Financial Instruments and Risk Management (Schedule of Gains and Losses on Derivative Instruments) (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Derivative Instruments, Gain (Loss) [Line Items]
OCI gain (loss) on cash flow hedge, reclassification before tax		$ 3.0	$ 5.9	$ 8.0
FX contract | Designated as hedging instrument | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	[1]	4.0	(0.8)	1.1
FX contract | Not designated as hedging instrument
Derivative Instruments, Gain (Loss) [Line Items]
Change in estimate of fair value of foreign currency contracts		$ 0.6	$ 0.4	$ 3.0

[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.