Revenue (Remaining Performance Obligations Total) (Details) $ in Millions	Jun. 30, 2021 USD ($)
Progress Energy
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 303
Duke Energy Progress
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	28
Duke Energy Florida
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	275
Duke Energy Indiana
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	55
Piedmont
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 622