Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 44	$ 40	$ 133	$ 122
Interest cost on projected benefit obligation	160	162	481	486
Expected return on plan assets	(282)	(279)	(846)	(837)
Recognition of net actuarial gain	(1)	(58)	(4)	(174)
Recognition of prior service credit	(4)	(4)	(13)	(12)
TOTAL PERIODIC BENEFIT CREDIT	(83)	(139)	(249)	(415)
Cost capitalized	(22)	(19)	(68)	(61)
Reconciliation to rate level	12	72	39	218
Total credit recognized	(93)	(86)	(278)	(258)
CECONY | Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	42	38	126	113
Interest cost on projected benefit obligation	151	153	453	458
Expected return on plan assets	(269)	(265)	(807)	(795)
Recognition of net actuarial gain	(2)	(55)	(5)	(164)
Recognition of prior service credit	(5)	(5)	(15)	(15)
TOTAL PERIODIC BENEFIT CREDIT	(83)	(134)	(248)	(403)
Cost capitalized	(21)	(18)	(65)	(58)
Reconciliation to rate level	10	66	31	202
Total credit recognized	$ (94)	$ (86)	$ (282)	$ (259)