2.4.0.8041101 - Disclosure - Variable Interest Entities (Narrative) (Details)truefalseIn Millions, unless otherwise specifiedfalse1false falsefalseFROM_Jan01_2013_TO_Jun30_2013http://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:002false USDtruefalse$AS_OF_Dec31_2010_duk_VariableInterestEntityByTypeAxis_DukenetAndAlindaCapitalPartnersLlcOwnershipInNewJointVentureMemberhttp://www.sec.gov/CIK0001326160instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseDukeNet And Alinda Capital Partners LLC Ownership In The New Joint Venture [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukenetAndAlindaCapitalPartnersLlcOwnershipInNewJointVentureMemberduk_VariableInterestEntityByTypeAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDtruefalseFROM_Jan01_2013_TO_Jun30_2013_duk_VariableInterestEntityByTypeAxis_CinergyReceivablesMemberhttp://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseCinergy Receivables [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_CinergyReceivablesMemberduk_VariableInterestEntityByTypeAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$4false truefalseFROM_Jan01_2013_TO_Jun30_2013_duk_VariableInterestEntityByTypeAxis_CinergyReceivablesMember_us-gaap_RangeAxis_MinimumMemberhttp://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseCinergy Receivables [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_CinergyReceivablesMemberduk_VariableInterestEntityByTypeAxisexplicitMemberfalsefalseMinimum [Member]us-gaap_RangeAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_MinimumMemberus-gaap_RangeAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli05false truefalseFROM_Jan01_2013_TO_Jun30_2013_duk_VariableInterestEntityByTypeAxis_CinergyReceivablesMember_us-gaap_RangeAxis_MaximumMemberhttp://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseCinergy Receivables [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_CinergyReceivablesMemberduk_VariableInterestEntityByTypeAxisexplicitMemberfalsefalseMaximum [Member]us-gaap_RangeAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_MaximumMemberus-gaap_RangeAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli06false truefalseFROM_Jan01_2013_TO_Jun30_2013_duk_VariableInterestEntityByTypeAxis_OtherViesMember_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_VariableInterestEntityNotPrimaryBeneficiaryMemberhttp://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseOther VIEs [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_OtherViesMemberduk_VariableInterestEntityByTypeAxisexplicitMemberfalsefalseVariable Interest Entity, Not Primary Beneficiary [Member]us-gaap_VariableInterestEntitiesByClassificationOfEntityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_VariableInterestEntityNotPrimaryBeneficiaryMemberus-gaap_VariableInterestEntitiesByClassificationOfEntityAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli07false USDtruefalseFROM_Jan01_2013_TO_Jun30_2013_dei_LegalEntityAxis_DukeEnergyCarolinasMember_duk_VariableInterestEntityByTypeAxis_DerfMember_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_VariableInterestEntityPrimaryBeneficiaryMemberhttp://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseDuke Energy Carolinas [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyCarolinasMemberdei_LegalEntityAxisexplicitMemberfalsefalseDERF [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DerfMemberduk_VariableInterestEntityByTypeAxisexplicitMemberfalsefalseVariable Interest Entity, Primary Beneficiary [Member]us-gaap_VariableInterestEntitiesByClassificationOfEntityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_VariableInterestEntityPrimaryBeneficiaryMemberus-gaap_VariableInterestEntitiesByClassificationOfEntityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$8false USDtruefalse$AS_OF_Dec31_2012_dei_LegalEntityAxis_ProgressEnergyMember_duk_VariableInterestEntityByTypeAxis_FpcCapitalITrustMemberhttp://www.sec.gov/CIK0001326160instant2012-12-31T00:00:000001-01-01T00:00:00falsefalseProgress Energy [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_ProgressEnergyMemberdei_LegalEntityAxisexplicitMemberfalsefalseFPC Capital I Trust [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_FpcCapitalITrustMemberduk_VariableInterestEntityByTypeAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$9false truefalseFROM_Jan01_2013_TO_Jun30_2013_dei_LegalEntityAxis_DukeEnergyOhioMember_duk_VariableInterestEntityByTypeAxis_CinergyReceivablesMemberhttp://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseDuke Energy Ohio [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyOhioMemberdei_LegalEntityAxisexplicitMemberfalsefalseCinergy Receivables [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_CinergyReceivablesMemberduk_VariableInterestEntityByTypeAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli010false truefalseAS_OF_Jan12_2012_dei_LegalEntityAxis_DukeEnergyIndianaMemberhttp://www.sec.gov/CIK0001326160instant2012-01-12T00:00:000001-01-01T00:00:00falsefalseDuke Energy Indiana [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyIndianaMemberdei_LegalEntityAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli011false truefalseFROM_Jan01_2013_TO_Jun30_2013_dei_LegalEntityAxis_DukeEnergyIndianaMember_duk_VariableInterestEntityByTypeAxis_CinergyReceivablesMemberhttp://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseDuke Energy Indiana [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyIndianaMemberdei_LegalEntityAxisexplicitMemberfalsefalseCinergy Receivables [Member]duk_VariableInterestEntityByTypeAxisxbrldihttp://xbrl.org/2006/xbrldiduk_CinergyReceivablesMemberduk_VariableInterestEntityByTypeAxisexplicitMemberPureStandardhttp://www.xbrl.org/2003/instancepurexbrli01true 3us-gaap_VariableInterestEntityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Variable Interest Entity [Line Items]2false 4duk_ProceedsReceivedForSaleOfReceivablesPortionReceivedAsNotePayableduk_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsetruefalse00falsefalsefalse2falsetruefalse00falsefalsefalse3truetruefalse0.250.25falsefalsefalse4falsetruefalse00falsefalsefalse5falsetruefalse00falsefalsefalse6falsetruefalse00falsefalsefalse7falsetruefalse00falsefalsefalse8falsetruefalse00falsefalsefalse9falsetruefalse00falsefalsefalse10falsetruefalse00falsefalsefalse11falsetruefalse00falsefalsefalsenum:percentItemTypepureProceeds Received For Sale Of Receivables Portion Received As Note PayableNo definition available.false0Proceeds received for sale of receivables, portion received as note payable3false 4duk_BorrowingLimitationduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsetruefalse00falsefalsefalse2falsetruefalse00falsefalsefalse3truetruefalse0.750.75falsefalsefalse4falsetruefalse00falsefalsefalse5falsetruefalse00falsefalsefalse6falsetruefalse00falsefalsefalse7falsetruefalse00falsefalsefalse8falsetruefalse00falsefalsefalse9falsetruefalse00falsefalsefalse10falsetruefalse00falsefalsefalse11falsetruefalse00falsefalsefalsenum:percentItemTypepureBorrowing limitation for transferred receivables.No definition available.false0Borrowing limitation for CRC4false 4duk_ReceivablesToMaintainMinimumEquityBalanceduk_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse30000003USD$falsetruefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryMinimum equity Balance required by Cinergy ReceivablesNo definition available.false2Minimum Equity Balance required by Cinergy Receivables5false 4duk_SubordinatedRetainedInterestLimitationOfTotalProceedsduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsetruefalse00falsefalsefalse2falsetruefalse00falsefalsefalse3falsetruefalse00falsefalsefalse4truetruefalse0.10.1falsefalsefalse5truetruefalse0.20.2falsefalsefalse6falsetruefalse00falsefalsefalse7falsetruefalse00falsefalsefalse8falsetruefalse00falsefalsefalse9falsetruefalse00falsefalsefalse10falsetruefalse00falsefalsefalse11falsetruefalse00falsefalsefalsenum:percentItemTypepureSubordinated Retained Interest Limitation Of The Total ProceedsNo definition available.false0Subordinated retained interest limitation of the total proceeds6false 4duk_SecuredCreditFacilityOfVieduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7truefalsefalse300000000300falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetarySecured Credit Facility Of VieNo definition available.false2Secured credit facility of variable interest entities7false 4duk_SaleOfReceivablesFixedRateUsedInCalculationduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsetruefalse00falsefalsefalse2falsetruefalse00falsefalsefalse3falsetruefalse00falsefalsefalse4falsetruefalse00falsefalsefalse5falsetruefalse00falsefalsefalse6falsetruefalse00falsefalsefalse7falsetruefalse00falsefalsefalse8falsetruefalse00falsefalsefalse9truetruefalse0.010.01falsefalsefalse10falsetruefalse00falsefalsefalse11truetruefalse0.010.01falsefalsefalsenum:percentItemTypepureSale of Receivables, Fixed Rate Used in CalculationNo definition available.false0Fixed rate used when selling receivables8false 4us-gaap_EquityMethodInvestmentOwnershipPercentageus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsetruefalse00falsefalsefalse2falsetruefalse00falsefalsefalse3falsetruefalse00falsefalsefalse4falsetruefalse00falsefalsefalse5falsetruefalse00falsefalsefalse6falsetruefalse00falsefalsefalse7falsetruefalse00falsefalsefalse8falsetruefalse00falsefalsefalse9falsetruefalse00falsefalsefalse10truetruefalse0.6250.625falsefalsefalse11falsetruefalse00falsefalsefalsenum:percentItemTypepureThe percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 159 -Paragraph 18 -Subparagraph f -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 20 -Subparagraph a (1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Equity ownership interest rate9false 4us-gaap_SeniorLongTermNotesus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse150000000150falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryCarrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 false2Senior secured credit facility10false 4us-gaap_LineOfCreditFacilityExpirationDate1us-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002016-11-01falsefalsetrue2falsefalsefalse00falsefalsefalse3falsefalsefalse002013-11-01falsefalsetrue4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse002014-08-01falsefalsetrue8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalsexbrli:dateItemTypedateDate the credit facility terminates, in CCYY-MM-DD format.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false0Line of credit facility, expiration date11false 4us-gaap_VariableInterestEntityOwnershipPercentageus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsetruefalse00falsefalsefalse2falsetruefalse00falsefalsefalse3falsetruefalse00falsefalsefalse4falsetruefalse00falsefalsefalse5falsetruefalse00falsefalsefalse6truetruefalse0.090.09falsefalsefalse7falsetruefalse00falsefalsefalse8falsetruefalse00falsefalsefalse9falsetruefalse00falsefalsefalse10falsetruefalse00falsefalsefalse11falsetruefalse00falsefalsefalsenum:percentItemTypepurePercentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 5A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=7880789&loc=SL6759159-111685 false0Ownership interest in OVEC12false 4us-gaap_DebtInstrumentFaceAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8truefalsefalse300000000300USD$falsetruefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 21 -Paragraph 16, 20 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Debt instrument, face amountfalseVariable Interest Entities (Narrative) (Details) (USD $)MillionsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.duke-energy.com/role/DisclosureVariableInterestEntitiesNarrativeDetails1112