Environmental Matters - Accrued Liability for Asbestos Suits and Workers' Compensation Proceedings (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Regulatory assets	$ 4,888	$ 4,279
Regulatory liabilities	5,473	6,401
Asbestos Suits
Site Contingency [Line Items]
Accrued liability	8	8
Regulatory assets	8	8
Workers' Compensation
Site Contingency [Line Items]
Accrued liability	56	61
Regulatory liabilities	$ 17	$ 11
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities	Accrued Liabilities
CECONY | Asbestos Suits
Site Contingency [Line Items]
Accrued liability	$ 7	$ 7
Regulatory assets	7	7
CECONY | Workers' Compensation
Site Contingency [Line Items]
Accrued liability	54	59
Regulatory liabilities	$ 17	$ 11
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]	Accrued Liabilities	Accrued Liabilities