Leases - Future Minimum Lease Payments (Details) $ in Millions	Dec. 31, 2019 USD ($)
Operating Leases
2020	$ 78
2021	75
2022	73
2023	72
2024	72
All years thereafter	992
Total future minimum lease payments	1,362
Less: imputed interest	(488)
Total	874
Operating lease liabilities (current)	65
Operating lease liabilities (noncurrent)	809
Total	874
Finance Leases
2020	0
2021	0
2022	0
2023	0
2024	0
All years thereafter	1
Total future minimum lease payments	1
Less: imputed interest	0
Total	1
Other noncurrent liabilities	1
Total	1
CECONY
Operating Leases
2020	60
2021	57
2022	55
2023	54
2024	55
All years thereafter	501
Total future minimum lease payments	782
Less: imputed interest	(177)
Total	605
Operating lease liabilities (current)	54
Operating lease liabilities (noncurrent)	551
Total	605
Finance Leases
2020	0
2021	0
2022	0
2023	0
2024	0
All years thereafter	0
Total future minimum lease payments	0
Less: imputed interest	0
Total	0
Other noncurrent liabilities	0
Total	$ 0