Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 46	$ 41	$ 89	$ 80
Interest cost on projected benefit obligation	162	162	321	324
Expected return on plan assets	(282)	(279)	(564)	(557)
Recognition of net actuarial loss (gain)	1	(58)	(3)	(115)
Recognition of prior service credit	(4)	(4)	(9)	(9)
TOTAL PERIODIC BENEFIT CREDIT	(77)	(138)	(166)	(277)
Cost capitalized	(23)	(21)	(46)	(42)
Reconciliation to rate level	8	74	27	147
Total credit recognized	(92)	(85)	(185)	(172)
CECONY | Subsidiaries
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	43	38	84	75
Interest cost on projected benefit obligation	152	153	302	305
Expected return on plan assets	(268)	(265)	(538)	(530)
Recognition of net actuarial loss (gain)	1	(55)	(4)	(109)
Recognition of prior service credit	(5)	(5)	(10)	(10)
TOTAL PERIODIC BENEFIT CREDIT	(77)	(134)	(166)	(269)
Cost capitalized	(22)	(20)	(43)	(39)
Reconciliation to rate level	5	68	21	135
Total credit recognized	$ (94)	$ (86)	$ (188)	$ (173)