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Regulatory Matters - Energy Efficiency Formula Rate (Details) - Commonwealth Edison Co $ in Millions |  |  | 9 Months Ended
--- | --- | --- | ---
May 30, 2024 USD ($) | Feb. 03, 2022 | Sep. 30, 2023
Schedule of Energy Efficiency Formula Rate Updates [Line Items] |  |  |
Basis points for ComEd's Revenue Requirement |  | 580 |
ComEd 2024 Energy Efficiency Formula Rate |  |  |
Schedule of Energy Efficiency Formula Rate Updates [Line Items] |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount | $ 66 |  |
Public Utilities Requested Rate Increase (Decrease), Prior Year Annual Reconciliation | (8) |  |
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount | $ 58 |  |
Public Utilities, Requested Equity Capital Structure, Percentage | 7.02% |  |
Requested Return on Equity, Percentage | 9.89% |  |
ComEd 2024 Energy Efficiency Formula Rate | 2024 |  |  |
Schedule of Energy Efficiency Formula Rate Updates [Line Items] |  |  |
Basis points for ComEd's Revenue Requirement | 580 |  |
ComEd 2023 Energy Efficiency Formula Rate |  |  |
Schedule of Energy Efficiency Formula Rate Updates [Line Items] |  |  |
Public Utilities, Approved Equity Capital Structure, Percentage |  |  | 7.25%
Public Utilities, Approved Return on Equity, Percentage |  |  | 10.34%

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- Definition Maximum basis points that can be added to the average rate on 30-year treasury notes, to determine the allowed ROE for ComEd's revenue requirement. + References No definition available. + Details
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