Severance (Expenses) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 34	$ 201
COBRA and healthcare expense reimbursement	2	19
Accelerated stock compensation expense	5	14
Duke Energy Carolinas [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	8	63
Progress Energy [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	19	82
Duke Energy Progress [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	14	55
Duke Energy Florida [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	5	27
Duke Energy Ohio [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	2	21
Duke Energy Ohio [Member] | Midwest Commercial Generation Involuntary Severance Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense			6
Duke Energy Indiana [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 2	$ 18