Commitments and Contingencies - Merger Commitment (Details) $ in Millions	Sep. 30, 2023 USD ($)
Other Commitments [Line Items]
Other Commitment	$ 634
Pepco Holdings LLC
Other Commitments [Line Items]
Other Commitment	126
Potomac Electric Power Company
Other Commitments [Line Items]
Other Commitment	95
Delmarva Power and Light Company
Other Commitments [Line Items]
Other Commitment	19
Atlantic City Electric Company
Other Commitments [Line Items]
Other Commitment	12
Pepco Holdings Inc [Member]
Other Commitments [Line Items]
Other Commitment	513
Pepco Holdings Inc [Member] | Remaining commitment
Other Commitments [Line Items]
Other Commitment	42
Pepco Holdings Inc [Member] | Pepco Holdings LLC
Other Commitments [Line Items]
Other Commitment	320
Pepco Holdings Inc [Member] | Pepco Holdings LLC | Remaining commitment
Other Commitments [Line Items]
Other Commitment	39
Pepco Holdings Inc [Member] | Potomac Electric Power Company
Other Commitments [Line Items]
Other Commitment	120
Pepco Holdings Inc [Member] | Potomac Electric Power Company | Remaining commitment
Other Commitments [Line Items]
Other Commitment	34
Pepco Holdings Inc [Member] | Delmarva Power and Light Company
Other Commitments [Line Items]
Other Commitment	89
Pepco Holdings Inc [Member] | Delmarva Power and Light Company | Remaining commitment
Other Commitments [Line Items]
Other Commitment	3
Pepco Holdings Inc [Member] | Atlantic City Electric Company
Other Commitments [Line Items]
Other Commitment	111
Pepco Holdings Inc [Member] | Atlantic City Electric Company | Remaining commitment
Other Commitments [Line Items]
Other Commitment	$ 2