Commitments and Contingencies (Schedule of Environmental Loss Contingencies)(Details) (USD $) In Millions, unless otherwise specified	3 Months Ended							3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Minimum [Member]	Mar. 31, 2014 Maximum [Member]	Mar. 31, 2014 Duke Energy Carolinas [Member]	Mar. 31, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Mar. 31, 2014 Duke Energy Carolinas [Member] Minimum [Member]	Mar. 31, 2014 Duke Energy Carolinas [Member] Maximum [Member]	Mar. 31, 2014 Progress Energy [Member]	Mar. 31, 2013 Progress Energy [Member]	Mar. 31, 2014 Progress Energy [Member] Minimum [Member]	Mar. 31, 2014 Progress Energy [Member] Maximum [Member]	Mar. 31, 2014 Duke Energy Progress [Member]	Mar. 31, 2013 Duke Energy Progress [Member]	Mar. 31, 2014 Duke Energy Progress [Member] Minimum [Member]	Mar. 31, 2014 Duke Energy Progress [Member] Maximum [Member]	Mar. 31, 2014 Duke Energy Florida [Member]	Mar. 31, 2013 Duke Energy Florida [Member]	Mar. 31, 2014 Duke Energy Florida [Member] Minimum [Member]	Mar. 31, 2014 Duke Energy Florida [Member] Maximum [Member]	Mar. 31, 2014 Duke Energy Ohio [Member]	Mar. 31, 2013 Duke Energy Ohio [Member]	Mar. 31, 2014 Duke Energy Ohio [Member] Minimum [Member]	Mar. 31, 2014 Duke Energy Ohio [Member] Maximum [Member]	Mar. 31, 2014 Duke Energy Indiana [Member]	Mar. 31, 2013 Duke Energy Indiana [Member]	Mar. 31, 2014 Duke Energy Indiana [Member] Minimum [Member]	Mar. 31, 2014 Duke Energy Indiana [Member] Maximum [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Beginning balance	$ 79	$ 75			$ 11	$ 12	$ 12			$ 27	$ 33			$ 8	$ 14			$ 19	$ 19			$ 27	$ 15			$ 7	$ 8
Provision/adjustments	3	2			0					3	1			2	0			1	1			0	0			0	0
Cash reductions	(1)	(6)								(1)	(2)			0	(1)			(1)	(1)			0	(2)			0	(1)
Ending balance	81	71			11	12	12			29	32			10	13			19	19			27	13			7	7
Estimated cost of complying with EPA Mercury and Air Toxics Standards			$ 525	$ 625				$ 40	$ 50			$ 25	$ 40			$ 10	$ 15			$ 15	$ 25			$ 35	$ 50			$ 425	$ 485