Leases - Lease Cost and Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 67	$ 70	$ 88
Operating lease cash flows	67	68	83
CECONY
Lessee, Lease, Description [Line Items]
Operating lease cost	66	66	67
Operating lease cash flows	$ 66	$ 65	$ 64