Leases - Future Minimum Lease Payments (Details) $ in Millions	Jun. 30, 2019 USD ($)
Operating Leases
2020	$ 77
2021	74
2022	70
2023	68
2024	68
All years thereafter	970
Total future minimum lease payments	1,327
Less: imputed interest	(451)
Total	876
Operating lease liabilities (current)	55
Operating lease liabilities (noncurrent)	821
Total	876
Finance Leases
2020	1
2021	0
2022	0
2023	0
2024	0
All years thereafter	1
Total future minimum lease payments	2
Less: imputed interest	0
Total	2
Other current liabilities	1
Other noncurrent liabilities	1
Total	2
CECONY
Operating Leases
2020	58
2021	57
2022	54
2023	53
2024	53
All years thereafter	551
Total future minimum lease payments	826
Less: imputed interest	(185)
Total	641
Operating lease liabilities (current)	46
Operating lease liabilities (noncurrent)	595
Total	641
Finance Leases
2020	1
2021	0
2022	0
2023	0
2024	0
All years thereafter	0
Total future minimum lease payments	1
Less: imputed interest	0
Total	1
Other current liabilities	1
Other noncurrent liabilities	0
Total	$ 1