Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Site Contingency [Line Items]
Accrued liabilities	$ 1,032	$ 1,037
Regulatory assets	5,789	5,664
Manufactured gas plant sites
Site Contingency [Line Items]
Accrued liabilities	941	941
Other Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	91	96
Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	1,032	1,037
Regulatory assets	1,037	1,038
CECONY
Site Contingency [Line Items]
Accrued liabilities	937	942
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	5,400	5,264
CECONY | Manufactured gas plant sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	846	846
CECONY | Other Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	91	96
CECONY | Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	937	942
Regulatory assets	$ 951	$ 952