Accounts Receivable - Unbilled Customer Revenue (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 709	$ 912
Commonwealth Edison Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	237	223
PECO Energy Co [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	149	219
Baltimore Gas and Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	149	247
Pepco Holdings LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	174	223
Potomac Electric Power Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	74	103
Delmarva Power and Light Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	49	74
Atlantic City Electric Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 51	$ 46