Securitization Activities - Amount of Financial Assets Securitized and Cash Flows Received on Retained Interests (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Transfers and Servicing of Financial Assets [Abstract] | |||
| Securitization of residential mortgages | $ 20,167 | $ 15,124 | $ 21,229 |
| Securitization of commercial mortgages | 14,904 | 12,741 | 8,745 |
| Securitization of other financial assets | 1,775 | 1,252 | 1,914 |
| Total financial assets securitized | 36,846 | 29,117 | 31,888 |
| Retained interests cash flows | $ 331 | $ 286 | $ 296 |