Employee Benefit Plans (Information For Plans with Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Qualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	$ 679	$ 1,386
Accumulated benefit obligation	651	1,326
Fair value of plan assets	610	1,260
Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	304	331
Accumulated benefit obligation	304	331
Duke Energy Carolinas [Member] | Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	14	14
Accumulated benefit obligation	14	14
Progress Energy [Member] | Qualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	679	718
Accumulated benefit obligation	651	683
Fair value of plan assets	610	650
Progress Energy [Member] | Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	106	116
Accumulated benefit obligation	106	116
Duke Energy Progress [Member] | Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	31	35
Accumulated benefit obligation	31	35
Duke Energy Florida [Member] | Qualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	679	718
Accumulated benefit obligation	651	683
Fair value of plan assets	610	650
Duke Energy Florida [Member] | Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	43	47
Accumulated benefit obligation	43	47
Duke Energy Ohio [Member] | Qualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	123	337
Accumulated benefit obligation	115	326
Fair value of plan assets	69	308
Duke Energy Ohio [Member] | Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	3	4
Accumulated benefit obligation	3	4
Duke Energy Indiana [Member] | Qualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	203
Accumulated benefit obligation	199
Fair value of plan assets	159
Duke Energy Indiana [Member] | Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	3	3
Accumulated benefit obligation	3	3
Piedmont Natural Gas [Member] | Nonqualified Plan [Member]
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	3	4
Accumulated benefit obligation	$ 3	$ 4