Fair Value Measurements - Schedule of Commodity Derivatives (Details) - Level 3 $ in Millions	Dec. 31, 2022 USD ($) $ / MWh $ / kW-month
CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	$ (6)
Electricity - Held and Used | Forward Capacity Prices
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	(15)
Electricity - Held and Used | Forward Capacity Prices | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	$ (7)
Electricity - Held and Used | Forward Capacity Prices | Minimum | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	1.42
Electricity - Held and Used | Forward Capacity Prices | Maximum | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	16.08
Transmission Congestion Contracts/Financial Transmission Rights - Held and Used | Inter-Zonal Forward Price Curves
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	$ 1
Transmission Congestion Contracts/Financial Transmission Rights - Held and Used | Inter-Zonal Forward Price Curves | Minimum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	0.91
Transmission Congestion Contracts/Financial Transmission Rights - Held and Used | Inter-Zonal Forward Price Curves | Maximum
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	3.03
Total Con Edison - Commodity - Held and Used
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	$ (14)
Electricity - Held for Sale | Forward Energy Prices
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	14
Electricity - Held for Sale | Forward Capacity Prices
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	10
Transmission Congestion Contracts/Financial Transmission Rights - Held for Sale | Inter-Zonal Forward Price Curves
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	4
Natural Gas - Held for Sale | Forward Natural Gas Price
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	1
Commodity Contract, Held For Sale
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	29
Commodity Contract
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	15
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives	$ 1
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Minimum | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	0.91
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Maximum | CECONY
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	3.03