Income Taxes (Components Of Income Tax Expense) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Total deferred income taxes	$ 602		$ 741		$ 941
Total income tax expense from continuing operations	752		890		758
Total income tax expense included in Consolidated Statements of Operations	752		890		758
Uncertain tax benefits relating to temporary differences	43		392		91
Parent Company [Member]
Total income tax expense included in Consolidated Statements of Operations	(64)		(118)		(59)
Duke Energy Corp [Member]
Current Federal taxes	(37)		(5)		(271)
Current State taxes	21		39		3
Current Foreign taxes	164		125		96
Total current income taxes	148		159		(172)
Deferred Federal taxes	526		639		767
Deferred State taxes	56		83		148
Deferred Foreign taxes	32		20		27
Total deferred income taxes	614		742		942
Investment tax credit amortization	(10)		(11)		(12)
Total income tax expense from continuing operations			890		758
Total income tax benefit from discontinued operations			(1)		(2)
Total income tax expense included in Consolidated Statements of Operations	$ 752	[1]	$ 889	[2]	$ 756	[3]

[1] Included in the "Total current income taxes" line above are uncertain tax benefits relating primarily to certain temporary differences of $43 million at Duke Energy, $43 million at Duke Energy Carolinas, $3 million at Duke Energy Ohio and $3 million at Duke Energy Indiana. The offset to these temporary differences are included in the "Total deferred income taxes" line above.

[2] Included in the "Total current income taxes" line above are uncertain tax benefits relating primarily to certain temporary differences of $392 million at Duke Energy, $300 million at Duke Energy Carolinas, $3 million at Duke Energy Ohio and $7 million at Duke Energy Indiana. The offset to these temporary differences are included in the "Total deferred income taxes" line above.

[3] Included in the "Total current income taxes" line above are uncertain tax benefits relating primarily to certain temporary differences of $91 million at Duke Energy, uncertain tax expenses of $42 million, $22 million and $20 million at Duke Energy Carolinas, Duke Energy Ohio, and Duke Energy Indiana, respectively. The offset to these temporary differences are included in the "Total deferred income taxes" line above.