Joint Ownership Of Generating And Transmission Facilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Duke Energy Carolinas Catawba Nuclear Station (Units 1 and 2) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	19.25%	[1]
Property, Plant, and Equipment	$ 880	[1]
Accumulated Depreciation	427	[1]
Construction Work in Progress	5	[1]
Duke Energy Ohio Miami Fort Station (Units 7 and 8) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	64.00%	[2]
Property, Plant, and Equipment	612	[2]
Accumulated Depreciation	190	[2]
Construction Work in Progress	4	[2]
Duke Energy Ohio W.C. Beckjord Station (Unit 6) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	37.50%	[2],[3]
Property, Plant, and Equipment		[2],[3]
Accumulated Depreciation		[2],[3]
Construction Work in Progress		[2],[3]
Duke Energy Ohio J.M. Stuart Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	39.00%	[2],[4]
Property, Plant, and Equipment	805	[2],[4]
Accumulated Depreciation	251	[2],[4]
Construction Work in Progress	17	[2],[4]
Duke Energy Ohio Conesville Station (Unit 4) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	40.00%	[2],[4]
Property, Plant, and Equipment	295	[2],[4]
Accumulated Depreciation	51	[2],[4]
Construction Work in Progress	14	[2],[4]
Duke Energy Ohio W.M. Zimmer Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	46.50%	[2]
Property, Plant, and Equipment	1,318	[2]
Accumulated Depreciation	559	[2]
Construction Work in Progress	39	[2]
Duke Energy Ohio Killen Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	33.00%	[2],[4]
Property, Plant, and Equipment	304	[2],[4]
Accumulated Depreciation	139	[2],[4]
Construction Work in Progress	3	[2],[4]
Duke Energy Ohio Vermillion [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	75.00%	[2],[5]
Property, Plant, and Equipment	174	[2],[5]
Accumulated Depreciation	61	[2],[5]
Construction Work in Progress		[2],[5]
Duke Energy Ohio Transmission [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share		[1]
Property, Plant, and Equipment	104	[1]
Accumulated Depreciation	54	[1]
Construction Work in Progress		[1]
Duke Energy Kentucky East Bend Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	69.00%	[1]
Property, Plant, and Equipment	434	[1]
Accumulated Depreciation	234	[1]
Construction Work in Progress	6	[1]
Duke Energy Indiana Gibson Station (Unit 5) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	50.05%	[1]
Property, Plant, and Equipment	305	[1]
Accumulated Depreciation	141	[1]
Construction Work in Progress	3	[1]
Duke Energy Indiana Transmission and local facilities [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share		[1]
Property, Plant, and Equipment	3,335	[1]
Accumulated Depreciation	1,448	[1]
Construction Work in Progress		[1]
International Energy Brazil-Canoas I and II [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership Share	47.20%
Property, Plant, and Equipment	332
Accumulated Depreciation	91
Construction Work in Progress

[1] Included in USFE&G segment.

[2] Included in Commercial Power segment.

[3] During the 2010 and 2009, Duke Energy Ohio recorded impairment charges to write-down its share of W.C. Beckjord Station to fair value. See Note 12 for further details.

[4] Station is not operated by Duke Energy Ohio.

[5] After receiving approval from the FERC and the IURC, on January 12, 2012, Duke Energy Ohio completed the sale its 75% ownership in the Vermillion Generating Station. Upon the close, Duke Energy Indiana and WVPA held 62.5% and 37.5% interests, respectively. See Notes 2 and 5 for further discussion of the Vermillion transaction.