Income Tax - Schedule of Components of Income Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
State
Current	$ (81)	$ 179	$ 5
Deferred	223	6	324
Federal
Current	(17)	176	58
Deferred	198	237	117
Amortization of investment tax credits	(5)	(111)	(6)
Total income tax expense	318	487	498
CECONY
State
Current	(87)	(102)	0
Deferred	219	246	110
Federal
Current	(63)	(95)	170
Deferred	246	311	(23)
Amortization of investment tax credits	(1)	(2)	(2)
Total income tax expense	$ 314	$ 358	$ 255