Condensed Consolidated Statements Of Equity and Comprehensive Income (USD $) In Millions, except Share data	Duke Energy Corp [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Deficit) [Member]	Foreign Currency Adjustments [Member]	Net Gains (Losses) on Cash Flow Hedges [Member]	Other Equity [Member]	Pension And OPEB Related Adjustments To AOCI [Member]	Common Stockholders' Equity [Member]	Noncontrolling Interests [Member]	Total
Balance at Dec. 31, 2010		$ 1	$ 21,023	$ 1,496	$ 97	$ (18)	$ (17)	$ (60)	$ 22,522	$ 131	$ 22,653
Balance (in shares) at Dec. 31, 2010		1,329,000,000
Net income	299			511					511	2	513
Other comprehensive income, net of tax	60				31	3	3	(9)	28		28
Total comprehensive income	359
Common stock issuances, including dividend reinvestment and employee benefits (in shares)		2,000,000
Common stock issuances, including dividend reinvestment and employee benefits			4						4		4
Common stock dividends				(331)					(331)		(331)
Changes in noncontrolling interest in subsidiaries										(11)	(11)
Balance at Mar. 31, 2011		1	21,027	1,676	128	(15)	(14)	(69)	22,734	122	22,856
Balance (in shares) at Mar. 31, 2011		1,331,000,000
Balance at Dec. 31, 2011		1	21,132	1,873	(45)	(71)	(9)	(109)	22,772	93	22,865
Balance (in shares) at Dec. 31, 2011		1,336,000,000									1,336,000,000
Net income				295					295	4	299
Other comprehensive income, net of tax					44	12		4	60		60
Common stock issuances, including dividend reinvestment and employee benefits (in shares)		2,000,000
Common stock issuances, including dividend reinvestment and employee benefits			(11)						(11)		(11)
Common stock dividends				(335)					(335)		(335)
Balance at Mar. 31, 2012		$ 1	$ 21,121	$ 1,833	$ (1)	$ (59)	$ (9)	$ (105)	$ 22,781	$ 97	$ 22,878
Balance (in shares) at Mar. 31, 2012		1,338,000,000									1,338,000,000