Commitments and Contingencies - Schedule of Environmental Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	$ 428	$ 409
Commonwealth Edison Co
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	303	325
PECO Energy Co
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	27	25
Baltimore Gas and Electric Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	14	9
Pepco Holdings LLC
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	81	46
Potomac Electric Power Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	79	44
Delmarva Power & Light Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	1	1
Atlantic City Electric Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	1	1
Accrual For MGP Investigation And Remediation [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	338	355
Accrual For MGP Investigation And Remediation [Member] | Commonwealth Edison Co
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	302	324
Accrual For MGP Investigation And Remediation [Member] | PECO Energy Co
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	25	23
Accrual For MGP Investigation And Remediation [Member] | Baltimore Gas and Electric Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	11	8
Accrual For MGP Investigation And Remediation [Member] | Pepco Holdings LLC
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	0	0
Accrual For MGP Investigation And Remediation [Member] | Potomac Electric Power Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	0	0
Accrual For MGP Investigation And Remediation [Member] | Delmarva Power & Light Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	0	0
Accrual For MGP Investigation And Remediation [Member] | Atlantic City Electric Company
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross	$ 0	$ 0