Accounts Receivable - Purchases and Sales of Accounts Receivable (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	$ 2,054	$ 1,961
Commonwealth Edison Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	464	450
PECO Energy Co
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	598	527
Baltimore Gas and Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	375	393
Pepco Holdings LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	617	591
Potomac Electric Power Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	383	375
Delmarva Power and Light Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	126	115
Atlantic City Electric Company
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, Purchase	$ 108	$ 101