Accounts Receivable - Purchases and Sales of Accounts Receivable (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Mar. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cash proceeds received						$ 400
Loss on sale of receivables	$ 14	$ 8	$ 24	$ 25
Proceeds from new transfers			3,393	2,689
Cash collections received on DPP and reinvested in the Facility			1,595	1,809
Cash collections reinvested in the Facility			4,988	4,498
Total receivables sold			96	107
Exelon Utility Registrants Affiliates
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables sold to Exelon's utility subsidiaries prior to the separation on February 1, 2022			4	15
Sale of Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Derecognized receivables transferred at fair value	1,505		1,505		$ 1,265
Cash proceeds received	900		900		900
DPP	$ 605		605		$ 365
Customer accounts receivable sold into the Facility			$ 5,253	$ 4,647