COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025
Accumulated Other Comprehensive Income (Loss)
Beginning balance	$ 2,978.5	$ 2,077.1	$ 2,952.4	$ 2,134.3
Other comprehensive income (loss)	(15.8)	38.2	(3.9)	(0.8)
Ending balance	2,981.2	2,140.3	2,981.2	2,140.3
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(238.9)	(385.8)	(250.8)	(347.6)
Other comprehensive income (loss)			(3.4)	(0.5)
Ending balance	(254.2)	(348.1)	(254.2)	(348.1)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss)
Beginning balance			(201.1)	(265.9)
Other comprehensive income (loss)			(4.6)	(32.9)
Ending balance	(205.7)	(298.8)	(205.7)	(298.8)
Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss)
Beginning balance			8.1	(5.0)
Other comprehensive income (loss)			(0.9)	30.3
Ending balance	7.2	25.3	7.2	25.3
Minimum Pension Liability Adjustment
Accumulated Other Comprehensive Income (Loss)
Beginning balance			(57.8)	(76.7)
Other comprehensive income (loss)			2.1	2.1
Ending balance	$ (55.7)	$ (74.6)	$ (55.7)	$ (74.6)