Other Postretirement Benefits - Schedule of Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	$ 524
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	583	$ 524
CECONY
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	502
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	560	502
Other Postretirement Benefits
CHANGE IN BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	963	1,058	$ 1,398
Service cost	13	14	18
Interest cost on accumulated other postretirement benefit obligation	47	57	35
Net actuarial gain	(57)	(93)	(311)
Benefits paid and administrative expenses, net of subsidies	(120)	(128)	(130)
Participant contributions	52	55	48
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	898	963	1,058
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	929	860	1,150
Actual return on plan assets	56	116	(225)
Employer contributions	13	22	13
Employer group waiver plan subsidies	66	56	55
Participant contributions	52	55	48
Benefits paid	(182)	(180)	(181)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	934	929	860
FUNDED STATUS	36	(34)	(198)
Unrecognized net loss/(gain)	(119)	(90)	37
Unrecognized prior service costs	(9)	(10)	(12)
Other Postretirement Benefits | CECONY
CHANGE IN BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	825	921	1,189
Service cost	10	12	15
Interest cost on accumulated other postretirement benefit obligation	40	49	30
Net actuarial gain	(38)	(94)	(239)
Benefits paid and administrative expenses, net of subsidies	(112)	(118)	(121)
Participant contributions	50	55	47
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	775	825	921
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	750	708	955
Actual return on plan assets	44	84	(187)
Employer contributions	10	17	10
Employer group waiver plan subsidies	60	52	50
Participant contributions	50	55	47
Benefits paid	(170)	(166)	(167)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	744	750	708
FUNDED STATUS	(31)	(75)	(213)
Unrecognized net loss/(gain)	(57)	(41)	78
Unrecognized prior service costs	$ 0	$ 0	$ 0