Environmental Matters - Accrued Liability (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Site Contingency [Line Items]
Regulatory assets	$ 3,880	$ 3,845
Asbestos Suits
Site Contingency [Line Items]
Accrued liability	8	8
Regulatory assets	8	8
Workers’ Compensation
Site Contingency [Line Items]
Accrued liability	63	65
Regulatory assets	10	8
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	3,541	3,504
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	60	62
Regulatory assets	$ 10	$ 8