Other Postretirement Benefits - Net Periodic Postretirement Benefit Costs (Details) - Other Postretirement Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 13	$ 14	$ 18
Interest cost on accumulated other postretirement benefit obligation	47	57	35
Expected return on plan assets	(68)	(70)	(72)
Recognition of net actuarial loss/(gain)	(20)	(16)	(14)
Recognition of prior service credit	(1)	(2)	(1)
TOTAL PERIODIC POSTRETIREMENT BENEFIT COST/(CREDIT)	(29)	(17)	(34)
Cost capitalized	(6)	(6)	(8)
Reconciliation to rate level	16	4	29
Total credit recognized	(19)	(19)	(13)
CECONY
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	12	15
Interest cost on accumulated other postretirement benefit obligation	40	49	30
Expected return on plan assets	(55)	(56)	(58)
Recognition of net actuarial loss/(gain)	(13)	(8)	(9)
Recognition of prior service credit	0	0	0
TOTAL PERIODIC POSTRETIREMENT BENEFIT COST/(CREDIT)	(18)	(3)	(22)
Cost capitalized	(5)	(5)	(7)
Reconciliation to rate level	13	(2)	24
Total credit recognized	$ (10)	$ (10)	$ (5)