INCOME TAXES - Schedule of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
United States	$ 8.0	$ (399.8)	$ (263.0)
Outside the United States	155.6	109.6	172.7
Income (loss) from continuing operations before income taxes	$ 163.6	$ (290.2)	$ (90.3)