Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Accrued liabilities	$ 994	$ 997
Regulatory assets	4,414	4,279
Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	900	903
Manufactured gas plant sites
Site Contingency [Line Items]
Accrued liabilities	872	876
Other Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	122	121
Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	994	997
Regulatory assets	985	991
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	4,117	3,955
CECONY | Manufactured gas plant sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	778	782
CECONY | Other Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	122	121
CECONY | Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	900	903
Regulatory assets	$ 900	$ 906