Acquisitions And Dispositions Of Businesses And Sales Of Other Assets (Cash proceeds and related net pre-tax gains related to the Sales of Asset) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Significant Acquisitions and Disposals [Line Items]
Proceeds	$ 187	[1]	$ 12	$ 160
Duke Energy Carolinas [Member]
Significant Acquisitions and Disposals [Line Items]
Proceeds	1		2	8
Duke Energy Ohio [Member]
Significant Acquisitions and Disposals [Line Items]
Proceeds	6		7	13
Duke Energy Indiana [Member]
Significant Acquisitions and Disposals [Line Items]
Proceeds	$ 0		$ 1	$ 0

[1] Duke Energy amount relates to proceeds from the disposition of non-core business assets within the Commercial Power segment for which no material gain or loss was recognized.