Leases - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Lease, renewal term (in years)	5 years
Assets under finance leases	$ 3	$ 3	$ 2
Finance leases, accumulated amortization	3	2	2
Finance lease costs and cash flows	0	0	0
Right-of-use asset obtained in exchange for operating lease liability	46	3
Unrecorded unconditional purchase obligation	442
CECONY
Lessee, Lease, Description [Line Items]
Assets under finance leases	2	3	1
Finance leases, accumulated amortization	3	2	2
Finance lease costs and cash flows	0	0	$ 0
Right-of-use asset obtained in exchange for operating lease liability	$ 45	$ 3
CECONY | Subsidiaries | Lease Expected To Commence In 3 Years With 15 Year Lease Term
Lessee, Lease, Description [Line Items]
Lease not yet commenced, term (in years)	15 years
Operating lease, lease not yet commenced, expected period to commence (in years)	3 years
Minimum
Lessee, Lease, Description [Line Items]
Lease, term (in years)	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lease, term (in years)	20 years