Goodwill (Goodwill By Reportable Operating Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Dec. 31, 2012
Goodwill [Line Items]
Goodwill	$ 17,242		$ 17,236
Goodwill, Acquired During Period	6	[1]
Goodwill accumulated impairment charges	(871)		(871)
Goodwill as adjusted for accumulated impairment charges	16,371		16,365
USFE&G [Member]
Goodwill [Line Items]
Goodwill	15,960		15,950
Goodwill, Acquired During Period	10	[1]
Goodwill as adjusted for accumulated impairment charges	15,960		15,950
Commercial Power [Member]
Goodwill [Line Items]
Goodwill	935		933
Goodwill, Acquired During Period	2	[1]
Goodwill accumulated impairment charges	(871)		(871)
Goodwill as adjusted for accumulated impairment charges	64		62
International [Member]
Goodwill [Line Items]
Goodwill	347		353
Goodwill, Acquired During Period	(6)	[1]
Goodwill as adjusted for accumulated impairment charges	347		353
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
Duke Energy Ohio [Member] | Franchised Electric & Gas [Member]
Goodwill [Line Items]
Goodwill	1,137		1,137
Goodwill accumulated impairment charges	(216)		(216)
Goodwill as adjusted for accumulated impairment charges	921		921
Duke Energy Ohio [Member] | DEO Commercial Power [Member]
Goodwill [Line Items]
Goodwill	1,188		1,188
Goodwill accumulated impairment charges	$ (1,188)		$ (1,188)

[1] Amounts represent purchase price adjustments related to the Progress Energy merger at USFE&G, a minor renewables acquisition at Commercial Power and the Ibener acquisition at International Energy. See Note 2 for further information on purchase price adjustments related to the Progress Energy Merger.