Environmental Matters - Schedule of Accrued Liability for Asbestos Suits and Workers' Compensation Proceedings (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Site Contingency [Line Items]
Regulatory assets	$ 5,702	$ 5,664
Regulatory liabilities	5,623	5,546
Asbestos Suits
Site Contingency [Line Items]
Accrued liability	11	8
Regulatory assets	11	8
Workers' Compensation
Site Contingency [Line Items]
Accrued liability	51	53
Regulatory liabilities	$ 21	$ 20
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities:	Accrued Liabilities:
CECONY | Asbestos Suits
Site Contingency [Line Items]
Accrued liability	$ 10	$ 7
Regulatory assets	10	7
CECONY | Workers' Compensation
Site Contingency [Line Items]
Accrued liability	49	51
Regulatory liabilities	$ 21	$ 20
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities:	Accrued Liabilities: