Debt and Other Financing Activities - Summary of Cash Flow Activity Related to Accounts Receivable Sales Programs (Details) - USD ($) $ in Millions |
9 Months Ended | |
|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| U.S. Accounts Receivable Sales Program [Member] | ||
| Disclosure Of Sales Program Of Receivable [Line Items] | ||
| Gross proceeds received | $ 100 | $ 290 |
| Cash collections | 91 | 301 |
| Net change in receivables sales volume | 9 | (11) |
| Foreign Accounts Receivable Sales Program [Member] | ||
| Disclosure Of Sales Program Of Receivable [Line Items] | ||
| Gross proceeds received | 57 | 413 |
| Cash collections | 45 | 400 |
| Net change in receivables sales volume | $ 12 | $ 13 |