Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Sep. 30, 2024 |
Sep. 30, 2023 |
Sep. 30, 2022 |
|
| Allowance for credit losses | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | $ 19 | $ 19 | $ 20 |
| Additions Charged to Cost and Expenses | 10 | 5 | 5 |
| Deductions | (3) | (5) | (6) |
| Balance at End of period | 26 | 19 | 19 |
| Reserves for sales returns | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | 19 | 19 | 23 |
| Additions Charged to Cost and Expenses | 37 | 39 | 52 |
| Deductions | (36) | (39) | (56) |
| Balance at End of period | 20 | 19 | 19 |
| Allowance for deferred tax asset | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Period | 25 | 29 | 38 |
| Additions Charged to Cost and Expenses | 1 | 1 | 2 |
| Deductions | (1) | (5) | (11) |
| Balance at End of period | $ 25 | $ 25 | $ 29 |