Debt And Credit Facilities (Details) (USD $)	3 Months Ended						9 Months Ended
	Sep. 30, 2011		Aug. 31, 2011	Apr. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Maximum [Member]	Sep. 30, 2011 Duke Energy Master Credit Facility Expiring In June 2012 [Member]	Oct. 31, 2011 Duke Energy Master Credit Facility Repalcement [Member]	Sep. 30, 2011 Duke Energy Corp [Member]		Aug. 31, 2011 Duke Energy Corp [Member]	Dec. 31, 2010 Duke Energy Corp [Member]	Sep. 30, 2011 Duke Energy Carolinas [Member]	Dec. 31, 2010 Duke Energy Carolinas [Member]
Principal amount of senior notes			$ 500,000,000
Senior note fixed interest rate											3.55%
Demand notes, maximum amount available for sale				1,000,000,000
Secured demand notes, outstanding	30,000,000
Receivables borrowings reflected as non-recourse notes payable of VIEs									275,000,000
Credit facility, outstanding balance							3,140,000,000
Facility Size	3,137,000,000	[1]						6,000,000,000	1,097,000,000	[1]
Notes Payable and Commercial Paper	(900,000,000)	[2]							(450,000,000)	[2]
Outstanding Letters of Credit	(80,000,000)								(46,000,000)
Tax-Exempt Bonds	(285,000,000)								(25,000,000)
Line of Credit Facility, Remaining Borrowing Capacity								2,000,000,000
Available Capacity	1,872,000,000							4,000,000,000	576,000,000
Commercial Paper	450,000,000
Commercial Paper Issued During The Period	(450,000,000)
Non-Recourse Long-Term Debt	$ 959,000,000				$ 976,000,000				$ 470,000,000			$ 492,000,000	$ 300,000,000	$ 300,000,000
Debt to total capitalization ratio, for each borrower						65

[1] Represents the sub limit of each borrower at September 30, 2011. The Duke Energy Ohio sub limit includes $100 million for Duke Energy Kentucky.

[2] Duke Energy issued $450 million of Commercial Paper and loaned the proceeds through the money pool to Duke Energy Carolinas and Duke Energy Indiana (see money pool table above). The balances are classified as long-term borrowings within Long-term Debt in Duke Energy Carolinas' and Duke Energy Indiana's Condensed Consolidated Balance Sheets. Duke Energy issued an additional $450 million of Commercial Paper in the third quarter of 2011. The balance is classified as Notes payable and commercial paper on Duke Energy's Condensed Consolidated Balance Sheets.