Regulatory Matters (Schedule Of Net Carrying Value Of Facilities As Well As The Remaining Non-current Regulatory Assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 MW
MW	3,049,000,000
Remaining net book value	$ 344	[1]
Duke Energy Carolinas [Member]
MW	1,356,000,000	[2],[3],[4]
Remaining net book value	192	[1],[2],[3],[4]
Duke Energy Indiana [Member]
MW	668,000,000	[5]
Remaining net book value	138	[1],[5]
Duke Energy Ohio [Member]
MW	1,025,000,000	[6]
Remaining net book value	$ 14	[1],[6]

[1] Included in Property, plant and equipment, net, on the Condensed Consolidated Balance Sheets unless otherwise noted.

[2] Includes Dan River Units 1 through 3, Riverbend Units 4 through 7, Lee Units 1 through 3 and Buck Units 5 and 6. Duke Energy Carolinas has committed to retire 1,667 MW in conjunction with a Cliffside air permit settlement, of which 311 MW have already been retired.

[3] Dan River was retired on April 1, 2012.

[4] Net book value of Buck Units 5 and 6 of $79 million is included in Generation facilities to be retired, net, on the Condensed Consolidated Balance Sheets.

[5] Includes Wabash River Units 2 through 6.

[6] Includes Beckjord Station and Miami Fort Unit 6. Beckjord has no remaining book value.