Unsecured Borrowings - Unsecured Long-Term Borrowings after Hedging (Detail) - USD ($) $ in Millions |
Sep. 30, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Debt Instrument [Line Items] | ||
| Fixed-rate obligations: At fair value | $ 3,188 | $ 1,521 |
| Fixed rate obligations at amortized cost | 30,180 | 30,827 |
| Floating-rate obligations: At fair value | 44,692 | 39,390 |
| Floating rate obligations at amortized cost | 164,720 | 141,743 |
| Total | $ 242,780 | $ 213,481 |