Accounts Receivable - Unbilled Customer Revenue (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 812	$ 991
Commonwealth Edison Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	338	351
PECO Energy Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	149	185
Baltimore Gas and Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	135	208
Pepco Holdings LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	190	247
Potomac Electric Power Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	83	109
Delmarva Power and Light Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	46	64
Atlantic City Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 61	$ 74