Environmental Matters - Accrued Liability (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Site Contingency [Line Items]
Regulatory assets	$ 5,789	$ 5,664
Regulatory liabilities	5,210	5,546
Asbestos Suits
Site Contingency [Line Items]
Accrued liability	8	8
Regulatory assets	8	8
Workers’ Compensation
Site Contingency [Line Items]
Accrued liability	54	53
Regulatory liabilities	18	20
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	5,400	5,264
Regulatory liabilities	4,661	4,980
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	52	51
Regulatory liabilities	$ 18	$ 20