Summary of Significant Accounting Policies and Other Matters - Capitalized Cost of Utility Plant (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Public Utility, Property, Plant and Equipment [Line Items]
General	$ 4,851	$ 4,835
Held for future use	77	118
Construction work in progress	3,165	2,442
NET UTILITY PLANT	52,152	49,594
Electric Generation
Public Utility, Property, Plant and Equipment [Line Items]
Generation	577	580
Electric Transmission
Public Utility, Property, Plant and Equipment [Line Items]
Transmission	5,072	4,652
Electric Distribution
Public Utility, Property, Plant and Equipment [Line Items]
Distribution	25,129	24,491
General
Public Utility, Property, Plant and Equipment [Line Items]
General	174	141
Gas
Public Utility, Property, Plant and Equipment [Line Items]
Gas	12,703	12,023
Steam
Public Utility, Property, Plant and Equipment [Line Items]
Steam	2,006	1,990
General
Public Utility, Property, Plant and Equipment [Line Items]
General	3,249	3,158
CECONY
Public Utility, Property, Plant and Equipment [Line Items]
General	4,520	4,530
Held for future use	69	110
Construction work in progress	2,912	2,168
NET UTILITY PLANT	48,981	46,646
CECONY | Electric Generation
Public Utility, Property, Plant and Equipment [Line Items]
Generation	577	580
CECONY | Electric Transmission
Public Utility, Property, Plant and Equipment [Line Items]
Transmission	4,703	4,333
CECONY | Electric Distribution
Public Utility, Property, Plant and Equipment [Line Items]
Distribution	23,770	23,238
CECONY | General
Public Utility, Property, Plant and Equipment [Line Items]
General	174	141
CECONY | Gas
Public Utility, Property, Plant and Equipment [Line Items]
Gas	11,830	11,226
CECONY | Steam
Public Utility, Property, Plant and Equipment [Line Items]
Steam	2,006	1,990
CECONY | General
Public Utility, Property, Plant and Equipment [Line Items]
General	$ 2,940	$ 2,860