Environmental Matters - Accrued Liability (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Regulatory assets	$ 4,414	$ 4,279
Asbestos Suits
Site Contingency [Line Items]
Accrued liability	8	8
Regulatory assets	8	8
Workers’ Compensation
Site Contingency [Line Items]
Accrued liability	60	61
Regulatory assets	13	11
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	4,117	3,955
CECONY | Asbestos Suits | Subsidiaries
Site Contingency [Line Items]
Accrued liability	7	7
Regulatory assets	7	7
CECONY | Workers’ Compensation | Subsidiaries
Site Contingency [Line Items]
Accrued liability	57	59
Regulatory assets	$ 13	$ 11