Employee Benefit Plans (Information For Plans with Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Qualified Pension Plans [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	$ 1,216	$ 702
Accumulated benefit obligation	1,158	672
Fair value of plan assets	1,151	652
Qualified Pension Plans [Member] | Progress Energy [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	611
Accumulated benefit obligation	575
Fair value of plan assets	574
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	611
Accumulated benefit obligation	575
Fair value of plan assets	574
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	307	315
Accumulated benefit obligation	298	306
Fair value of plan assets	289	302
Non-Qualified Pension Plans [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	341	337
Accumulated benefit obligation	336	333
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	16	16
Accumulated benefit obligation	16	15
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	112	116
Accumulated benefit obligation	112	116
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	33	35
Accumulated benefit obligation	33	35
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	46	61
Accumulated benefit obligation	46	61
Non-Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	4	4
Accumulated benefit obligation	4	4
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	5	5
Accumulated benefit obligation	$ 5	$ 5