Leases - Future Minimum Lease Payments (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Operating Leases
2021	$ 80
2022	76
2023	73
2024	73
2025	74
All years thereafter	993
Total future minimum lease payments	1,369
Less: imputed interest	(475)
Total	894
Operating lease liabilities (current)	83	$ 65
Operating lease liabilities (noncurrent)	811	809
Total	894
Finance Leases
2021	1
2022	1
2023	0
2024	0
2025	0
All years thereafter	1
Total future minimum lease payments	3
Less: imputed interest	0
Other noncurrent liabilities	2
Other current liabilities	1
Total	3
CECONY
Operating Leases
2021	60
2022	57
2023	56
2024	56
2025	57
All years thereafter	504
Total future minimum lease payments	790
Less: imputed interest	(167)
Total	623
Operating lease liabilities (current)	64	54
Operating lease liabilities (noncurrent)	559	$ 551
Total	623
Finance Leases
2021	1
2022	1
2023	0
2024	0
2025	0
All years thereafter	0
Total future minimum lease payments	2
Less: imputed interest	0
Other noncurrent liabilities	1
Other current liabilities	1
Total	$ 2