Leases - Future Minimum Lease Payments (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Operating Leases
2022	$ 81
2023	77
2024	77
2025	78
2026	76
All years thereafter	877
Total future minimum lease payments	1,266
Less: imputed interest	(436)
Total	830
Operating lease liabilities (current)	113	$ 96
Operating lease liabilities (noncurrent)	717	$ 764
Total	830
Finance Leases
2022	0
2023	0
2024	1
2025	0
2026	0
All years thereafter	1
Total future minimum lease payments	2
Less: imputed interest	0
Total	2
Other current liabilities	0
Other noncurrent liabilities	2
Total	$ 2
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Liabilities, Current	Liabilities, Current
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Liabilities, Other than Long-term Debt, Noncurrent	Liabilities, Other than Long-term Debt, Noncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Liabilities, Other than Long-term Debt, Noncurrent, Other Liabilities	Liabilities, Other than Long-term Debt, Noncurrent, Other Liabilities
CECONY
Operating Leases
2022	$ 60
2023	59
2024	59
2025	60
2026	59
All years thereafter	394
Total future minimum lease payments	691
Less: imputed interest	(139)
Total	552
Operating lease liabilities (current)	90	$ 73
Operating lease liabilities (noncurrent)	462	$ 512
Total	552
Finance Leases
2022	0
2023	0
2024	1
2025	0
2026	0
All years thereafter	0
Total future minimum lease payments	1
Less: imputed interest	0
Total	1
Other current liabilities	0
Other noncurrent liabilities	1
Total	$ 1