Goodwill and Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2015

Goodwill [Line Items]

Goodwill By Reportable Operating Segment

The following tables present goodwill by reportable operating segment for Duke Energy and Duke Energy Ohio.

Duke Energy

(in millions)	Regulated Utilities		International Energy			Commercial Power			Total
Balance at December 31, 2014
Goodwill	$	15,950	$	307		$	935		$	17,192
Accumulated impairment charges	—		—			(871		)	(871		)
Balance at December 31, 2014, as adjusted for accumulated impairment charges	15,950		307			64			16,321
Foreign exchange and other changes	—		(16		)	—			(16		)
Acquisitions	—		—			24			24
Balance at March 31, 2015
Goodwill	15,950		291			959			17,200
Accumulated impairment charges	—		—			(871		)	(871		)
Balance at March 31, 2015, as adjusted for accumulated impairment charges	$	15,950	$	291		$	88		$	16,329

Duke Energy Ohio [Member]

Goodwill [Line Items]

Goodwill By Reportable Operating Segment

Duke Energy Ohio

(in millions)	Regulated Utilities			Commercial Power			Total
Balance at December 31, 2014
Goodwill	$	1,136		$	1,188		$	2,324
Accumulated impairment charges	(216		)	(1,188		)	(1,404		)
Balance at December 31, 2014, as adjusted for accumulated impairment charges	920			—			920
Balance at March 31, 2015
Goodwill	1,136			1,188			2,324
Accumulated impairment charges	(216		)	(1,188		)	(1,404		)
Balance at March 31, 2015, as adjusted for accumulated impairment charges	$	920		$	—		$	920