Business Segments (Schedule of Revenue, By Products and Services) (Details) (USD $) In Millions, unless otherwise specified
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3 Months Ended |
12 Months Ended |
Dec. 31, 2014
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Sep. 30, 2014
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Jun. 30, 2014
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Mar. 31, 2014
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Dec. 31, 2013
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Sep. 30, 2013
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Jun. 30, 2013
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Mar. 31, 2013
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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Segment Reporting Information [Line Items] |
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Operating revenues |
$ 5,559us-gaap_SalesRevenueNet |
$ 6,395us-gaap_SalesRevenueNet |
$ 5,708us-gaap_SalesRevenueNet |
$ 6,263us-gaap_SalesRevenueNet |
$ 5,610us-gaap_SalesRevenueNet |
$ 6,217us-gaap_SalesRevenueNet |
$ 5,393us-gaap_SalesRevenueNet |
$ 5,536us-gaap_SalesRevenueNet |
$ 23,925us-gaap_SalesRevenueNet |
$ 22,756us-gaap_SalesRevenueNet |
$ 17,912us-gaap_SalesRevenueNet |
Regulated Utilities [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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22,228us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
20,871us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
16,042us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
International Energy [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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1,417us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
1,546us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
1,549us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
Commercial Power [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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255us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
254us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
299us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
Total Reportable Segments [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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23,900us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_TotalReportableSegmentsMember |
22,671us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_TotalReportableSegmentsMember |
17,890us-gaap_SalesRevenueNet / us-gaap_StatementBusinessSegmentsAxis = duk_TotalReportableSegmentsMember |
Retail Electric [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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19,007us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailElectricMember |
17,837us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailElectricMember |
13,773us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailElectricMember |
Retail Electric [Member] | Regulated Utilities [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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19,007us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
17,837us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
13,773us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
Wholesale Electric [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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3,460us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember |
3,427us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember |
2,871us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember |
Wholesale Electric [Member] | Regulated Utilities [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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1,879us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
1,720us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
1,120us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
Wholesale Electric [Member] | International Energy [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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1,326us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
1,447us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
1,444us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
Wholesale Electric [Member] | Commercial Power [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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255us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
260us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
307us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleElectricMember / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
Retail Gas [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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571us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailGasMember |
506us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailGasMember |
470us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailGasMember |
Retail Gas [Member] | Regulated Utilities [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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571us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailGasMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
506us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailGasMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
470us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_RetailGasMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
Wholesale Gas [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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91us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleGasMember |
99us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleGasMember |
105us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleGasMember |
Wholesale Gas [Member] | International Energy [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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91us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleGasMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
99us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleGasMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
105us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_WholesaleGasMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
Other Revenues [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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814us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_OtherRevenuesMember |
847us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_OtherRevenuesMember |
717us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_OtherRevenuesMember |
Other Revenues [Member] | Regulated Utilities [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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814us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_OtherRevenuesMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
847us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_OtherRevenuesMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
717us-gaap_SalesRevenueNet / us-gaap_ProductOrServiceAxis = duk_OtherRevenuesMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
Operating Segments [Member] | Regulated Utilities [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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22,271us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
20,910us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
16,080us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_RegulatedUtilitiesMember |
Operating Segments [Member] | International Energy [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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1,417us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
1,546us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
1,549us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_InternationalEnergyMember |
Operating Segments [Member] | Commercial Power [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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255us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
260us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
307us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_CommercialPowerMember |
Operating Segments [Member] | Total Reportable Segments [Member] |
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Segment Reporting Information [Line Items] |
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Operating revenues |
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$ 23,943us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_TotalReportableSegmentsMember |
$ 22,716us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_TotalReportableSegmentsMember |
$ 17,936us-gaap_SalesRevenueNet / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = duk_TotalReportableSegmentsMember |