1.0.0.3 false Statement Of Cash Flows Indirect (USD $) In Millions false 1 $ false false Shares Standard http://www.xbrl.org/2003/instance shares 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDperShareItemType Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 false 2 $ false false Shares Standard http://www.xbrl.org/2003/instance shares 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDperShareItemType Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares 0 5 CASH FLOWS FROM 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 duk_ProfitLoss duk false credit duration monetary No definition available. false false false false false false false false false 1 true true 631000000 631 false false 2 true true 815000000 815 false false No definition available. No authoritative reference available. false 7 Adjustments to reconcile net income to net cash provided by operating activities 4 us-gaap_AdjustmentsToReconcileIncomeLossToNetCashProvidedByUsedInContinuingOperationsAbstract 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 and amortization (including amortization of nuclear fuel) 5 duk_AdjustmentDepreciationAndAmortization duk false debit duration monetary No definition available. false false false false false false false false false 1 false true 917000000 917 false false 2 false true 908000000 908 false false No definition available. No authoritative reference available. false 9 Gains on sales of other assets 5 us-gaap_GainLossOnSaleOfOtherAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -19000000 -19 false false 2 false true -75000000 -75 false false No definition available. No authoritative reference available. false 10 Impairments and other charges 5 us-gaap_AssetImpairmentCharges us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 12000000 12 false false 2 false true 0 0 false false No definition available. No authoritative reference available. false 11 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 716000000 716 false false 2 false true 286000000 286 false false No definition available. No authoritative reference available. false 12 Equity in (earnings) loss of 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 -25000000 -25 false false 2 false true 18000000 18 false false No definition available. No authoritative reference available. false 13 Contributions to qualified pension plans 5 us-gaap_PensionAndOtherPostretirementBenefitContributions us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -500000000 -500 false false 2 false true 0 0 false false No definition available. No authoritative reference available. false 14 (Increase) decrease in 5 us-gaap_IncreaseDecreaseInOperatingAssetsAbstract 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 15 Net realized and unrealized mark-to-market and hedging transactions 6 duk_RealizedUnrealizedGainLossOnDerivativesAndCommodityContracts duk false credit duration monetary No definition available. false false false false false false false false false 1 false true -18000000 -18 false false 2 false true -103000000 -103 false false No definition available. No authoritative reference available. false 16 Receivables 6 us-gaap_IncreaseDecreaseInReceivables us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 200000000 200 false false 2 false true -79000000 -79 false false No definition available. No authoritative reference available. false 17 Inventory 6 us-gaap_IncreaseDecreaseInInventories us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -227000000 -227 false false 2 false true -9000000 -9 false false No definition available. No authoritative reference available. false 18 Other current assets 6 duk_IncreaseDecreaseOtherCurrentAssets duk false credit duration monetary No definition available. false false false false false false false false false 1 false true -338000000 -338 false false 2 false true 24000000 24 false false No definition available. No authoritative reference available. false 19 Increase (decrease) in 5 us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract 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 Accounts payable 6 us-gaap_IncreaseDecreaseInAccountsPayable us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -300000000 -300 false false 2 false true -54000000 -54 false false No definition available. No authoritative reference available. false 21 Taxes accrued 6 us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 49000000 49 false false 2 false true 26000000 26 false false No definition available. No authoritative reference available. false 22 Other current liabilities 6 duk_IncreaseDecreaseOtherCurrentLiabilities duk false debit duration monetary No definition available. false false false false false false false false false 1 false true -130000000 -130 false false 2 false true -118000000 -118 false false No definition available. No authoritative reference available. false 23 Other assets 5 us-gaap_IncreaseDecreaseInOtherOperatingAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -1000000 -1 false false 2 false true 72000000 72 false false No definition available. No authoritative reference available. false 24 Other liabilities 5 us-gaap_IncreaseDecreaseInOtherOperatingLiabilities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 50000000 50 false false 2 false true -16000000 -16 false false No definition available. No authoritative reference available. false 25 Net cash provided by 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 1017000000 1017 false false 2 false true 1695000000 1695 false false No definition available. No authoritative reference available. true 26 CASH FLOWS FROM 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 27 Capital expenditures 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 -1900000000 -1900 false false 2 false true -2142000000 -2142 false false No definition available. No authoritative reference available. false 28 Investment expenditures 4 us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -66000000 -66 false false 2 false true -10000000 -10 false false No definition available. No authoritative reference available. false 29 Acquisitions, net of cash acquired 4 us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -114000000 -114 false false 2 false true 0 0 false false No definition available. No authoritative reference available. false 30 Purchases of available-for-sale securities 4 us-gaap_PaymentsToAcquireAvailableForSaleSecurities us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -1845000000 -1845 false false 2 false true -32238000000 -32238 false false No definition available. No authoritative reference available. false 31 Proceeds from sales and maturities of available-for-sale securities 4 us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 1826000000 1826 false false 2 false true 31723000000 31723 false false No definition available. No authoritative reference available. false 32 Net proceeds from the sales of other assets and sales of and collections on notes receivable 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 44000000 44 false false 2 false true 78000000 78 false false No definition available. No authoritative reference available. false 33 Purchases of emission allowances 4 duk_PurchasesOfEmissionAllowances duk false credit duration monetary No definition available. false false false false false false false false false 1 false true -38000000 -38 false false 2 false true -23000000 -23 false false No definition available. No authoritative reference available. false 34 Sales of emission allowances 4 duk_SaleOfEmissionAllowances duk false debit duration monetary No definition available. false false false false false false false false false 1 false true 27000000 27 false false 2 false true 80000000 80 false false No definition available. No authoritative reference available. false 35 Change in restricted cash 4 us-gaap_IncreaseDecreaseInRestrictedCash us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -40000000 -40 false false 2 false true 17000000 17 false false No definition available. No authoritative reference available. false 36 Other 4 us-gaap_PaymentsForProceedsFromOtherInvestingActivities us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -27000000 -27 false false 2 false true -12000000 -12 false false No definition available. No authoritative reference available. false 37 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 -2133000000 -2133 false false 2 false true -2527000000 -2527 false false No definition available. No authoritative reference available. true 39 Proceeds from the: 4 us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNetAbstract 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 40 Issuance of long-term debt 5 us-gaap_ProceedsFromIssuanceOfLongTermDebt us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 2064000000 2064 false false 2 false true 2393000000 2393 false false No definition available. No authoritative reference available. false 41 Issuance of common stock related to employee benefit plans 5 us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 286000000 286 false false 2 false true 23000000 23 false false No definition available. No authoritative reference available. false 42 Payments for the redemption of long-term debt 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 -729000000 -729 false false 2 false true -803000000 -803 false false No definition available. No authoritative reference available. false 43 Notes payable and commercial paper 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 -148000000 -148 false false 2 false true -187000000 -187 false false No definition available. No authoritative reference available. false 44 Distributions to noncontrolling interests 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 -33000000 -33 false false 2 false true -1000000 -1 false false No definition available. No authoritative reference available. false 45 Contributions from noncontrolling interests 4 us-gaap_ProceedsFromMinorityShareholders 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 3000000 3 false false No definition available. No authoritative reference available. false 46 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 -596000000 -596 false false 2 false true -549000000 -549 false false No definition available. No authoritative reference available. false 47 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 -8000000 -8 false false 2 false true -8000000 -8 false false No definition available. No authoritative reference available. false 48 Net cash provided by 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 836000000 836 false false 2 false true 871000000 871 false false No definition available. No authoritative reference available. true 49 Net (decrease) increase 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 -280000000 -280 false false 2 false true 39000000 39 false false No definition available. No authoritative reference available. true 50 Cash and cash equivalents at beginning of period 3 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false true false false 1 false true 986000000 986 false false 2 false true 678000000 678 false false No definition available. No authoritative reference available. false 51 Cash and cash equivalents at end of period 3 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false true false 1 false true 706000000 706 false false 2 false true 717000000 717 false false No definition available. No authoritative reference available. false 53 Significant non-cash transactions: 4 us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract 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 54 Accrued capital expenditures 5 us-gaap_CapitalExpendituresIncurredButNotYetPaid us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 241000000 241 false false 2 false true 125000000 125 false false No definition available. No authoritative reference available. false 55 Dividends declared but not paid 5 duk_DividendsDeclaredAndNotPaid duk false credit duration monetary No definition available. false false false false false false false false false 1 true true 310000000 310 false false 2 true true 291000000 291 false false No definition available. No authoritative reference available. false false 2 49 false Millions UnKnown UnKnown false true