Summary of Significant Accounting Policies and Other Matters - Plant and Depreciation Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Public Utility, Property, Plant and Equipment [Line Items]
Annual aggregate depreciation allowance	$ 2,228
Software Licenses
Public Utility, Property, Plant and Equipment [Line Items]
Gross asset	59	$ 65
Estimated aggregate annual amortization expense	7
Accumulated amortization	$ 45	$ 38
Non-Utility Plant | Maximum | Solar Powered Generating Assets
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	35 years
Non-Utility Plant | Maximum | Wind Power Generating Assets
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	30 years
Non-Utility Plant | Maximum | Land And Conduit
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	10 years
CECONY
Public Utility, Property, Plant and Equipment [Line Items]
AFUDC rates (percent)	5.90%	5.90%	5.20%
Average depreciation rates (percent)	3.60%	3.60%	3.50%
Annual aggregate depreciation allowance	$ 2,109
CECONY | Software Licenses
Public Utility, Property, Plant and Equipment [Line Items]
Gross asset	56	$ 62
Estimated aggregate annual amortization expense	7
Accumulated amortization	$ 43	$ 36
CECONY | Electric | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | Electric | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	80 years
CECONY | Gas | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | Gas | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	80 years
CECONY | Steam | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | Steam | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	55 years
CECONY | General Plant | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
CECONY | General Plant | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	50 years
O&R
Public Utility, Property, Plant and Equipment [Line Items]
AFUDC rates (percent)	6.00%	6.20%	5.00%
Average depreciation rates (percent)	3.30%	3.10%	3.00%
O&R | Electric | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
O&R | Electric | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	75 years
O&R | General Plant | Minimum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	5 years
O&R | General Plant | Maximum
Public Utility, Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	50 years