Employee Benefit Plans (Information For Plans with Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - Pension Plan - Qualified Plan - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	$ 4,914
Accumulated benefit obligation	4,856
Fair value of plan assets	4,837
Progress Energy
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	828
Accumulated benefit obligation	796
Fair value of plan assets	783
Duke Energy Florida
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	828
Accumulated benefit obligation	796
Fair value of plan assets	783
Duke Energy Ohio
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	184	$ 155
Accumulated benefit obligation	176	146
Fair value of plan assets	96	79
Duke Energy Indiana
Information For Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Projected benefit obligation	293	260
Accumulated benefit obligation	285	252
Fair value of plan assets	$ 183	$ 177