Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Assets under finance leases	$ 2		$ 2		$ 2
Finance leases, accumulated amortization	2		2		5
Right-of-use assets	9	$ 5	11	$ 76
CECONY
Lessee, Lease, Description [Line Items]
Assets under finance leases	1		1		1
Finance leases, accumulated amortization	1		1		$ 2
CECONY | Subsidiaries
Lessee, Lease, Description [Line Items]
Right-of-use assets	$ 9	$ 3	$ 11	$ 67