Environmental Matters - Accrued Liabilities and Regulatory Assets (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Site Contingency [Line Items]
Accrued liabilities	$ 1,113	$ 1,118
Regulatory assets	5,263	4,888
Manufactured gas plant sites
Site Contingency [Line Items]
Accrued liabilities	1,005	1,016
Other Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	108	102
Superfund Sites
Site Contingency [Line Items]
Accrued liabilities	1,113	1,118
Regulatory assets	1,100	1,105
CECONY
Site Contingency [Line Items]
Accrued liabilities	1,020	1,026
CECONY | Subsidiaries
Site Contingency [Line Items]
Regulatory assets	4,922	4,568
CECONY | Manufactured gas plant sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	913	924
CECONY | Other Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	107	102
CECONY | Superfund Sites | Subsidiaries
Site Contingency [Line Items]
Accrued liabilities	1,020	1,026
Regulatory assets	$ 1,017	$ 1,022