Leases - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($) lease_agreement	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) lease_agreement	Sep. 30, 2024 USD ($)
Lessee, Lease, Description [Line Items]
Unrecorded unconditional purchase obligation	$ 443,000,000		$ 443,000,000
Right-of-use assets		$ 0	11,000,000
Termination cost	0		$ 0
CECONY
Lessee, Lease, Description [Line Items]
Right-of-use assets	$ 2,000,000			$ 0
CECONY | Subsidiaries
Lessee, Lease, Description [Line Items]
Number of operating lease agreements | lease_agreement	4		4
CECONY | Subsidiaries | Lease Expected To Commence In 3 Years With 15 Year Lease Term
Lessee, Lease, Description [Line Items]
Operating lease, not yet commenced, term of contract (in years)	15 years		15 years