Pension Benefits - Schedule of Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	$ 465
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	525	$ 465
Pension Benefits
CHANGE IN PROJECTED BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	18,965	16,792	$ 14,449
Service cost – excluding administrative expenses	337	288	245
Interest cost on projected benefit obligation	471	549	601
Net actuarial loss/(gain)	(1,547)	2,281	2,191
Plan amendments	0	0	15
Benefits paid	(869)	(945)	(709)
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	17,357	18,965	16,792
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	17,022	15,608	13,450
Actual return on plan assets	1,935	1,927	2,556
Employer contributions	469	475	350
Benefits paid	(869)	(945)	(709)
Administrative expenses	(53)	(43)	(39)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	18,504	17,022	15,608
FUNDED STATUS	1,147	(1,943)	(1,184)
Unrecognized net loss	205	3,330	2,604
Unrecognized prior service costs/(credits)	(140)	(156)	(173)
Accumulated benefit obligation	15,469	16,768	15,015
CECONY
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	439
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	499	439
CECONY | Pension Benefits
CHANGE IN PROJECTED BENEFIT OBLIGATION
Projected benefit obligation at beginning of year	17,821	15,750	13,542
Service cost – excluding administrative expenses	317	269	228
Interest cost on projected benefit obligation	443	515	564
Net actuarial loss/(gain)	(1,441)	2,154	2,076
Plan amendments	0	0	0
Benefits paid	(799)	(867)	(660)
PROJECTED BENEFIT OBLIGATION AT END OF YEAR	16,341	17,821	15,750
CHANGE IN PLAN ASSETS
Fair value of plan assets at beginning of year	16,147	14,790	12,744
Actual return on plan assets	1,838	1,830	2,425
Employer contributions	432	435	318
Benefits paid	(799)	(867)	(660)
Administrative expenses	(52)	(41)	(37)
FAIR VALUE OF PLAN ASSETS AT END OF YEAR	17,566	16,147	14,790
FUNDED STATUS	1,225	(1,674)	(960)
Unrecognized net loss	207	3,145	2,466
Unrecognized prior service costs/(credits)	(163)	(183)	(202)
Accumulated benefit obligation	$ 14,504	$ 15,676	$ 14,010