Settlement Guarantee Management - Collateral (Detail) - USD ($) $ in Millions |
Mar. 31, 2023 |
Sep. 30, 2022 |
|---|---|---|
| Settlement Guarantee Management [Abstract] | ||
| Restricted cash and restricted cash equivalents | $ 2,739 | $ 2,342 |
| Pledged securities at market value | 294 | 213 |
| Letters of credit | 1,638 | 1,582 |
| Guarantees | 1,068 | 950 |
| Total | $ 5,739 | $ 5,087 |