Debt And Credit Facilities (Narrative) (Details) (USD $)	1 Months Ended																12 Months Ended
	Nov. 30, 2011	Aug. 31, 2011	Mar. 31, 2010	Dec. 31, 2011	Apr. 30, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Duke Energy Corp [Member]	Dec. 31, 2010 Duke Energy Corp [Member]	Dec. 31, 2011 Duke Energy Carolinas [Member]	Dec. 31, 2010 Duke Energy Carolinas [Member]	Dec. 31, 2011 Cinergy Receivables [Member]	Dec. 31, 2011 Green Frontier Wind Power, LLC [Member]	Dec. 31, 2010 Green Frontier Wind Power, LLC [Member]	May 31, 2010 Green Frontier Wind Power, LLC [Member]	Dec. 31, 2010 Top Of The World Wind Energy, LLC [Member]	Dec. 31, 2011 Duke Energy Master Credit Facility expiring in November 2016 [Member]
Principal amount of senior notes	$ 500,000,000	$ 500,000,000	$ 450,000,000
Notes fixed interest rate	2.15%	3.55%	3.35%											3.465%		3.40%
Senior notes maturity date	Nov. 15, 2016	Sep. 15, 2021	Apr. 01, 2015
Demand notes, maximum amount available for sale					1,000,000,000
Secured demand notes, outstanding				79,000,000
Non-recourse debt relating to VIEs												273,000,000			325,000,000	193,000,000
Applicable margin													2.375%			2.50%
Credit facility, outstanding balance																	6,000,000,000
Available Capacity																	4,000,000,000
Conditional capacity					500,000,000												2,000,000,000
Non-Recourse Long-Term Debt				949,000,000		976,000,000		466,000,000	492,000,000	300,000,000	300,000,000
Other loans outstanding against cash surrender value of life insurance policies						$ 457,000,000	$ 444,000,000