Commitments and Contingencies - Narrative (Details) $ in Millions		1 Months Ended	3 Months Ended			12 Months Ended
	Mar. 23, 2016 MW	Nov. 30, 2020 USD ($)	Sep. 30, 2022 USD ($) MGPSite	Mar. 31, 2019 MW	Mar. 31, 2018 MW	Dec. 31, 2022 MW	Dec. 31, 2021 USD ($)
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment			$ 630
Accrual for Environmental Loss Contingencies, Gross			405				$ 352
Commonwealth Edison Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment			$ 256
Mgp Site Contingency Monitoring Count | MGPSite			20
Accrual for Environmental Loss Contingencies, Gross			$ 328				279
Deferred Prosecution Agreement Payments		$ 200
Customer Refund Liability, Current			38
Commonwealth Edison Co [Member] | Illinois Chamber of Commerce
Commitments And Contingencies Additional Narrative Information [Line Items]
Customer Refund Liability, Current			31
PECO Energy Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment			$ 181
Mgp Site Contingency Monitoring Count | MGPSite			6
Accrual for Environmental Loss Contingencies, Gross			$ 25				22
Baltimore Gas and Electric Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment			$ 5
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			126
Accrual for Environmental Loss Contingencies, Gross			41				42
Potomac Electric Power Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment			95
Accrual for Environmental Loss Contingencies, Gross			39				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
Accrual For MGP Investigation And Remediation [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross			358				303
Accrual For MGP Investigation And Remediation [Member] | Commonwealth Edison Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross			328				279
Accrual for Environmental Loss Contingencies, Period Increase (Decrease)			60
Accrual For MGP Investigation And Remediation [Member] | PECO Energy Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross			24				20
Accrual For MGP Investigation And Remediation [Member] | Baltimore Gas and Electric Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross			6				4
Accrual For MGP Investigation And Remediation [Member] | Pepco Holdings LLC [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross			0				0
Accrual For MGP Investigation And Remediation [Member] | Potomac Electric Power Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross			0				0
Accrual For MGP Investigation And Remediation [Member] | Delmarva Power and Light Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross			$ 0				$ 0
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