Basis of Presentation and Major Accounting Policies (Allowance for Doubtful Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Allowance for Credit Losses
Beginning balance	$ 22.9	$ 24.1	$ 25.1
Provision for credit losses	10.7	8.2	7.5
Write-offs charged against the allowance	(8.5)	(7.9)	(7.9)
Currency translation and other	1.2	(1.5)	(0.6)
Ending balance	$ 26.3	$ 22.9	$ 24.1