2.4.0.8040606 - Disclosure - Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details)truefalsefalse1false USDfalsefalseFROM_Jan01_2013_TO_Jun30_2013http://www.sec.gov/CIK0001326160duration2013-01-01T00:00:002013-06-30T00:00:00USDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$1true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]2false 4us-gaap_LineOfCreditFacilityExpirationDate1us-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002016-11-01falsefalsetruexbrli:dateItemTypedateDate the credit facility terminates, in CCYY-MM-DD format.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false0Line of credit facility, expiration date3false 4duk_LineOfCreditFacilityMaximumBorrowingCapacityExtendedduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse56300000005630000000USD$falsetruefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the extended credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.No definition available.false2Extended facility size4false 4duk_LineOfCreditFacilityExpirationDate2duk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse002017-11-01falsefalsetruexbrli:dateItemTypedateDate the extended credit facility terminates, in CCYY-MM-DD format.No definition available.false0Line of credit facility, extended expiration date5false 4us-gaap_LineOfCreditFacilityAffiliatedBorrowerus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00The Duke Energy Registrants each have borrowing capacity under the master credit facility up to specified sublimits for each borrower. Duke Energy has the unilateral ability at any time to increase or decrease the borrowing sublimits of each borrower, subject to a maximum sublimit for each borrower.falsefalsefalsexbrli:stringItemTypestringIdentification of each affiliate who is permitted to utilize the line of credit (for example, a subsidiary of the reporting entity) and description of its relationship to the reporting entity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -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 3: 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, affiliated borrower6false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2false USDtruefalse$AS_OF_Jun30_2013_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Revolving Credit Facility [Member]7true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]8false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse60000000006000000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size9true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]10false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-1330000000-1330000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paper11false 5us-gaap_LettersOfCreditOutstandingAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-68000000-68000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe total amount of the contingent obligation under letters of credit outstanding as of the reporting date.No definition available.false2Outstanding letters of credit12false 5duk_TaxExemptBondsduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-240000000-240000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryIncluding the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as tax-exempt bonds.No definition available.false2Tax exempt bonds13false 5us-gaap_LineOfCreditFacilityCurrentBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse43620000004362000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Available capacity14false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse3false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_DukeEnergyCarolinasMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseDuke Energy Carolinas [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyCarolinasMemberdei_LegalEntityAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]15true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]16false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse12500000001250000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -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 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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size17true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]18false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-300000000-300000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paper19false 5us-gaap_LettersOfCreditOutstandingAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-7000000-7000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe total amount of the contingent obligation under letters of credit outstanding as of the reporting date.No definition available.false2Outstanding letters of credit20false 5duk_TaxExemptBondsduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-75000000-75000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryIncluding the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as tax-exempt bonds.No definition available.false2Tax exempt bonds21false 5us-gaap_LineOfCreditFacilityCurrentBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse868000000868000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.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 false2Available capacity22false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse4false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_DukeEnergyProgressMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseDuke Energy Progress [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyProgressMemberdei_LegalEntityAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Progress [Member] | Revolving Credit Facility [Member]23true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]24false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse750000000750000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size25true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]26false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-197000000-197000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paper27false 5us-gaap_LettersOfCreditOutstandingAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-2000000-2000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe total amount of the contingent obligation under letters of credit outstanding as of the reporting date.No definition available.false2Outstanding letters of credit28false 5us-gaap_LineOfCreditFacilityCurrentBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse551000000551000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.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 false2Available capacity29false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse5false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_DukeEnergyFloridaMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseDuke Energy Florida [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyFloridaMemberdei_LegalEntityAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Florida [Member] | Revolving Credit Facility [Member]30true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]31false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse750000000750000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size32true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]33false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-8000000-8000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paper34false 5us-gaap_LettersOfCreditOutstandingAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-1000000-1000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe total amount of the contingent obligation under letters of credit outstanding as of the reporting date.No definition available.false2Outstanding letters of credit35false 5us-gaap_LineOfCreditFacilityCurrentBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse741000000741000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.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 false2Available capacity36false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse6false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_DukeEnergyOhioMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseDuke Energy Ohio [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyOhioMemberdei_LegalEntityAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Ohio [Member] | Revolving Credit Facility [Member]37true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]38false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse750000000750000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size39true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]40false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-445000000-445000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paper41false 5duk_TaxExemptBondsduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-84000000-84000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryIncluding the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as tax-exempt bonds.No definition available.false2Tax exempt bonds42false 5us-gaap_LineOfCreditFacilityCurrentBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse221000000221000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.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 false2Available capacity43false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse7false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_DukeEnergyOhioMember_duk_ConsolidationItemsAxis_DukeEnergyKentuckyMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseDuke Energy Ohio [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyOhioMemberdei_LegalEntityAxisexplicitMemberfalsefalseDuke Energy Kentucky [Member]duk_ConsolidationItemsAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyKentuckyMemberduk_ConsolidationItemsAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Ohio [Member] | Duke Energy Kentucky [Member] | Revolving Credit Facility [Member]44true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]45false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse100000000100000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size46false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse8false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_DukeEnergyIndianaMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseDuke Energy Indiana [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyIndianaMemberdei_LegalEntityAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Indiana [Member] | Revolving Credit Facility [Member]47true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]48false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse750000000750000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -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 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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size49true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]50false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-150000000-150000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paper51false 5duk_TaxExemptBondsduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-81000000-81000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryIncluding the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as tax-exempt bonds.No definition available.false2Tax exempt bonds52false 5us-gaap_LineOfCreditFacilityCurrentBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse519000000519000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Available capacity53false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse9false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_ParentCompanyMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseParent Company [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ParentCompanyMemberdei_LegalEntityAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Parent Company [Member] | Revolving Credit Facility [Member]54true 3us-gaap_LineOfCreditFacilityLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Line of Credit Facility [Line Items]55false 4us-gaap_LineOfCreditFacilityMaximumBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse17500000001750000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryMaximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -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 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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Facility size56true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]57false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-230000000-230000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paper58false 5us-gaap_LettersOfCreditOutstandingAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-58000000-58000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe total amount of the contingent obligation under letters of credit outstanding as of the reporting date.No definition available.false2Outstanding letters of credit59false 5us-gaap_LineOfCreditFacilityCurrentBorrowingCapacityus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse14620000001462000000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 false2Available capacity60false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse10false USDtruefalse$AS_OF_Jun30_2013_dei_LegalEntityAxis_ParentCompanyMember_duk_ConsolidationItemsAxis_ProceedsLoanedToSubsidiaryRegistrantsMember_us-gaap_CreditFacilityAxis_RevolvingCreditFacilityMemberhttp://www.sec.gov/CIK0001326160instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseParent Company [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ParentCompanyMemberdei_LegalEntityAxisexplicitMemberfalsefalseProceeds Loaned To Subsidiary Registrants [Member]duk_ConsolidationItemsAxisxbrldihttp://xbrl.org/2006/xbrldiduk_ProceedsLoanedToSubsidiaryRegistrantsMemberduk_ConsolidationItemsAxisexplicitMemberfalsefalseRevolving Credit Facility [Member]us-gaap_CreditFacilityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_RevolvingCreditFacilityMemberus-gaap_CreditFacilityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member] | Revolving Credit Facility [Member]61true 4duk_ReductionToBackstopIssuancesAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Reduction to Backstop Issuances [Abstract]62false 5duk_NotesPayableAndCommercialPaperduk_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse450000000450000000USD$falsetruefalsexbrli:monetaryItemTypemonetaryNotes Payable And Commercial PaperNo definition available.false2Notes payable and commercial paperfalseDebt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) (USD $)NoRoundingUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.duke-energy.com/role/DebtAndCreditFacilitiesScheduleOfLineOfCreditFacilitiesDetails162