Investments in Debt and Equity Securities (Realized Gains and Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
FV-NI:
Realized gains	$ 25	$ 34	$ 170	$ 320
Realized losses	61	40	247	100
AFS:
Realized gains	7	17	22	51
Realized losses	40	15	105	46
Duke Energy Carolinas
FV-NI:
Realized gains	16	25	109	243
Realized losses	39	29	143	68
AFS:
Realized gains	7	10	19	35
Realized losses	20	10	57	32
Progress Energy
FV-NI:
Realized gains	9	9	61	77
Realized losses	22	11	104	32
AFS:
Realized gains		7	3	14
Realized losses	9	6	32	12
Duke Energy Progress
FV-NI:
Realized gains	9	9	60	76
Realized losses	21	11	101	31
AFS:
Realized gains		6	3	13
Realized losses	$ 9	$ 5	$ 29	$ 11