Investments in Debt and Equity Securities (Realized Gains and Losses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
FV-NI:
Realized gains	$ 127	$ 20	$ 195	$ 46
Realized losses	27	36	45	82
AFS:
Realized gains	2	13	12	21
Realized losses	22	27	36	59
Duke Energy Carolinas
FV-NI:
Realized gains	72	9	125	27
Realized losses	15	18	21	47
AFS:
Realized gains	1	4	5	9
Realized losses	11	8	17	28
Progress Energy
FV-NI:
Realized gains	55	11	70	19
Realized losses	12	18	24	35
AFS:
Realized gains	1	9	7	12
Realized losses	11	19	19	31
Duke Energy Progress
FV-NI:
Realized gains	55	11	70	19
Realized losses	12	17	24	34
AFS:
Realized gains	1	8	7	11
Realized losses	$ 10	$ 17	$ 18	$ 29