Employee Benefit Plans (Contributions to Defined Benefit Pension Plans) (Details) (Qualified Pension Plans [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		$ 250	$ 304
Anticipated contribution	302
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Anticipated contribution	91
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		250	346
Anticipated contribution	83
Duke Energy Progress [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		63	141
Anticipated contribution	42
Duke Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions		133	128
Anticipated contribution	40
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Anticipated contribution	8
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Anticipated contribution	$ 19