Pension Benefits - Total Periodic Benefit Costs (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	$ 343	$ 293	$ 250
Interest cost on projected benefit obligation	471	549	601
Expected return on plan assets	(1,096)	(1,034)	(988)
Recognition of net actuarial loss	787	699	518
Recognition of prior service credit	(17)	(16)	(17)
TOTAL PERIODIC BENEFIT COST	488	491	364
Cost capitalized	(154)	(130)	(108)
Reconciliation to rate level	(226)	(250)	(15)
Total credit recognized	108	111	241
CECONY
Defined Benefit Plan Disclosure [Line Items]
Service cost – including administrative expenses	321	274	232
Interest cost on projected benefit obligation	443	515	564
Expected return on plan assets	(1,040)	(980)	(936)
Recognition of net actuarial loss	746	661	492
Recognition of prior service credit	(19)	(19)	(19)
TOTAL PERIODIC BENEFIT COST	451	451	333
Cost capitalized	(146)	(123)	(102)
Reconciliation to rate level	(216)	(239)	(12)
Total credit recognized	$ 89	$ 89	$ 219