Derivative Financial Instruments - Summary of Counterparty Collateral (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Other current liabilities	$ 968	$ 1,155
Commonwealth Edison Co
Derivative [Line Items]
Other current liabilities	219	191
PECO Energy Co
Derivative [Line Items]
Other current liabilities	59	32
Baltimore Gas and Electric Company
Derivative [Line Items]
Other current liabilities	34	55
Potomac Electric Power Company
Derivative [Line Items]
Other current liabilities	61	93
Delmarva Power & Light Company
Derivative [Line Items]
Other current liabilities	21	136
Atlantic City Electric Company
Derivative [Line Items]
Other current liabilities	12	58
External Counterparties | Commodity Contract | Collateral
Derivative [Line Items]
Other current liabilities	148	297
External Counterparties | Commodity Contract | Collateral | Commonwealth Edison Co
Derivative [Line Items]
Other current liabilities	146	77
External Counterparties | Commodity Contract | Collateral | PECO Energy Co
Derivative [Line Items]
Other current liabilities	0	0
External Counterparties | Commodity Contract | Collateral | Baltimore Gas and Electric Company
Derivative [Line Items]
Other current liabilities	1	23
External Counterparties | Commodity Contract | Collateral | Pepco Holdings LLC
Derivative [Line Items]
Other current liabilities	1	197
External Counterparties | Commodity Contract | Collateral | Potomac Electric Power Company
Derivative [Line Items]
Other current liabilities	1	26
External Counterparties | Commodity Contract | Collateral | Delmarva Power & Light Company
Derivative [Line Items]
Other current liabilities	0	121
External Counterparties | Commodity Contract | Collateral | Atlantic City Electric Company
Derivative [Line Items]
Other current liabilities	$ 0	$ 50