Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Accrued liabilities	$ 994	$ 997
Regulatory assets	4,601	4,279
Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	900	903
Manufactured gas plant sites
Site Contingency [Line Items]
Accrued liabilities	874	876
Other Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	120	121
Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	994	997
Regulatory assets	986	991
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	4,278	3,955
CECONY | Manufactured gas plant sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	780	782
CECONY | Other Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	120	121
CECONY | Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	900	903
Regulatory assets	$ 902	$ 906