Leases - Lease Cost and Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 86	$ 85
Operating lease cash flows	80	79
CECONY
Lessee, Lease, Description [Line Items]
Operating lease cost	66	65
Operating lease cash flows	$ 63	$ 61