Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Site Contingency [Line Items]
Accrued liabilities	$ 1,027	$ 1,037
Regulatory assets	5,631	5,664
Manufactured gas plant sites
Site Contingency [Line Items]
Accrued liabilities	937	941
Other Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	90	96
Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	1,027	1,037
Regulatory assets	1,031	1,038
CECONY
Site Contingency [Line Items]
Accrued liabilities	933	942
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	5,258	5,264
CECONY | Manufactured gas plant sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	843	846
CECONY | Other Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	90	96
CECONY | Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	933	942
Regulatory assets	$ 944	$ 952