Derivatives and Hedging Activities - Derivatives with Credit-Related Contingent Features (Detail) - USD ($) $ in Millions |
Sep. 30, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Derivative [Line Items] | ||
| Aggregate fair value of derivative contracts which are in net liability position | $ 36,431 | $ 43,368 |
| Aggregate fair value of assets as a collateral for derivative contracts | 30,647 | 35,296 |
| One-Notch Reduction [Member] | ||
| Derivative [Line Items] | ||
| Additional collateral or termination payments pursuant to bilateral agreements with certain counterparties which could have been called by counterparties in the event of a reduction in the firm's long-term credit ratings | 331 | 481 |
| Two-Notch Reduction [Member] | ||
| Derivative [Line Items] | ||
| Additional collateral or termination payments pursuant to bilateral agreements with certain counterparties which could have been called by counterparties in the event of a reduction in the firm's long-term credit ratings | $ 1,353 | $ 1,388 |