Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 41	$ 72	$ 80	$ 144
Interest cost on projected benefit obligation	162	126	324	252
Expected return on plan assets	(279)	(292)	(557)	(585)
Recognition of net actuarial loss/(gain)	(58)	94	(115)	189
Recognition of prior service credit	(4)	(4)	(9)	(8)
TOTAL PERIODIC BENEFIT CREDIT	(138)	(4)	(277)	(8)
Cost capitalized	(21)	(35)	(42)	(68)
Reconciliation to rate level	74	66	147	130
Total credit recognized	(85)	27	(172)	54
CECONY | Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	38	67	75	135
Interest cost on projected benefit obligation	153	119	305	237
Expected return on plan assets	(265)	(277)	(530)	(554)
Recognition of net actuarial loss/(gain)	(55)	89	(109)	179
Recognition of prior service credit	(5)	(5)	(10)	(10)
TOTAL PERIODIC BENEFIT CREDIT	(134)	(7)	(269)	(13)
Cost capitalized	(20)	(33)	(39)	(65)
Reconciliation to rate level	68	62	135	123
Total credit recognized	$ (86)	$ 22	$ (173)	$ 45