Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 42	$ 43
Interest cost on projected benefit obligation	168	159
Expected return on plan assets	(279)	(282)
Recognition of net actuarial gain	(66)	(4)
Recognition of prior service credit	(4)	(4)
TOTAL PERIODIC BENEFIT CREDIT	(139)	(88)
Cost capitalized	(21)	(22)
Reconciliation to rate level	(16)	18
Total credit recognized	(176)	(92)
CECONY | Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	39	40
Interest cost on projected benefit obligation	159	150
Expected return on plan assets	(266)	(269)
Recognition of net actuarial gain	(63)	(4)
Recognition of prior service credit	(5)	(5)
TOTAL PERIODIC BENEFIT CREDIT	(136)	(88)
Cost capitalized	(20)	(22)
Reconciliation to rate level	(16)	16
Total credit recognized	$ (172)	$ (94)