Accounts Receivable - Unbilled Customer Revenue (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 740	$ 912
Commonwealth Edison Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	279	223
PECO Energy Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	135	219
Baltimore Gas and Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	118	247
Pepco Holdings LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	208	223
Potomac Electric Power Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	100	103
Delmarva Power and Light Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	44	74
Atlantic City Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled customer revenue	$ 64	$ 46