Variable Interest Entities (Sales and Cash Flows)(Details) (Cinergy Receivables [Member], Variable Interest Entity, Not Primary Beneficiary [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Receivables sold	$ 2,251	$ 2,154	$ 2,390
Gain (loss) recognized on sale	(12)	(13)	(21)
Cash proceeds from receivables sold	2,220	2,172	2,474
Return received on retained interests	5	5	12
Collection fees received	1	1	1
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Receivables sold	2,985	2,773	2,658
Gain (loss) recognized on sale	(11)	(12)	(16)
Cash proceeds from receivables sold	2,944	2,784	2,674
Return received on retained interests	6	7	13
Collection fees received	$ 1	$ 1	$ 1