Derivative Financial Instruments - Summary of Counterparty Collateral (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	$ 516	$ 557
External Counterparties | Commodity Contract [Member] | Collateral [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	156	148
External Counterparties | Commodity Contract [Member] | Collateral [Member] | Commonwealth Edison Co
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	154	146
External Counterparties | Commodity Contract [Member] | Collateral [Member] | PECO Energy Co
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	0	0
External Counterparties | Commodity Contract [Member] | Collateral [Member] | Baltimore Gas and Electric Company
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	1	1
External Counterparties | Commodity Contract [Member] | Collateral [Member] | Pepco Holdings LLC
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	1	1
External Counterparties | Commodity Contract [Member] | Collateral [Member] | Potomac Electric Power Company
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	0	1
External Counterparties | Commodity Contract [Member] | Collateral [Member] | Delmarva Power and Light Company
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	1	0
External Counterparties | Commodity Contract [Member] | Collateral [Member] | Atlantic City Electric Company
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Other	$ 1	$ 0