Trading Cash Instruments - Additional Information (Detail) - Trading Cash Instruments Assets Fair Value Disclosure [Member] - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
|
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Net gains / (losses) on assets | $ 132 | $ (77) |
| Net realized gains / (losses) on assets | 80 | 66 |
| Net unrealized gains / (losses) on assets relating to instruments still held at the reporting date | 52 | (143) |
| Market making [Member] | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Net gains / (losses) on assets | 45 | (193) |
| Interest Income [Member] | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Net gains / (losses) on assets | $ 87 | $ 116 |