Acquisitions, Dispositions and Sales of Other Assets Acquisitions, Dispositions and Sales of Other Assets (Plants in Disposal Group) (Details) (Duke Energy Ohio [Member])	12 Months Ended
	Dec. 31, 2014 MW
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	9,225
Owned Plant Capacity	5,884
J M Stuart Station [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	2,308
Owned Plant Capacity	900
Jointly Owned Utility Plant, Proportionate Ownership Share	39.00%
W M Zimmer Station [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	1,300
Owned Plant Capacity	605
Jointly Owned Utility Plant, Proportionate Ownership Share	46.50%
Hanging Rock [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	1,226
Owned Plant Capacity	1,226
Jointly Owned Utility Plant, Proportionate Ownership Share	100.00%
Miami Fort Station Units 7 And 8 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	1,020
Owned Plant Capacity	652
Jointly Owned Utility Plant, Proportionate Ownership Share	64.00%
Conesville Station (Unit 4) [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	780
Owned Plant Capacity	312
Jointly Owned Utility Plant, Proportionate Ownership Share	40.00%
Washington [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	617
Owned Plant Capacity	617
Jointly Owned Utility Plant, Proportionate Ownership Share	100.00%
Fayette [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	614
Owned Plant Capacity	614
Jointly Owned Utility Plant, Proportionate Ownership Share	100.00%
Killen Station [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	600
Owned Plant Capacity	198
Jointly Owned Utility Plant, Proportionate Ownership Share	33.00%
Lee [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	568
Owned Plant Capacity	568
Jointly Owned Utility Plant, Proportionate Ownership Share	100.00%
Dicks Creek [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	136
Owned Plant Capacity	136
Jointly Owned Utility Plant, Proportionate Ownership Share	100.00%
Miami Fort [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Plant Capacity	56
Owned Plant Capacity	56
Jointly Owned Utility Plant, Proportionate Ownership Share	100.00%