Revenues (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2026 |
Mar. 31, 2025 |
Sep. 30, 2025 |
|
| Revenue from Contract with Customer [Abstract] | |||||
| Customer rebate liability | $ 126.2 | $ 126.2 | $ 113.7 | ||
| Rebates recorded | $ 156.8 | $ 143.2 | $ 316.7 | $ 293.3 | |