Commitments and Contingencies - Narrative (Details) $ in Millions		1 Months Ended	12 Months Ended
	Mar. 23, 2016 MW	Nov. 30, 2020 USD ($)	Dec. 31, 2022 MW	Dec. 31, 2018 MW	Dec. 31, 2017 MW	Jun. 30, 2022 USD ($) MGPSite	Dec. 31, 2021 USD ($)
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						$ 610
Accrual for Environmental Loss Contingencies, Gross						347	$ 352
Commonwealth Edison Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						$ 226
Mgp Site Contingency Monitoring Count | MGPSite						21
Accrual for Environmental Loss Contingencies, Gross						$ 274	279
Deferred Prosecution Agreement Payments		$ 200
Customer Refund Liability, Noncurrent						38
PECO Energy Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						$ 182
Mgp Site Contingency Monitoring Count | MGPSite						6
Accrual for Environmental Loss Contingencies, Gross						$ 21	22
Baltimore Gas and Electric Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						$ 4
Mgp Site Contingency Monitoring Count | MGPSite						4
Accrual for Environmental Loss Contingencies, Gross						$ 7	6
Pepco Holdings LLC [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						125
Accrual for Environmental Loss Contingencies, Gross						42	42
Potomac Electric Power Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						94
Accrual for Environmental Loss Contingencies, Gross						40	40
Delmarva Power and Light Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						$ 20
Mgp Site Contingency Count | MGPSite						1
Accrual for Environmental Loss Contingencies, Gross						$ 1	$ 1
Pepco Holdings Inc [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						513
Pepco Holdings Inc [Member] | Pepco Holdings LLC [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						320
Pepco Holdings Inc [Member] | Potomac Electric Power Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						120
Pepco Holdings Inc [Member] | Delmarva Power and Light Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment						$ 89
Wind Assets [Member] | Pepco Holdings Inc [Member] | Delmarva Power and Light Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Purchase Commitment | MW	120			40	40
Wind Assets [Member] | Pepco Holdings Inc [Member] | Delmarva Power and Light Company [Member] | Forecast [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Purchase Commitment | MW			40