Summary of Significant Accounting Policies and Other Matters - Capitalized Cost of Utility Plant (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Public Utility, Property, Plant and Equipment [Line Items]
General	$ 4,835	$ 4,205
Held for future use	118	117
Construction work in progress	2,442	2,484
NET UTILITY PLANT	49,594	46,752
Electric Generation
Public Utility, Property, Plant and Equipment [Line Items]
Generation	580	534
Electric Transmission
Public Utility, Property, Plant and Equipment [Line Items]
Transmission	4,652	4,223
Electric Distribution
Public Utility, Property, Plant and Equipment [Line Items]
Distribution	24,491	23,345
General
Public Utility, Property, Plant and Equipment [Line Items]
General	141	113
Gas
Public Utility, Property, Plant and Equipment [Line Items]
Gas	12,023	11,326
Steam
Public Utility, Property, Plant and Equipment [Line Items]
Steam	1,990	1,962
General
Public Utility, Property, Plant and Equipment [Line Items]
General	3,158	2,648
CECONY
Public Utility, Property, Plant and Equipment [Line Items]
General	4,530	3,879
Held for future use	110	109
Construction work in progress	2,168	2,268
NET UTILITY PLANT	46,646	44,009
CECONY | Electric Generation
Public Utility, Property, Plant and Equipment [Line Items]
Generation	580	534
CECONY | Electric Transmission
Public Utility, Property, Plant and Equipment [Line Items]
Transmission	4,333	3,916
CECONY | Electric Distribution
Public Utility, Property, Plant and Equipment [Line Items]
Distribution	23,238	22,130
CECONY | General
Public Utility, Property, Plant and Equipment [Line Items]
General	141	113
CECONY | Gas
Public Utility, Property, Plant and Equipment [Line Items]
Gas	11,226	10,567
CECONY | Steam
Public Utility, Property, Plant and Equipment [Line Items]
Steam	1,990	1,962
CECONY | General
Public Utility, Property, Plant and Equipment [Line Items]
General	$ 2,860	$ 2,410