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Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Nov. 30, 2020	Sep. 30, 2024
Commonwealth Edison Co
Commitments And Contingencies Additional Narrative Information [Line Items]
Mgp Site Contingency Monitoring Count		16
Deferred Prosecution Agreement Payments	$ 200.0
Loss Contingency Accrual		$ 46.2
Customer Refund Liability, Current		38.0
Commonwealth Edison Co | Accrual For MGP Investigation And Remediation
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Period Increase (Decrease)		13.0
Commonwealth Edison Co | Illinois Chamber of Commerce
Commitments And Contingencies Additional Narrative Information [Line Items]
Customer Refund Liability, Current		$ 31.0
PECO Energy Co
Commitments And Contingencies Additional Narrative Information [Line Items]
Mgp Site Contingency Monitoring Count		6
PECO Energy Co | Accrual For MGP Investigation And Remediation
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Period Increase (Decrease)		$ 4.0
Baltimore Gas and Electric Company
Commitments And Contingencies Additional Narrative Information [Line Items]
Mgp Site Contingency Monitoring Count		4
Delmarva Power and Light Company
Commitments And Contingencies Additional Narrative Information [Line Items]
Mgp Site Contingency Monitoring Count		1
Potomac Electric Power Company
Commitments And Contingencies Additional Narrative Information [Line Items]
Environmental Liability - Anacostia		$ 47.0
Environmental Liability - Buzzard Point		10.0
Exelon Business Services Co Affiliate
Commitments And Contingencies Additional Narrative Information [Line Items]
Deferred Prosecution Agreement Liability, Current		173.0
Insurers' Settlement Payment		40.0
Settling Shareholders' Attorney Fees		$ 10.0

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
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-Name Accounting Standards Codification
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Amount of loss contingency liability.

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Name of the individual site or other grouping of the contingency.

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