Accounts Receivable - Unbilled Customer Revenue (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 849	$ 991
Commonwealth Edison Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	344	351
PECO Energy Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	138	185
Baltimore Gas and Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	171	208
Pepco Holdings LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	196	247
Potomac Electric Power Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	96	109
Delmarva Power and Light Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	53	64
Atlantic City Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 47	$ 74