Commitments and Contingencies - Narrative (Details) $ in Millions		6 Months Ended	12 Months Ended
	Mar. 23, 2016 USD ($) MW	Jun. 30, 2019 USD ($) MGPSite Open_claim MW	Dec. 31, 2022 MW	Dec. 31, 2018 USD ($) MW	Dec. 31, 2017 MW
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		$ 3,211
Accrual for Environmental Loss Contingencies, Gross		482		$ 496
Exelon Generation Co L L C [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		2,554
Accrued Insurance, Current		13,900
Loss Contingency, Undiscounted Amount of Insurance-related Assessment Liability		450
Maximum liability per nuclear incident		13,500
Prepaid Reinsurance Premiums		334
Estimated Insurance Recoveries		3,200
Accrual for Environmental Loss Contingencies, Gross		107		108
Liability for Asbestos and Environmental Claims, Gross		84		79
Commonwealth Edison Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		$ 259
Mgp Site Contingency Approved Cleanup Count | MGPSite		42
Mgp Site Contingency Count | MGPSite		21
Mgp Site Contingency Monitoring Count | MGPSite		21
Accrual for Environmental Loss Contingencies, Gross		$ 318		329
PECO Energy Co [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		$ 187
Mgp Site Contingency Approved Cleanup Count | MGPSite		26
Mgp Site Contingency Count | MGPSite		17
Mgp Site Contingency Monitoring Count | MGPSite		9
Accrual for Environmental Loss Contingencies, Gross		$ 25		27
Baltimore Gas and Electric Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		$ 26
Mgp Site Contingency Approved Cleanup Count | MGPSite		13
Mgp Site Contingency Count | MGPSite		9
Mgp Site Contingency Monitoring Count | MGPSite		4
Accrual for Environmental Loss Contingencies, Gross		$ 5		5
Pepco Holdings LLC [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		75
Accrual for Environmental Loss Contingencies, Gross		27		27
Potomac Electric Power Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		50
Accrual for Environmental Loss Contingencies, Gross		24		25
Delmarva Power and Light Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		$ 15
Mgp Site Contingency Approved Cleanup Count | MGPSite		3
Mgp Site Contingency Count | MGPSite		2
Accrual for Environmental Loss Contingencies, Gross		$ 1		$ 1
Open Claims [Member] | Exelon Generation Co L L C [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Liability for Asbestos and Environmental Claims, Gross		$ 24
Open Asbestos Related Personal Injury Claims | Open_claim		244
Estimated Future Claims [Member] | Exelon Generation Co L L C [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Liability for Asbestos and Environmental Claims, Gross		$ 60
Nuclear Insurance Premiums [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Nuclear financial protection pool value		2,900
Nuclear Insurance Premiums [Member] | Maximum [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Nuclear financial protection pool value		434
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
West Lake [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross		280
West Lake [Member] | Exelon Generation Co L L C [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Accrual for Environmental Loss Contingencies, Gross		20
Accrual for Environmental Loss Contingencies, Component Amount		$ 90
Other Solar Projects [Member] | Pepco Holdings Inc [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Business Acquisition, Expected New Generation Mwh | MW	37
Other Non-Financial Commitment | MW		27
Other Commitment	$ 127	$ 102
Other Solar Projects [Member] | Pepco Holdings Inc [Member] | Exelon Generation Co L L C [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Commitment		$ 102
Wind Assets [Member] | Pepco Holdings Inc [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Other Non-Financial Commitment | MW	100
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
Subsequent Event [Member] | Wind Assets [Member] | Pepco Holdings Inc [Member] | Delmarva Power and Light Company [Member]
Commitments And Contingencies Additional Narrative Information [Line Items]
Purchase Commitment | MW			40