Collateralized Agreements and Financings - Resale and Repurchase Agreements and Securities Borrowed and Loaned Transactions (Parenthetical) (Detail) - USD ($) $ in Millions |
Jun. 30, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Collateralized Agreements And Financings [Abstract] | ||
| Securities borrowed at fair value | $ 41,076 | $ 28,898 |
| Securities loaned at fair value | $ 6,301 | $ 1,053 |