Accounts Receivable - Purchases and Sales of Accounts Receivable (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	$ 2,333	$ 2,054
Commonwealth Edison Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	571	464
PECO Energy Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	707	598
Baltimore Gas and Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	325	375
Pepco Holdings LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	730	617
Potomac Electric Power Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	472	383
Delmarva Power and Light Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	132	126
Atlantic City Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	$ 126	$ 108