Fair Value Measurements - Schedule of Commodity Derivatives (Details) - Level 3 $ in Millions	Dec. 31, 2025 USD ($) $ / MWh $ / kW-month
Electricity | Forward Capacity Prices | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ (5)
Electricity | Forward Capacity Prices | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ (3)
Electricity | Forward Capacity Prices | Minimum | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	1.36
Electricity | Forward Capacity Prices | Minimum | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	1.36
Electricity | Forward Capacity Prices | Maximum | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	13.76
Electricity | Forward Capacity Prices | Maximum | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	13.76
Electricity | Forward Capacity Prices | Weighted Average | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	4.33
Electricity | Forward Capacity Prices | Weighted Average | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / kW-month	4.72
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ 0
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ 0
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Minimum | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	(2.04)
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Minimum | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	(2.04)
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Maximum | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	3.03
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Maximum | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	3.03
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Weighted Average | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	1.15
Transmission Congestion Contracts | Inter-Zonal Forward Price Curves | Weighted Average | CECONY | Subsidiaries | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unobservable Inputs Range (dollar per unit) | $ / MWh	1.15
Commodity | Discounted Cash Flow
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ (5)
Commodity | CECONY | Subsidiaries
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value of commodity derivatives | $	$ (3)