 0000007332 srt:ParentCompanyMember 2017-12-31 0000007332 srt:ParentCompanyMember 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember 2018-12-31 0000007332 srt:GuarantorSubsidiariesMember 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember 2017-12-31 0000007332 srt:NonGuarantorSubsidiariesMember 2019-06-30 0000007332 srt:ConsolidationEliminationsMember 2019-04-01 2019-06-30 0000007332 srt:ParentCompanyMember 2019-04-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:GasSalesMember 2019-04-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember 2019-04-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:MarketingMember 2019-04-01 2019-06-30 0000007332 srt:ParentCompanyMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-04-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:MarketingMember 2019-04-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember 2019-04-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-04-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:NaturalGasLiquidsSalesMember 2019-04-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:OilSalesMember 2019-04-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:MarketingMember 2019-04-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:OilSalesMember 2019-04-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:GasSalesMember 2019-04-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:NaturalGasLiquidsSalesMember 2019-04-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-04-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2019-04-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2019-04-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:OilSalesMember 2019-04-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:OilSalesMember 2019-04-01 2019-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2019-04-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:MarketingMember 2019-04-01 2019-06-30 0000007332 srt:ParentCompanyMember swn:GasSalesMember 2019-04-01 2019-06-30 0000007332 srt:ConsolidationEliminationsMember swn:GasSalesMember 2019-04-01 2019-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:OtherMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:GasGatheringMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:NaturalGasLiquidsSalesMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:GasSalesMember 2018-01-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:GasGatheringMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:OtherMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:MarketingMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:NaturalGasLiquidsSalesMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:MarketingMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:GasSalesMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:GasSalesMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:MarketingMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:OtherMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:OtherMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-01-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:MarketingMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:OilSalesMember 2018-01-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:GasGatheringMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-01-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:OilSalesMember 2018-01-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:GasSalesMember 2018-01-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:OilSalesMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:GasGatheringMember 2018-01-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:OilSalesMember 2018-01-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2018-01-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:MarketingMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:OtherMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:OtherMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:OilSalesMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:OtherMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:GasGatheringMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:OilSalesMember 2018-04-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:GasSalesMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-04-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:NaturalGasLiquidsSalesMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:OilSalesMember 2018-04-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:GasGatheringMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:GasSalesMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2018-04-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:MarketingMember 2018-04-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:OtherMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:GasGatheringMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:MarketingMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:MarketingMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:NaturalGasLiquidsSalesMember 2018-04-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember us-gaap:NaturalGasGatheringTransportationMarketingAndProcessingMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:GasSalesMember 2018-04-01 2018-06-30 0000007332 srt:GuarantorSubsidiariesMember swn:GasSalesMember 2018-04-01 2018-06-30 0000007332 srt:ParentCompanyMember swn:GasGatheringMember 2018-04-01 2018-06-30 0000007332 srt:ConsolidationEliminationsMember swn:OilSalesMember 2018-04-01 2018-06-30 0000007332 srt:NonGuarantorSubsidiariesMember swn:NaturalGasLiquidsSalesMember 2018-04-01 2018-06-30 xbrli:pure utreg:MBbls iso4217:USD utreg:bbl xbrli:shares swn:derivative_position iso4217:USD swn:segment iso4217:USD utreg:MMBTU utreg:Bcf iso4217:USD xbrli:shares swn:lawsuit

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-Q

(Mark One)

☒ Quarterly Report pursuant to Section 13 or 15(d) of the Securities

Exchange Act of 1934

For the quarterly period ended June 30, 2019

Or

☐ Transition Report pursuant to Section 13 or 15(d) of the Securities

Exchange Act of 1934

For the transition period from ________ to ________

Commission file number: 001-08246

(Former name, former address and former fiscal year, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, Par Value $0.01		SWN		New York Stock Exchange

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company.  See the definitions of “large accelerated filer”, “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date:

SOUTHWESTERN ENERGY COMPANY

INDEX TO FORM 10-Q

FOR THE QUARTERLY PERIOD ENDED JUNE 30, 2019

CAUTIONARY STATEMENT ABOUT FORWARD-LOOKING STATEMENTS

All statements, other than historical fact or present financial information, may be deemed to be forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).  All statements that address activities, outcomes and other matters that should or may occur in the future, including, without limitation, statements regarding the financial position, business strategy, production and reserve growth and other plans and objectives for our future operations, are forward-looking statements.  Although we believe the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance.  We have no obligation and make no undertaking to publicly update or revise any forward-looking statements, except as may be required by law.

Forward-looking statements include the items identified in the preceding paragraph, information concerning possible or assumed future results of operations and other statements in this Quarterly Report on Form 10-Q identified by words such as “anticipate,” “intend,” “plan,” “project,” “estimate,” “continue,” “potential,” “should,” “could,” “may,” “will,” “objective,” “guidance,” “outlook,” “effort,” “expect,” “believe,” “predict,” “budget,” “projection,” “goal,” “forecast,” “target” or similar words.

You should not place undue reliance on forward-looking statements.  They are subject to known and unknown risks, uncertainties and other factors that may affect our operations, markets, products, services and prices and cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.  In addition to any assumptions and other factors referred to specifically in connection with forward-looking statements, risks, uncertainties and factors that could cause our actual results to differ materially from those indicated in any forward-looking statement include, but are not limited to:

Should one or more of the risks or uncertainties described above or elsewhere in this Quarterly Report occur, or should underlying assumptions prove incorrect, our actual results and plans could differ materially from those expressed in any forward-looking statements.  We specifically disclaim all responsibility to update publicly any information contained in a forward-looking statement or any forward-looking statement in its entirety and therefore disclaim any resulting liability for potentially related damages.

All forward-looking statements attributable to us are expressly qualified in their entirety by this cautionary statement.