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This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Segment assets185false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse108false USDtruefalse$FROM_Apr01_2013_TO_Jun30_2013_dei_LegalEntityAxis_DukeEnergyIndianaMemberhttp://www.sec.gov/CIK0001326160duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseDuke Energy Indiana [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyIndianaMemberdei_LegalEntityAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Indiana [Member]186true 4us-gaap_SegmentReportingInformationProfitLossAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information, Profit (Loss) [Abstract]187false 5us-gaap_SalesRevenueNetus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse700000000700USD$falsefalsefalse2truefalsefalse685000000685USD$falsefalsefalse3truefalsefalse14240000001424USD$falsefalsefalse4truefalsefalse13730000001373USD$falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryTotal revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 false2Operating revenues188false 5us-gaap_ProfitLossus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse8200000082USD$falsefalsefalse2truefalsefalse7700000077USD$falsefalsefalse3truefalsefalse172000000172USD$falsefalsefalse4truefalsefalse-90000000-90USD$falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4K -URI http://asc.fasb.org/extlink&oid=18733213&loc=SL4591552-111686 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 -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 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a -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 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(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. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=18733213&loc=SL4591551-111686 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 -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 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 5 -Subparagraph b -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. false2Net Income (Loss)189true 4duk_SegmentReportingInformationAssetsAbstractduk_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information Assets [Abstract]190false 5us-gaap_Assetsus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse1012400000010124USD$falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse1012400000010124USD$falsefalsefalse4falsefalsefalse00falsefalsefalse5truefalsefalse1000800000010008USD$falsefalsefalsexbrli:monetaryItemTypemonetarySum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.18) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 7 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Concepts (CON) -Number 6 -Paragraph 25 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Segment assets191false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse113false USDtruefalse$FROM_Apr01_2013_TO_Jun30_2013_dei_LegalEntityAxis_DukeEnergyIndianaMember_us-gaap_StatementBusinessSegmentsAxis_AllOtherSegmentsMemberhttp://www.sec.gov/CIK0001326160duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseDuke Energy Indiana [Member]dei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldiduk_DukeEnergyIndianaMemberdei_LegalEntityAxisexplicitMemberfalsefalseAll Other Segments [Member]us-gaap_StatementBusinessSegmentsAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_AllOtherSegmentsMemberus-gaap_StatementBusinessSegmentsAxisexplicitMemberUSDollarStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Duke Energy Indiana [Member] | All Other Segments [Member]192true 4us-gaap_SegmentReportingInformationProfitLossAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Segment Reporting Information, Profit (Loss) [Abstract]193false 5duk_SegmentIncomeduk_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse-4000000-4USD$falsetruefalse2truefalsefalse-1000000-1USD$falsetruefalse3truefalsefalse-8000000-8USD$falsetruefalse4truefalsefalse-5000000-5USD$falsetruefalse5falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetarySegment income is the measure used by management of Duke Energy to evaluate financial performance across business segmentsNo definition available.false2Segment income1On May 1, 2013, the PUCO approved a Duke Energy Ohio settlement agreement that provides for a net annual increase in electric distribution revenues of $49 million, beginning in May 2013. This rate increase impacts USFE&G.2On May 30, 2013, the NCUC approved a Duke Energy Progress settlement agreement that included a $147 million increase in rates in the first year, beginning on June 1, 2013. This rate increase impacts USFE&G.3On May 30, 2013, the NCUC approved a Duke Energy Progress settlement agreement that included a $147 million increase in rates in the first year, beginning on June 1, 2013. This rate increase impacts USFE&G.4On January 25, 2012 and January 27, 2012, the Duke Energy Carolinas' South Carolina and North Carolina rate case settlement agreements were approved by the PSCSC and NCUC, respectively. Among other things, the rate case settlements included an annual base rate increase of $309 million in North Carolina and a $93 million annual base rate increase in South Carolina, both beginning in February 2012. These rate increases impact USFE&G.5USFE&G recorded an after-tax impairment charge of $180 million, net of tax of $115 million, related to Duke Energy Florida's Crystal River Unit 3. See Note 4 for additional information.6USFE&G recorded an after-tax impairment charge of $13 million, net of tax of $9 million, related to the letter Duke Energy Progress filed with the NRC requesting the NRC to suspend its review activities associated with the combined construction and operating license (COL) at the Shearon Harris Nuclear Station (Harris) site. USFE&G also recorded an after-tax impairment charge of $44 million, net of tax of $21 million, related to the write-off of the wholesale portion of Levy investments at Duke Energy Florida in accordance with the 2013 Settlement. See Note 4 for additional information. 7Other includes after-tax costs to achieve the merger with Progress Energy of $51 million, net of tax of $31 million. See Note 2 for additional information about the merger.8USFE&G recorded an after-tax impairment charge of $13 million, net of tax of $9 million, related to the letter Duke Energy Progress filed with the NRC requesting the NRC to suspend its review activities associated with the combined construction and operating license (COL) at the Shearon Harris Nuclear Station (Harris) site. USFE&G also recorded an after-tax impairment charge of $44 million, net of tax of $21 million, related to the write-off of the wholesale portion of Levy investments at Duke Energy Florida in accordance with the 2013 Settlement. See Note 4 for additional information.9Other includes after-tax costs to achieve the merger with Progress Energy of $85 million, net of tax of $52 million. See Note 2 for additional information about the merger.10USFE&G recorded an after-tax impairment charge of $268 million, net of tax of $152 million, related to Duke Energy Indiana's Edwardsport Integrated Gasification Combined Cycle (IGCC) project. USFE&G also recorded the reversal of expenses of $60 million, net of tax of $39 million, related to a prior year Voluntary Opportunity Plan in accordance with Duke Energy Carolinas' 2011 rate case.11On May 1, 2013, the PUCO approved a Duke Energy Ohio settlement agreement that provides for a net annual increase in electric distribution revenues of $49 million, beginning in May 2013. This rate increase impacts Franchised Electric and Gas.falseBusiness Segments (Business Segment Data) (Details) (USD $)MillionsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.duke-energy.com/role/DisclosureBusinessSegmentsBusinessSegmentDataDetails5193