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, 2021 |
Sep. 30, 2020 |
Sep. 30, 2021 |
Sep. 30, 2020 |
|
| Transfers and Servicing of Financial Assets [Abstract] | ||||
| Securitization of residential mortgages | $ 9,888 | $ 7,717 | $ 19,894 | $ 15,725 |
| Securitization of commercial mortgages | 3,066 | 6,279 | 13,832 | 14,062 |
| Securitization of other financial assets | 2,353 | 66 | 4,017 | 1,189 |
| Total financial assets securitized | 15,307 | 14,062 | 37,743 | 30,976 |
| Retained interests cash flows | $ 204 | $ 130 | $ 452 | $ 274 |