INCOME TAXES - Reconciliation of the Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Sep. 30, 2022 |
Sep. 30, 2021 |
Sep. 30, 2020 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Balance at beginning of year | $ 24.1 | $ 30.2 | $ 29.5 |
| Additions for tax positions of the current year | 11.3 | 0.3 | 0.3 |
| Additions for tax positions of prior years | 2.2 | 6.1 | 4.5 |
| Reductions for tax positions of prior years | (2.5) | (5.9) | (2.4) |
| Settlements with tax authorities | 1.3 | 0.2 | 0.3 |
| Expiration of statutes of limitation | (0.6) | (6.8) | (2.0) |
| Balance at end of year | $ 35.8 | $ 24.1 | $ 30.2 |