Regulatory Matters - Annual Electric Transmission Fillings (Details) - Subsequent Event [Member] $ in Millions	Apr. 24, 2024 USD ($)
Commonwealth Edison Co \| 2024 Transmission Formula Rate Annual Update
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 32
Annual Reconciliation Increase	(12)
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 20
Public Utilities, Approved Equity Capital Structure, Percentage	8.14%
Public Utilities, Approved Return on Equity, Percentage	11.50%
Basis points for Transmission Formula Rate	50
Baltimore Gas and Electric Company \| 2024 Transmission Formula Rate Annual Update
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 42
Annual Reconciliation Increase	13
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 53
Public Utilities, Approved Equity Capital Structure, Percentage	7.47%
Public Utilities, Approved Return on Equity, Percentage	10.50%
Basis points for Transmission Formula Rate	50
Baltimore Gas and Electric Company \| 2024 Transmission Formula Rate Revenue Reduction
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 2

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