Regulatory Matters - Capitalized Ratemaking Amounts Not Recognized (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	$ 117	$ 110
Commonwealth Edison Co
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	46	32
PECO Energy Co
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	0	0
Baltimore Gas and Electric Company
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	16	33
Pepco Holdings LLC
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	55	45
Potomac Electric Power Company
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	40	34
Delmarva Power & Light Company
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	1	1
Atlantic City Electric Company
Public Utilities, General Disclosures [Line Items]
Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes	$ 14	$ 10