Pension Benefits - Schedule of Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 45	$ 42
Interest cost on projected benefit obligation	167	168
Expected return on plan assets	(262)	(279)
Recognition of net actuarial gain	(22)	(66)
Recognition of prior service credit	(4)	(4)
TOTAL PERIODIC BENEFIT CREDIT	(76)	(139)
Cost capitalized	(25)	(21)
Reconciliation to rate level	(41)	(16)
Total credit recognized	(142)	(176)
CECONY | Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	43	39
Interest cost on projected benefit obligation	158	159
Expected return on plan assets	(251)	(266)
Recognition of net actuarial gain	(22)	(63)
Recognition of prior service credit	(5)	(5)
TOTAL PERIODIC BENEFIT CREDIT	(77)	(136)
Cost capitalized	(24)	(20)
Reconciliation to rate level	(40)	(16)
Total credit recognized	$ (141)	$ (172)