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Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Goodwill [Roll Forward]
Foreign exchange and other changes			$ (33)
Goodwill, Acquired During Period			24
Goodwill as adjusted for accumulated impairment charges	$ 16,312		16,312		$ 16,321
Asset impairment charges	111	$ 1	111	$ 81
Regulated Utilities [Member]
Goodwill [Roll Forward]
Goodwill as adjusted for accumulated impairment charges	15,950		15,950		15,950
International [Member]
Goodwill [Roll Forward]
Foreign exchange and other changes			(33)
Goodwill as adjusted for accumulated impairment charges	274		274		307
Commercial Portfolio [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period			24
Goodwill as adjusted for accumulated impairment charges	88		88		64
Commercial Portfolio [Member] \| Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges				94
Duke Energy Ohio [Member]
Goodwill [Roll Forward]
Goodwill	920		920		920
Goodwill as adjusted for accumulated impairment charges	920		920		920
Goodwill, Impaired, Accumulated Impairment Loss	$ 216		$ 216		216
Asset impairment charges				94
Duke Energy Ohio [Member] \| Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges				94	$ 94
Duke Energy Ohio [Member] \| Commercial Portfolio [Member] \| Other VIEs [Member]
Goodwill [Roll Forward]
Asset impairment charges				$ 94