Employee Benefit Plans (Contributions To Defined Benefit Pension Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Contribution to qualified pension plan	$ 304	$ 200	$ 400
Anticipated contribution	350
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to qualified pension plan	0	33	158
Anticipated contribution	0
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to qualified pension plan	346	334	129
Anticipated contribution	320
Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to qualified pension plan	141	217	95
Anticipated contribution	94
Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to qualified pension plan	128	112	34
Anticipated contribution	121
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to qualified pension plan	0	48	45
Anticipated contribution	18
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to qualified pension plan	0	52	46
Anticipated contribution	$ 0