1.0.0.3 false CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Millions false 3 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 4 $ false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u002 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 5 OPERATING ACTIVITIES 3 us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 6 Net income 4 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 245000000 245.0 false false 2 true true 569500000 569.5 false false No definition available. No authoritative reference available. false 7 Adjustments to reconcile net income to net cash provided from operating activities 4 us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 8 Depreciation, depletion and amortization 5 us-gaap_DepreciationDepletionAndAmortization us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 516100000 516.1 false false 2 false true 357600000 357.6 false false No definition available. No authoritative reference available. false 9 Deferred income taxes 5 us-gaap_DeferredIncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 115800000 115.8 false false 2 false true 297300000 297.3 false false No definition available. No authoritative reference available. false 10 Abandonment and impairment 5 us-gaap_ExplorationAbandonmentAndImpairmentExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 12600000 12.6 false false 2 false true 20900000 20.9 false false No definition available. No authoritative reference available. false 11 Share-based compensation 5 us-gaap_ShareBasedCompensation us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 17400000 17.4 false false 2 false true 12600000 12.6 false false No definition available. No authoritative reference available. false 12 Dry exploratory well expense 5 us-gaap_ResultsOfOperationsDryHoleCosts us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 3600000 3.6 false false 2 false true 2300000 2.3 false false No definition available. No authoritative reference available. false 13 Net (gain) from asset sales 5 us-gaap_GainLossOnSaleOfPropertyPlantEquipment us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -1400000 -1.4 false false 2 false true -62400000 -62.4 false false No definition available. No authoritative reference available. false 14 (Income) from unconsolidated affiliates 5 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -4800000 -4.8 false false 2 false true -1300000 -1.3 false false No definition available. No authoritative reference available. false 15 Distributions from unconsolidated affiliates and other 5 us-gaap_EquityMethodInvestmentDividendsOrDistributions us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 2000000 2.0 false false 2 false true 1300000 1.3 false false No definition available. No authoritative reference available. false 16 Net mark-to-market (gain) loss on basis-only swaps 5 us-gaap_UnrealizedGainLossOnDerivatives us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 173400000 173.4 false false 2 false true -7500000 -7.5 false false No definition available. No authoritative reference available. false 17 Changes in operating assets and liabilities 5 us-gaap_IncreaseDecreaseInOperatingCapital us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 117800000 117.8 false false 2 false true -77300000 -77.3 false false No definition available. No authoritative reference available. false 18 NET CASH PROVIDED FROM OPERATING ACTIVITIES 4 us-gaap_NetCashProvidedByUsedInOperatingActivities us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 1197500000 1197.5 false false 2 false true 1113000000 1113.0 false false No definition available. No authoritative reference available. true 19 INVESTING ACTIVITIES 3 us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 20 Property, plant and equipment, including dry exploratory well expense 4 us-gaap_PaymentsToAcquirePropertyPlantAndEquipment us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -1017300000 -1017.3 false false 2 false true -1896500000 -1896.5 false false No definition available. No authoritative reference available. false 21 Other investments 4 us-gaap_PaymentsToAcquireOtherProductiveAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true -21500000 -21.5 false false No definition available. No authoritative reference available. false 22 Total capital expenditures 4 us-gaap_PaymentsToAcquireProductiveAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -1017300000 -1017.3 false false 2 false true -1918000000 -1918.0 false false No definition available. No authoritative reference available. true 23 Cash used in disposition of assets 4 us-gaap_PaymentsForProceedsFromRemovalCosts us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -1200000 -1.2 false false 2 false true -3300000 -3.3 false false No definition available. No authoritative reference available. false 24 Proceeds from disposition of assets 4 us-gaap_ProceedsFromSaleOfProductiveAssets us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 16200000 16.2 false false 2 false true 127500000 127.5 false false No definition available. No authoritative reference available. false 25 NET CASH USED IN INVESTING ACTIVITIES 4 us-gaap_NetCashProvidedByUsedInInvestingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -1002300000 -1002.3 false false 2 false true -1793800000 -1793.8 false false No definition available. No authoritative reference available. true 26 FINANCING ACTIVITIES 3 us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 27 Common stock issued 4 us-gaap_ProceedsFromIssuanceOfCommonStock us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 11300000 11.3 false false 2 false true 5000000 5.0 false false No definition available. No authoritative reference available. false 28 Common stock repurchased 4 us-gaap_PaymentsForRepurchaseOfCommonStock us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -6100000 -6.1 false false 2 false true -14500000 -14.5 false false No definition available. No authoritative reference available. false 29 Long-term debt issued, net of issuance costs 4 us-gaap_ProceedsFromIssuanceOfLongTermDebt us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 397800000 397.8 false false 2 false true 1616600000 1616.6 false false No definition available. No authoritative reference available. false 30 Long-term debt repaid 4 us-gaap_RepaymentsOfLongTermDebt us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -375000000 -375.0 false false 2 false true -693000000 -693.0 false false No definition available. No authoritative reference available. false 31 Change in short-term debt 4 us-gaap_ProceedsFromRepaymentsOfShortTermDebt us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -192600000 -192.6 false false 2 false true -205600000 -205.6 false false No definition available. No authoritative reference available. false 32 Checks outstanding in excess of cash balances 4 us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 14100000 14.1 false false 2 false true 14200000 14.2 false false No definition available. No authoritative reference available. false 33 Dividends paid 4 us-gaap_PaymentsOfDividends us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -65300000 -65.3 false false 2 false true -63700000 -63.7 false false No definition available. No authoritative reference available. false 34 Excess tax benefits from share-based compensation 4 us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 1300000 1.3 false false 2 false true 12900000 12.9 false false No definition available. No authoritative reference available. false 35 Distribution to noncontrolling interest 4 us-gaap_PaymentsOfDividendsMinorityInterest us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -4600000 -4.6 false false 2 false true -6300000 -6.3 false false No definition available. No authoritative reference available. false 36 Other 4 us-gaap_ProceedsFromPaymentsForOtherFinancingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 1000000 1.0 false false No definition available. No authoritative reference available. false 37 NET CASH (USED IN) PROVIDED FROM FINANCING ACTIVITIES 4 us-gaap_NetCashProvidedByUsedInFinancingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -219100000 -219.1 false false 2 false true 666600000 666.6 false false No definition available. No authoritative reference available. true 38 Change in cash and cash equivalents 3 us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true -23900000 -23.9 false false 2 false true -14200000 -14.2 false false No definition available. No authoritative reference available. true 39 Beginning cash and cash equivalents 3 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false true false false 1 true true 23900000 23.9 false false 2 true true 14200000 14.2 false false No definition available. No authoritative reference available. false false 2 35 false HundredThousands UnKnown UnKnown false true