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Regulatory Matters - Capitalized Ratemaking Amount Not Recognized (Details) - USD ($) $ in Millions | Sep. 30, 2024 | Dec. 31, 2023
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Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | $ 126 | $ 110
Commonwealth Edison Co |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | 43 | 32
PECO Energy Co |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | 0 | 0
Baltimore Gas and Electric Company |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | 22 | 33
Pepco Holdings LLC |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | 61 | 45
Potomac Electric Power Company |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | 47 | 34
Delmarva Power and Light Company |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | 1 | 1
Atlantic City Electric Company |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes | $ 13 | $ 10

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- Definition Discloses the amount of any allowance for earnings on shareholders' investment capitalized for rate making purposes but not for the financial statements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478742/980-340-50-3 + Details
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