Pension Benefits - Schedule of Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	$ 459
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	524	$ 459
Pension Benefits
CHANGE IN PROJECTED BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	12,113	17,357	$ 18,965
Service cost – excluding administrative expenses	156	283	337
Interest cost on projected benefit obligation	649	505	471
Net actuarial loss/(gain)	599	(5,102)	(1,547)
Plan amendments	3	0	0
Benefits paid	(808)	(930)	(869)
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	12,712	12,113	17,357
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	14,979	18,504	17,022
Actual return on plan assets	1,261	(2,583)	1,935
Employer contributions	21	30	469
Benefits paid	(808)	(930)	(869)
Administrative expenses	(49)	(42)	(53)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	15,404	14,979	18,504
FUNDED STATUS	2,692	2,866	1,147
Unrecognized net loss/(gain)	(757)	(1,485)	205
Unrecognized prior service credits	(105)	(124)	(140)
Accumulated benefit obligation	11,739	11,167	15,469
CECONY
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	439
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	502	439
CECONY | Pension Benefits
CHANGE IN PROJECTED BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	11,395	16,341	17,821
Service cost – excluding administrative expenses	146	266	317
Interest cost on projected benefit obligation	611	475	443
Net actuarial loss/(gain)	572	(4,845)	(1,441)
Plan amendments	0	0	0
Benefits paid	(747)	(842)	(799)
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	11,977	11,395	16,341
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	14,248	17,566	16,147
Actual return on plan assets	1,201	(2,453)	1,838
Employer contributions	18	17	432
Benefits paid	(747)	(842)	(799)
Administrative expenses	(46)	(40)	(52)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	14,674	14,248	17,566
FUNDED STATUS	2,697	2,853	1,225
Unrecognized net loss/(gain)	(705)	(1,397)	207
Unrecognized prior service credits	(124)	(143)	(163)
Accumulated benefit obligation	$ 11,031	$ 10,478	$ 14,504