Income Tax - Schedule of Components of Income Tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
State
Current	$ (49)	$ (81)	$ 179
Deferred	182	223	6
Federal
Current	33	(17)	176
Deferred	414	198	237
Amortization of investment tax credits	(6)	(5)	(111)
Total income tax expense	574	318	487
CECONY
State
Current	(40)	(87)	(102)
Deferred	159	219	246
Federal
Current	149	(63)	(95)
Deferred	278	246	311
Amortization of investment tax credits	(2)	(1)	(2)
Total income tax expense	$ 544	$ 314	$ 358