Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 161	$ 287	$ 343
Interest cost on projected benefit obligation	649	505	471
Expected return on plan assets	(1,114)	(1,168)	(1,096)
Recognition of net actuarial loss/(gain)	(232)	377	787
Recognition of prior service credit	(17)	(16)	(17)
TOTAL PERIODIC BENEFIT COST/(CREDIT)	(553)	(15)	488
Cost capitalized	(81)	(137)	(154)
Reconciliation to rate level	282	259	(226)
Total credit recognized	(352)	107	108
CECONY
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	151	270	321
Interest cost on projected benefit obligation	611	475	443
Expected return on plan assets	(1,061)	(1,109)	(1,040)
Recognition of net actuarial loss/(gain)	(219)	358	746
Recognition of prior service credit	(19)	(21)	(19)
TOTAL PERIODIC BENEFIT COST/(CREDIT)	(537)	(27)	451
Cost capitalized	(78)	(129)	(146)
Reconciliation to rate level	261	245	(216)
Total credit recognized	$ (354)	$ 89	$ 89