Fair Value Of Financial Assets And Liabilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified				3 Months Ended	12 Months Ended		12 Months Ended				12 Months Ended																					12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Duke Energy Carolinas [Member]	Sep. 30, 2011 Progress Energy [Member]	Dec. 31, 2012 Progress Energy [Member]	Dec. 31, 2011 Progress Energy [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member]	Dec. 31, 2011 Progress Energy Carolinas [Member]	Dec. 31, 2012 Progress Energy Florida [Member]	Dec. 31, 2011 Progress Energy Florida [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Dec. 31, 2011 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Dec. 31, 2011 Duke Energy Indiana [Member]	Dec. 31, 2012 Not Designated As Hedging Instrument [Member]	Dec. 31, 2011 Not Designated As Hedging Instrument [Member]	Dec. 31, 2012 Not Designated As Hedging Instrument [Member] Duke Energy Carolinas [Member]	Dec. 31, 2012 Not Designated As Hedging Instrument [Member] Progress Energy [Member]	Dec. 31, 2011 Not Designated As Hedging Instrument [Member] Progress Energy [Member]	Dec. 31, 2012 Not Designated As Hedging Instrument [Member] Progress Energy Carolinas [Member]	Dec. 31, 2011 Not Designated As Hedging Instrument [Member] Progress Energy Carolinas [Member]	Dec. 31, 2012 Not Designated As Hedging Instrument [Member] Progress Energy Florida [Member]	Dec. 31, 2011 Not Designated As Hedging Instrument [Member] Progress Energy Florida [Member]	Dec. 31, 2012 Not Designated As Hedging Instrument [Member] Duke Energy Ohio [Member]	Dec. 31, 2011 Not Designated As Hedging Instrument [Member] Duke Energy Ohio [Member]	Dec. 31, 2012 Not Designated As Hedging Instrument [Member] Duke Energy Indiana [Member]	Dec. 31, 2011 Not Designated As Hedging Instrument [Member] Duke Energy Indiana [Member]	Dec. 31, 2012 CVOs [Member] Progress Energy [Member]	Dec. 31, 2011 CVOs [Member] Other Current Liabilities [Member]	Dec. 31, 2012 CVOs [Member] Deferred Credits And Other Liabilities [Member]	Dec. 31, 2012 Interest Rate Current [Member]	Dec. 31, 2012 Auction Rate Securities [Member] Duke Energy Corp [Member]	Dec. 31, 2012 Auction Rate Securities [Member] Discounted Cash Flow [Member] Risk Adjusted Discount Rates [Member]
Auction Rate Securities [Abstract]
Auction rate securities sold in period					$ (4)		$ (4)				$ (1)	$ 14	$ 52	$ 21																		$ (55)
Level 3 ARS Assumptions																															0.30%		4.20%
Contingent Value Obligations [Abstract]
CVO trust																												11
CVO purchase price																												0.75
CVO mark-to-market				(59)
CVO liability	$ 917	$ 473	$ 12		$ 440	$ 799	$ 166	$ 248	$ 270	$ 499	$ 199	$ 245	$ 63	$ 68	$ 798	$ 386	$ 12	$ 437	$ 703	$ 164	$ 201	$ 269	$ 488	$ 199	$ 245	$ 63	$ 68		$ 14	$ 4