Severance Rollforward (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring Liability, beginning balance	$ 32
Provision/Adjustments	171
Cash Reductions	(68)
Restructuring Liability, ending balance	135
Duke Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Liability, beginning balance	1
Provision/Adjustments	21
Cash Reductions	(10)
Restructuring Liability, ending balance	12
Progress Energy [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Liability, beginning balance	5
Provision/Adjustments	71
Cash Reductions	(33)
Restructuring Liability, ending balance	43
Progress Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Liability, beginning balance	5
Provision/Adjustments	35
Cash Reductions	(17)
Restructuring Liability, ending balance	23
Progress Energy Florida [Member]
Restructuring Cost and Reserve [Line Items]
Provision/Adjustments	12
Cash Reductions	(6)
Restructuring Liability, ending balance	$ 6