Investments in Debt and Equity Securities (Realized Gains and Losses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
FV-NI:
Realized gains	$ 20	$ 34	$ 46	$ 145
Realized losses	36	101	82	186
AFS:
Realized gains	13	11	21	15
Realized losses	27	42	59	65
Duke Energy Carolinas
FV-NI:
Realized gains	9	18	27	93
Realized losses	18	55	47	104
AFS:
Realized gains	4	9	9	12
Realized losses	8	21	28	37
Progress Energy
FV-NI:
Realized gains	11	16	19	52
Realized losses	18	46	35	82
AFS:
Realized gains	9	2	12	3
Realized losses	19	17	31	23
Duke Energy Progress
FV-NI:
Realized gains	11	15	19	51
Realized losses	17	45	34	80
AFS:
Realized gains	8	2	11	3
Realized losses	$ 17	$ 15	$ 29	$ 20