Related Party Transactions (Narrative)(Details) (USD $) In Millions, unless otherwise specified					3 Months Ended			3 Months Ended			1 Months Ended			1 Months Ended
	Mar. 31, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Mar. 31, 2013 Progress Energy [Member]	Dec. 31, 2012 Progress Energy [Member]	Mar. 31, 2013 Duke Energy Progress [Member]	Mar. 31, 2012 Duke Energy Progress [Member]	Dec. 31, 2012 Duke Energy Progress [Member]	Mar. 31, 2013 Duke Energy Florida [Member]	Mar. 31, 2012 Duke Energy Florida [Member]	Dec. 31, 2012 Duke Energy Florida [Member]	Jan. 31, 2012 Duke Energy Ohio [Member]	Mar. 31, 2013 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Jan. 31, 2012 Duke Energy Indiana [Member]	Mar. 31, 2013 Duke Energy Indiana [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Mar. 31, 2013 DECAM [Member]	Dec. 31, 2012 DECAM [Member]
Related Party Transaction [Line Items]
DECAM Intercompany Loan Receivable	$ 397	$ 382	$ 20	$ 0				$ 0		$ 207		$ 4	$ 1
Dividends paid to parent					0	(175)		0	(105)
Transfer of Vermillion generation station											28			26
DECAM Intercompany Loan Payable			$ 980	$ 455	$ 38		$ 364	$ 238		$ 0		$ 337	$ 245		$ 27	$ 81	$ 99	$ 79