Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 43	$ 41
Interest cost on projected benefit obligation	159	162
Expected return on plan assets	(282)	(279)
Recognition of net actuarial gain	(4)	(58)
Recognition of prior service credit	(4)	(4)
TOTAL PERIODIC BENEFIT CREDIT	(88)	(138)
Cost capitalized	(22)	(21)
Reconciliation to rate level	18	73
Total credit recognized	(92)	(86)
CECONY | Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	40	38
Interest cost on projected benefit obligation	150	153
Expected return on plan assets	(269)	(265)
Recognition of net actuarial gain	(4)	(55)
Recognition of prior service credit	(5)	(5)
TOTAL PERIODIC BENEFIT CREDIT	(88)	(134)
Cost capitalized	(22)	(20)
Reconciliation to rate level	16	68
Total credit recognized	$ (94)	$ (86)