Accumulated Other Comprehensive Income Changes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended											3 Months Ended												3 Months Ended								3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Accumulated Translation Adjustment [Member]	Mar. 31, 2012 Accumulated Translation Adjustment [Member]	Mar. 31, 2013 Net Gains (Losses) on Cash Flow Hedges [Member]	Mar. 31, 2012 Net Gains (Losses) on Cash Flow Hedges [Member]	Mar. 31, 2012 Accumulated Net Unrealized Investment Gain (Loss) [Member]	Mar. 31, 2013 Pension And OPEB Related Adjustments To AOCI [Member]	Mar. 31, 2012 Pension And OPEB Related Adjustments To AOCI [Member]	Mar. 31, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Mar. 31, 2013 Progress Energy [Member]	Mar. 31, 2012 Progress Energy [Member]	Mar. 31, 2013 Progress Energy [Member] Net Gains (Losses) on Cash Flow Hedges [Member]	Mar. 31, 2012 Progress Energy [Member] Net Gains (Losses) on Cash Flow Hedges [Member]	Mar. 31, 2013 Progress Energy [Member] Pension And OPEB Related Adjustments To AOCI [Member]	Mar. 31, 2012 Progress Energy [Member] Pension And OPEB Related Adjustments To AOCI [Member]	Mar. 31, 2013 Duke Energy Progress [Member]	Mar. 31, 2012 Duke Energy Progress [Member]	Mar. 31, 2012 Duke Energy Progress [Member] Net Gains (Losses) on Cash Flow Hedges [Member]	Mar. 31, 2012 Duke Energy Florida [Member]	Mar. 31, 2013 Duke Energy Florida [Member]	Dec. 31, 2012 Duke Energy Florida [Member]	Mar. 31, 2012 Duke Energy Florida [Member] Net Gains (Losses) on Cash Flow Hedges [Member]	Mar. 31, 2013 Duke Energy Ohio [Member]	Mar. 31, 2012 Duke Energy Ohio [Member]	Mar. 31, 2013 Duke Energy Ohio [Member] Pension And OPEB Related Adjustments To AOCI [Member]	Mar. 31, 2012 Duke Energy Ohio [Member] Pension And OPEB Related Adjustments To AOCI [Member]	Mar. 31, 2012 Duke Energy Indiana [Member]	Mar. 31, 2013 Duke Energy Indiana [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Mar. 31, 2012 Duke Energy Indiana [Member] Net Gains (Losses) on Cash Flow Hedges [Member]
Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax [Abstract]
Accumulated other comprehensive income (loss), net of tax, beginning balance	$ (306)	$ (234)	$ (116)	$ (45)	$ (100)	$ (71)	$ (9)	$ (90)	$ (109)	$ (16)	$ (16)	$ (67)						$ 0				$ 0	$ 0		$ (1)					$ 5	$ 5
Other comprehensive income loss before reclassifications, net of tax	17	62	4	44	10	13	1	3	4
Reclassification from accumulated other comprehensive income current period, net of tax		(2)				(1)	(1)
Other comprehensive income (loss), net of tax	17	60	4	44	10	12		3	4			2	5	1	4	1	1	0	5	5	1			1	1	1	1	1	(1)			(1)
Accumulated other comprehensive income (loss), net of tax, ending balance	$ (289)	$ (174)	$ (112)	$ (1)	$ (90)	$ (59)	$ (9)	$ (87)	$ (105)	$ (16)	$ (16)	$ (65)						$ 0				$ 0	$ 0		$ 0					$ 5	$ 5