Severance Rollforward (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	$ 135
Provision/adjustments	35	[1]
Cash reductions	(90)
Balance at June 30, 2013	80
Duke Energy Carolinas [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	12
Provision/adjustments	2
Cash reductions	(11)
Balance at June 30, 2013	3
Progress Energy [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	43
Provision/adjustments	40	[1]
Cash reductions	(31)
Balance at June 30, 2013	52
Duke Energy Progress [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	23
Provision/adjustments	4
Cash reductions	(15)
Balance at June 30, 2013	12
Duke Energy Florida [Member]
Restructuring Reserve [Roll Forward]
Balance at December 31, 2012	6
Provision/adjustments	30	[1]
Cash reductions	(7)
Balance at June 30, 2013	$ 29

[1] Provision / Adjustments for Duke Energy, Progress Energy and Duke Energy Florida includes $28 million of severance costs deferred related to Crystal River Unit 3.