Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Site Contingency [Line Items]
Accrued liabilities	$ 927	$ 940
Regulatory assets	3,880	3,845
Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	837	850
Manufactured gas plant sites
Site Contingency [Line Items]
Accrued liabilities	835	845
Other Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	92	95
Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	927	940
Regulatory assets	926	938
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	3,541	3,504
CECONY | Manufactured gas plant sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	745	755
CECONY | Other Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	92	95
CECONY | Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	837	850
Regulatory assets	$ 847	$ 860