Regulatory Matters (Schedule of MISO Exit fees)(Details) (Duke Energy Ohio [Member], RTO Realignment [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Duke Energy Ohio [Member] | RTO Realignment [Member]
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 95
Restructuring reserve, accrual adjustment	1
Cash reductions	(1)
Balance, end of period	$ 95	[1]

[1] As of March 31, 2014, $74 million is recorded as a Regulatory asset on Duke Energy Ohio's Condensed Consolidated Balance Sheets.