Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Lease, renewal term	5 years
Assets under finance leases	$ 2	$ 3
Finance leases, accumulated amortization	4	3
Right-of-use asset obtained in exchange for operating lease liability	$ 58	23
Lease not yet commenced, term	45 years
Lease not yet commenced, present value of lease payments	$ 6
CECONY
Lessee, Lease, Description [Line Items]
Assets under finance leases	1	2
Finance leases, accumulated amortization	2	1
Right-of-use asset obtained in exchange for operating lease liability	$ 12	$ 11
Minimum
Lessee, Lease, Description [Line Items]
Lease, term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lease, term	40 years