Commitments and Contingencies - Merger Commitment (Details) $ in Millions	Sep. 30, 2026 USD ($)
Other Commitments [Line Items]
Other Commitment	$ 930
Pepco Holdings LLC
Other Commitments [Line Items]
Other Commitment	188
Potomac Electric Power Company
Other Commitments [Line Items]
Other Commitment	155
Delmarva Power and Light Company
Other Commitments [Line Items]
Other Commitment	18
Atlantic City Electric Company
Other Commitments [Line Items]
Other Commitment	15
Pepco Holdings Inc [Member]
Other Commitments [Line Items]
Other Commitment	513
Pepco Holdings Inc [Member] \| Remaining commitment
Other Commitments [Line Items]
Other Commitment	20
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	18
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	18
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	0
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	$ 0