Severance Rollforward (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	$ 135
Provision/adjustments	41	[1]
Cash reductions	(114)
Balance at September 30, 2013	62
Duke Energy Carolinas [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	12
Provision/adjustments	2
Cash reductions	(12)
Balance at September 30, 2013	2
Progress Energy [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	43
Provision/adjustments	45	[1]
Cash reductions	(42)
Balance at September 30, 2013	46
Duke Energy Progress [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	23
Provision/adjustments	7
Cash reductions	(17)
Balance at September 30, 2013	13
Duke Energy Florida [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	6
Provision/adjustments	30	[1]
Cash reductions	(13)
Balance at September 30, 2013	$ 23

[1] Provision / Adjustments for Duke Energy, Progress Energy and Duke Energy Florida includes $26 million of severance costs deferred related to Crystal River Unit 3.