Goodwill (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2013

Dec. 31, 2012

Finite-Lived Intangible Assets [Line Items]

Goodwill By Reportable Operating Segment

(in millions)	USFE&G		Commercial Power		International Energy		Total
Balance at December 31, 2012:
Goodwill	$	15,950	$	933	$	353	$	17,236
Accumulated impairment charges		―		(871)		―		(871)
Balance at December 31, 2012, as adjusted for accumulated impairment charges		15,950		62		353		16,365

Duke Energy Ohio [Member]

Finite-Lived Intangible Assets [Line Items]

Goodwill By Reportable Operating Segment

Balance at March 31, 2013:
Goodwill		1,137		1,188		2,325
Accumulated impairment charges		(216)		(1,188)		(1,404)
Balance at March 31, 2013, as adjusted for accumulated impairment charges	$	921	$	―	$	921

(in millions)	Franchised Electric & Gas		Commercial Power		Total
Balance at December 31, 2012:
Goodwill	$	1,137	$	1,188	$	2,325
Accumulated impairment charges		(216)		(1,188)		(1,404)
Balance at December 31, 2012, as adjusted for accumulated impairment charges		921		―		921