1.0.0.3 true Statement Of Shareholders Equity And Other Comprehensive Income (USD $) In Millions false 1 $ true false false false Common Stock Shares us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi duk_CommonStockSharesMember us-gaap_StatementEquityComponentsAxis explicitMember Shares Standard http://www.xbrl.org/2003/instance shares 0 false 2 $ true false false false Common Stock us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_CommonStockMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 3 $ true false false false Additional Paid-in Capital [Member] us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AdditionalPaidInCapitalMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 4 $ true false false false Retained Earnings us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_RetainedEarningsMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 5 $ true false false false Foreign Currency Adjustments us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AccumulatedTranslationAdjustmentMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 6 $ true false false false Net Gains (Losses) on Cash Flow Hedges us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 7 $ true false false false Other us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi duk_AccumulatedOtherChangesMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 8 $ true false false false Pension and OPEB Related Adjustments to AOCI us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 9 $ true false false false Common Stockholders' Equity us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi duk_ParentMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 10 $ true false false false Noncontrolling Interests us-gaap_StatementEquityComponentsAxis xbrldi http://xbrl.org/2006/xbrldi duk_NoncontrollingInterestMember us-gaap_StatementEquityComponentsAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 false 11 $ 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 6 Beginning Balance at Dec. 31, 2007 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false true false false 1 false false 0 0 true false 2 true true 1000000 1 true false 3 true true 19933000000 19933 true false 4 true true 1398000000 1398 true false 5 true true -7000000 -7 true false 6 true true -54000000 -54 true false 7 true true 2000000 2 true false 8 true true -74000000 -74 true false 9 true true 21199000000 21199 true false 10 true true 180000000 180 true false 11 true true 21379000000 21379 false false No definition available. No authoritative reference available. false 5 Beginning Balance at Dec. 31, 2007 3 duk_SharesOutstanding duk false na instant shares No definition available. false false false true false false true false false 1 false true 1262000000 1262 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. No authoritative reference available. false 7 Net income 3 duk_ProfitLoss duk false credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true 816000000 816 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 816000000 816 true false 10 false true -1000000 -1 true false 11 false true 815000000 815 false false No definition available. No authoritative reference available. false 8 Other Comprehensive Income 3 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. false 9 Foreign currency translation adjustments 4 us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 123000000 123 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 123000000 123 true false 10 false true 7000000 7 true false 11 false true 130000000 130 false false No definition available. No authoritative reference available. false 10 Net unrealized gain on cash flow hedges 4 us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false true -12000000 -12 [5] true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true -12000000 -12 [5] true false 10 false false 0 0 true false 11 false true -12000000 -12 [5] false false No definition available. No authoritative reference available. false 11 Reclassification into earnings from cash flow hedges 4 us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false true 5000000 5 [6] true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 5000000 5 [6] true false 10 false false 0 0 true false 11 false true 5000000 5 [6] false false No definition available. No authoritative reference available. false 12 SFAS No. 158 amortization 4 us-gaap_ApplicationOfRecognitionProvisionsOfSFAS158EffectOnAccumulatedOtherComprehensiveIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false true 12000000 12 [3] true false 9 false true 12000000 12 [3] true false 10 false false 0 0 true false 11 false true 12000000 12 [3] false false No definition available. No authoritative reference available. false 13 Unrealized loss on investments in auction rate securities 4 duk_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnInvestmentsInAuctionRateDebtSecuritiesArisingDuringThePeriodNetofTax duk false credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false true -16000000 -16 [2] true false 8 false false 0 0 true false 9 false true -16000000 -16 [2] true false 10 false false 0 0 true false 11 false true -16000000 -16 [2] false false No definition available. No authoritative reference available. false 14 Reclassification of losses on investments in auction rate securities and other available for sale securities into earnings 4 us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false true 2000000 2 [1] true false 8 false false 0 0 true false 9 false true 2000000 2 [1] true false 10 false false 0 0 true false 11 false true 2000000 2 [1] false false No definition available. No authoritative reference available. false 15 Other 4 duk_OtherComprehensiveIncomeOtherNetOfTax duk false debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false true -8000000 -8 [4] true false 8 false false 0 0 true false 9 false true -8000000 -8 [4] true false 10 false false 0 0 true false 11 false true -8000000 -8 [4] false false No definition available. No authoritative reference available. false 16 Total comprehensive income 4 duk_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest duk false credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 922000000 922 true false 10 false true 6000000 6 true false 11 false true 928000000 928 false false No definition available. No authoritative reference available. false 17 Common stock issuances, including dividend reinvestment and employee benefits 3 us-gaap_StockIssuedDuringPeriodSharesNewIssues us-gaap true na duration shares No definition available. false false false false false false false false false 1 false true 3000000 3 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. No authoritative reference available. false 18 Common stock issuances, including dividend reinvestment and employee benefits 3 us-gaap_StockIssuedDuringPeriodValueNewIssues us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true 41000000 41 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 41000000 41 true false 10 false false 0 0 true false 11 false true 41000000 41 false false No definition available. No authoritative reference available. false 20 Common stock dividends 3 us-gaap_CashDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true -850000000 -850 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true -850000000 -850 true false 10 false false 0 0 true false 11 false true -850000000 -850 false false No definition available. No authoritative reference available. false 21 Additional amounts related to the spin-off of Spectra Energy 3 duk_SpinOffOfBusiness duk false credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true -11000000 -11 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true -11000000 -11 true false 10 false true 3000000 3 true false 11 false true -8000000 -8 false false No definition available. No authoritative reference available. false 22 Ending Balance at Jun. 30, 2008 3 duk_SharesOutstanding duk false na instant shares No definition available. false false false true false false false true false 1 false true 1265000000 1265 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. No authoritative reference available. false 23 Ending Balance at Jun. 30, 2008 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false false true false 1 false false 0 0 true false 2 false true 1000000 1 true false 3 false true 19974000000 19974 true false 4 false true 1353000000 1353 true false 5 false true 116000000 116 true false 6 false true -61000000 -61 true false 7 false true -20000000 -20 true false 8 false true -62000000 -62 true false 9 false true 21301000000 21301 true false 10 false true 189000000 189 true false 11 false true 21490000000 21490 false false No definition available. No authoritative reference available. false 6 Beginning Balance at Mar. 31, 2008 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false true false false 1 false false 0 0 false false 2 false true 1000000 1 true false 3 false false 0 0 false false 4 false false 0 0 false false 5 false false 0 0 false false 6 false false 0 0 false false 7 false false 0 0 false false 8 false false 0 0 false false 9 false false 0 0 false false 10 false false 0 0 false false 11 false false 0 0 false false No definition available. No authoritative reference available. false 8 Other Comprehensive Income 3 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract 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 true false 3 false false 0 0 false false 4 false false 0 0 false false 5 false false 0 0 false false 6 false false 0 0 false false 7 false false 0 0 false false 8 false false 0 0 false false 9 false false 0 0 false false 10 false false 0 0 false false 11 false false 0 0 false false No definition available. false 23 Ending Balance at Jun. 30, 2008 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false false true false 1 false false 0 0 false false 2 false true 1000000 1 true false 3 false false 0 0 false false 4 false false 0 0 false false 5 false false 0 0 false false 6 false false 0 0 false false 7 false false 0 0 false false 8 false false 0 0 false false 9 false false 0 0 false false 10 false false 0 0 false false 11 false false 0 0 false false No definition available. No authoritative reference available. false 6 Beginning Balance at Dec. 31, 2008 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false true false false 1 false false 0 0 true false 2 false true 1000000 1 true false 3 false true 20106000000 20106 true false 4 false true 1607000000 1607 true false 5 false true -306000000 -306 true false 6 false true -41000000 -41 true false 7 false true -28000000 -28 true false 8 false true -351000000 -351 true false 9 false true 20988000000 20988 true false 10 false true 163000000 163 true false 11 false true 21151000000 21151 false false No definition available. No authoritative reference available. false 5 Beginning Balance at Dec. 31, 2008 3 duk_SharesOutstanding duk false na instant shares No definition available. false false false true false false true false false 1 false true 1272000000 1272 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. No authoritative reference available. false 7 Net income 3 duk_ProfitLoss duk false credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true 620000000 620 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 620000000 620 true false 10 false true 11000000 11 true false 11 false true 631000000 631 false false No definition available. No authoritative reference available. false 8 Other Comprehensive Income 3 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. false 9 Foreign currency translation adjustments 4 us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false true 177000000 177 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 177000000 177 true false 10 false true 9000000 9 true false 11 false true 186000000 186 false false No definition available. No authoritative reference available. false 10 Net unrealized gain on cash flow hedges 4 us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false true 1000000 1 [5] true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 1000000 1 [5] true false 10 false false 0 0 true false 11 false true 1000000 1 [5] false false No definition available. No authoritative reference available. false 11 Reclassification into earnings from cash flow hedges 4 us-gaap_OtherComprehensiveIncomeReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false true 14000000 14 [6] true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 14000000 14 [6] true false 10 false false 0 0 true false 11 false true 14000000 14 [6] false false No definition available. No authoritative reference available. false 12 SFAS No. 158 amortization 4 us-gaap_ApplicationOfRecognitionProvisionsOfSFAS158EffectOnAccumulatedOtherComprehensiveIncomeNetOfTax us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false true 18000000 18 [3] true false 9 false true 18000000 18 [3] true false 10 false false 0 0 true false 11 false true 18000000 18 [3] false false No definition available. No authoritative reference available. false 13 Unrealized loss on investments in auction rate securities 4 duk_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnInvestmentsInAuctionRateDebtSecuritiesArisingDuringThePeriodNetofTax duk false credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false true -6000000 -6 [2] true false 8 false false 0 0 true false 9 false true -6000000 -6 [2] true false 10 false false 0 0 true false 11 false true -6000000 -6 [2] false false No definition available. No authoritative reference available. false 15 Other 4 duk_OtherComprehensiveIncomeOtherNetOfTax duk false debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false true 1000000 1 [4] true false 8 false false 0 0 true false 9 false true 1000000 1 [4] true false 10 false false 0 0 true false 11 false true 1000000 1 [4] false false No definition available. No authoritative reference available. false 16 Total comprehensive income 4 duk_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest duk false credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 825000000 825 true false 10 false true 20000000 20 true false 11 false true 845000000 845 false false No definition available. No authoritative reference available. false 17 Common stock issuances, including dividend reinvestment and employee benefits 3 us-gaap_StockIssuedDuringPeriodSharesNewIssues us-gaap true na duration shares No definition available. false false false false false false false false false 1 false true 22000000 22 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. No authoritative reference available. false 18 Common stock issuances, including dividend reinvestment and employee benefits 3 us-gaap_StockIssuedDuringPeriodValueNewIssues us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true 305000000 305 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 305000000 305 true false 10 false false 0 0 true false 11 false true 305000000 305 false false No definition available. No authoritative reference available. false 19 Purchases and other changes in noncontrolling interest in subsidiaries 3 us-gaap_MinorityInterestDecreaseFromRedemptions us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false true 14000000 14 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true 14000000 14 true false 10 false true -49000000 -49 true false 11 false true -35000000 -35 false false No definition available. No authoritative reference available. false 20 Common stock dividends 3 us-gaap_CashDividends us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false false 0 0 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false true -906000000 -906 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false true -906000000 -906 true false 10 false false 0 0 true false 11 false true -906000000 -906 false false No definition available. No authoritative reference available. false 22 Ending Balance at Jun. 30, 2009 3 duk_SharesOutstanding duk false na instant shares No definition available. false false false true false false false true false 1 false true 1294000000 1294 true false 2 false false 0 0 true false 3 false false 0 0 true false 4 false false 0 0 true false 5 false false 0 0 true false 6 false false 0 0 true false 7 false false 0 0 true false 8 false false 0 0 true false 9 false false 0 0 true false 10 false false 0 0 true false 11 false false 0 0 false false No definition available. No authoritative reference available. false 23 Ending Balance at Jun. 30, 2009 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false false true false 1 false false 0 0 true false 2 false true 1000000 1 true false 3 false true 20425000000 20425 true false 4 false true 1321000000 1321 true false 5 false true -129000000 -129 true false 6 false true -26000000 -26 true false 7 false true -33000000 -33 true false 8 false true -333000000 -333 true false 9 false true 21226000000 21226 true false 10 false true 134000000 134 true false 11 false true 21360000000 21360 false false No definition available. No authoritative reference available. false 6 Beginning Balance at Mar. 31, 2009 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false true false false 1 false false 0 0 false false 2 false true 1000000 1 true false 3 false false 0 0 false false 4 false false 0 0 false false 5 false false 0 0 false false 6 false false 0 0 false false 7 false false 0 0 false false 8 false false 0 0 false false 9 false false 0 0 false false 10 false false 0 0 false false 11 false false 0 0 false false No definition available. No authoritative reference available. false 8 Other Comprehensive Income 3 us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract 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 true false 3 false false 0 0 false false 4 false false 0 0 false false 5 false false 0 0 false false 6 false false 0 0 false false 7 false false 0 0 false false 8 false false 0 0 false false 9 false false 0 0 false false 10 false false 0 0 false false 11 false false 0 0 false false No definition available. false 23 Ending Balance at Jun. 30, 2009 3 duk_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest duk false credit instant monetary No definition available. false false false true false false false true false 1 false false 0 0 false false 2 true true 1000000 1 true false 3 false false 0 0 false false 4 false false 0 0 false false 5 false false 0 0 false false 6 false false 0 0 false false 7 false false 0 0 false false 8 false false 0 0 false false 9 false false 0 0 false false 10 false false 0 0 false false 11 false false 0 0 false false No definition available. No authoritative reference available. false 1 Net of $2 tax expense in 2008. 2 Net of $3 tax benefit in 2009 and $11 tax benefit in 2008. 3 Net of $9 tax expense in 2009 and $7 tax expense in 2008. 4 Net of insignificant tax expense in 2009 and $6 tax benefit in 2008. 5 Net unrealized gains (losses) on cash flow hedges, net of insignificant tax expense in 2009 and $5 tax benefit in 2008. 6 Reclassification into earnings from cash flow hedges, net of $8 tax expense in 2009 and $2 tax expense in 2008. false 11 41 false Millions Millions UnKnown false true