Supplemental Financial Statement Information (Supplemental Statement of Income Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Financial Statement Related Disclosures [Line Items]
Interest income	$ (5.6)	$ (0.2)
Foreign currency exchange gain (loss)	23.7	(1.0)
Pension cost other than service costs	1.0	0.7
Transition services agreement income	(1.0)	0.0
Other	0.9	(0.9)
Total Other items, net	19.0	$ (1.4)
ARGENTINA
Financial Statement Related Disclosures [Line Items]
Foreign currency exchange gain (loss)	$ 21.0