Securitization Activities - Additional Information (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Assets securitized in a non-cash exchange for loans and investments | $ 551 | $ 601 | $ 882 |
| Net Asset related to Other Continuing Involvement | 52 | 57 | |
| Notional amount related to Other Continuing Involvement | 1,430 | 1,200 | |
| Fair Value of Retained Interests | 3,190 | 3,350 | |
| Other Retained Interests [Member] | |||
| Fair Value of Retained Interests | $ 192 | $ 149 | |
| Weighted average life (years) | 3 years 10 months 24 days | 3 years 3 months 18 days | |
| Maximum Exposure to Adverse Changes in the value of Other retained interests | $ 192 | $ 149 | |