Accumulated Other Comprehensive Loss (Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2023	Sep. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		$ (216.1)	$ (136.9)
OCI before reclassifications	[1]	44.7	(77.5)
Reclassification to earnings		1.4	1.7
Ending Balance		(170.0)	(216.1)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(131.2)	(41.8)
OCI before reclassifications	[1]	44.3	(89.4)
Reclassification to earnings		0.0	0.0
Ending Balance		(86.9)	(131.2)
Pension and Post-retirement Activity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(92.6)	(97.3)
OCI before reclassifications	[1]	(0.3)	(1.2)
Reclassification to earnings		6.9	5.9
Ending Balance		(86.0)	(92.6)
Hedging Activity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		7.7	2.2
OCI before reclassifications	[1]	0.7	13.1
Reclassification to earnings		(5.5)	(7.6)
Ending Balance		$ 2.9	$ 7.7

[1] OCI is defined as other comprehensive income.