Goodwill (Goodwill By Reportable Operating Segment) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Jun. 30, 2010
Goodwill [Line Items]
Goodwill	$ 17,236		$ 4,720
Goodwill, Acquired During Period	12,526
Goodwill accumulated impairment charges	(871)		(871)
Foreign Exchange and Other Changes	(10)
Goodwill as adjusted for accumulated impairment charges	16,365		3,849
Duke Energy Ohio [Member]
Goodwill [Line Items]
Goodwill	2,325		2,325
Goodwill accumulated impairment charges	(1,404)		(1,404)
Goodwill as adjusted for accumulated impairment charges	921		921
Usfe G [Member]
Goodwill [Line Items]
Goodwill	15,950		3,483
Goodwill, Acquired During Period	12,467	[1]
Goodwill as adjusted for accumulated impairment charges	15,950		3,483
Commercial Power [Member]
Goodwill [Line Items]
Goodwill	933		940	500
Goodwill accumulated impairment charges	(871)		(871)
Foreign Exchange and Other Changes	(7)
Goodwill as adjusted for accumulated impairment charges	62		69
International [Member]
Goodwill [Line Items]
Goodwill	353		297
Goodwill, Acquired During Period	59	[1]
Foreign Exchange and Other Changes	(3)
Goodwill as adjusted for accumulated impairment charges	353		297
Franchised Electric & Gas [Member] | Duke Energy Ohio [Member]
Goodwill [Line Items]
Goodwill	1,137		1,137
Goodwill accumulated impairment charges	(216)		(216)
Goodwill as adjusted for accumulated impairment charges	921		921
DEO Commercial Power [Member] | Duke Energy Ohio [Member]
Goodwill [Line Items]
Goodwill	1,188		1,188
Goodwill accumulated impairment charges	(1,188)		(1,188)
Goodwill as adjusted for accumulated impairment charges	$ 0		$ 0

[1] USFE&G amount relates to the merger with Progress Energy. International Energy amount relates to the Ibener acquisition. See Note 2 for further information.