Basis of Presentation and Accounting Policies - Supply Chain Financing Program, Outstanding Obligations (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Supplier Finance Program, Obligation [Roll Forward] | ||
| Balance at the beginning of the year | $ 68 | $ 77 |
| Invoices confirmed during the period | 254 | 237 |
| Payments made during the period | (236) | (246) |
| Balance at the end of the year | $ 86 | $ 68 |
| Supplier finance program, obligation, current, statement of financial position [Extensible Enumeration] | Accounts Payable, Current | |