Variable Interest Entities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended				12 Months Ended					12 Months Ended
	Dec. 31, 2012	Dec. 31, 2010 Dukenet And Alinda Capital Partners Llc Ownership In New Joint Venture [Member]	Dec. 31, 2010 Dukenet And Alinda Capital Partners Llc Ownership In New Joint Venture [Member] Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2010 Dukenet [Member]	Dec. 31, 2012 Cinergy Receivables [Member]	Dec. 31, 2011 Cinergy Receivables [Member]	Dec. 31, 2010 Cinergy Receivables [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] Derf [Member]	Dec. 31, 2012 Progress Energy [Member] FPC Capital I Trust [Member]	Dec. 31, 2012 Duke Energy Ohio [Member] Cinergy Receivables [Member]	Dec. 31, 2011 Duke Energy Ohio [Member] Cinergy Receivables [Member]	Dec. 31, 2012 Duke Energy Ohio [Member] Other Vies [Member]	Dec. 31, 2012 Duke Energy Indiana [Member] Cinergy Receivables [Member]	Dec. 31, 2011 Duke Energy Indiana [Member] Cinergy Receivables [Member]	Dec. 31, 2012 Minimum [Member] Cinergy Receivables [Member]	Dec. 31, 2012 Maximum [Member] Cinergy Receivables [Member]
Variable Interest Entity [Line Items]
Proceeds received for sale of receivables, portion received as note payable					25.00%
Minimum Equity Balance required by Cinergy Receivables					$ 3
Subordinated retained interest limitation of the total proceeds															10.00%	20.00%
Secured credit facility of variable interest entities								300
Fixed rate used when selling receivables										1.00%	2.39%		1.00%	2.39%
Equity ownership interest rate			50.00%	50.00%
Senior secured credit facility		150
Line of Credit Facility, Expiration Date	Aug. 01, 2014
Ownership interest in OVEC												9.00%
CinCap purchased power contract expiration					2016
Debt instrument, face amount									300
Capital Infusion to CRC						$ 6	$ 10