Basis of Presentation and Major Accounting Policies (Allowance for Doubtful Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Allowance for Credit Losses
Beginning balance	$ 25.1	$ 23.9	$ 24.8
Adoption of new credit losses standard		0.5
Provision for credit losses	7.5	2.7	7.7
Write-offs charged against the allowance	(7.9)	(3.8)	(8.3)
Currency translation and other	(0.6)	1.8	(0.3)
Ending balance	$ 24.1	$ 25.1	$ 23.9