Related Party Transactions (Intercompany Income Taxes) (Details) - Affiliated Entity - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Duke Energy Carolinas
Related Party Transaction [Line Items]
Intercompany income tax receivable	$ 20
Intercompany income tax payable		$ 62
Progress Energy
Related Party Transaction [Line Items]
Intercompany income tax receivable	49
Duke Energy Progress
Related Party Transaction [Line Items]
Intercompany income tax payable	15	84
Duke Energy Florida
Related Party Transaction [Line Items]
Intercompany income tax receivable	9	40
Duke Energy Ohio
Related Party Transaction [Line Items]
Intercompany income tax receivable	5	19
Duke Energy Indiana
Related Party Transaction [Line Items]
Intercompany income tax payable	44	10
Piedmont
Related Party Transaction [Line Items]
Intercompany income tax payable	$ 45	$ 27