Property, Equipment and Technology, Net - Schedule of Property, Equipment and Technology, Net (Details) - USD ($) $ in Millions |
Sep. 30, 2025 |
Sep. 30, 2024 |
|---|---|---|
| Property, Plant and Equipment [Line Items] | ||
| Total property, equipment and technology | $ 10,106 | $ 9,297 |
| Accumulated depreciation and amortization | (5,870) | (5,473) |
| Property, equipment and technology, net | 4,236 | 3,824 |
| Land | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property, equipment and technology | 72 | 72 |
| Buildings and building improvements | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property, equipment and technology | 1,004 | 1,042 |
| Furniture, equipment and leasehold improvements | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property, equipment and technology | 2,240 | 2,301 |
| Technology | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property, equipment and technology | 6,599 | 5,660 |
| Assets not yet placed in service | ||
| Property, Plant and Equipment [Line Items] | ||
| Total property, equipment and technology | $ 191 | $ 222 |