CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 6.2	$ 69.5
Other comprehensive income (loss), net of tax:
Employee pension and postretirement benefits	8.6	1.2
Currency translation adjustments	(6.9)	31.8
Change in fair value of derivative instruments	0.7	(0.1)
Total other comprehensive income (loss), net of tax	2.4	32.9
Comprehensive income	$ 8.6	$ 102.4