Financial Instruments and Risk Management (Schedule of Gains and Losses on Derivative Instruments) (Details) - FX contract - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2024		Sep. 30, 2023	Sep. 30, 2022
Designated as hedging instrument | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in OCI	[1]	$ (0.8)		$ 1.1	$ 19.2
Gain (loss) reclassified from AOCI into income (effective portion)		$ 5.9		$ 8.0	$ 11.2
Gain (loss) reclassified from AOCI into income - financial statement location	[1],[2]	Nonoperating Income (Expense)		Nonoperating Income (Expense)	Nonoperating Income (Expense)
Not designated as hedging instrument
Derivative Instruments, Gain (Loss) [Line Items]
Change in estimate of fair value of foreign currency contracts		$ 0.4
Gain (loss) on fair value hedges - financial statement location		Nonoperating Income (Expense)	[2]		Nonoperating Income (Expense)

[1] Each of these derivative instruments had a high correlation to the underlying exposure being hedged for the periods indicated and had been deemed highly effective in offsetting associated risk.

[2] ain (loss) was recorded in Other expense (income), net.