Securitization Activities - Amount of Financial Assets Securitized and Cash Flows Received on Retained Interests (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Transfers and Servicing [Abstract]
Residential mortgages	$ 6,894	$ 6,128	$ 18,267	$ 25,069
Commercial mortgages	1,798	2,306	3,196	13,820
Other financial assets	0	902	996	3,519
Total financial assets securitized	8,692	9,336	22,459	42,408
Retained interests cash flows	$ 187	$ 125	$ 407	$ 428