Environmental Matters - Accrued Liability (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Site Contingency [Line Items]
Regulatory assets	$ 5,260	$ 4,888
Asbestos Suits
Site Contingency [Line Items]
Accrued liability	8	8
Regulatory assets	8	8
Workers’ Compensation
Site Contingency [Line Items]
Accrued liability	57	56
Regulatory assets	15	17
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	4,948	4,568
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	55	54
Regulatory assets	$ 15	$ 17