Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 72	$ 85	$ 144	$ 171
Interest cost on projected benefit obligation	126	118	252	236
Expected return on plan assets	(292)	(274)	(585)	(548)
Recognition of net actuarial loss	94	197	189	393
Recognition of prior service credit	(4)	(4)	(8)	(8)
TOTAL PERIODIC BENEFIT COST/(CREDIT)	(4)	122	(8)	244
Cost capitalized	(35)	(41)	(68)	(79)
Reconciliation to rate level	66	(54)	130	(111)
Total credit recognized	27	27	54	54
CECONY | Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	67	80	135	160
Interest cost on projected benefit obligation	119	111	237	222
Expected return on plan assets	(277)	(260)	(554)	(520)
Recognition of net actuarial loss	89	187	179	373
Recognition of prior service credit	(5)	(5)	(10)	(10)
TOTAL PERIODIC BENEFIT COST/(CREDIT)	(7)	113	(13)	225
Cost capitalized	(33)	(39)	(65)	(75)
Reconciliation to rate level	62	(52)	123	(106)
Total credit recognized	$ 22	$ 22	$ 45	$ 44