Financial Instruments Financial Instruments (Effects of Derivatives Not Designated as a Hedging Instrument) (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Other Income (Expense), Net
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	$ 2.8	$ (1.5)
Other Income (Expense), Net | Forward Exchange Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	2.8	(1.5)
Other Income (Expense), Net | Other
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	0.0	0.0
Other Non-Operating Income (Expense), Net
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	(2.2)	1.8
Other Non-Operating Income (Expense), Net | Forward Exchange Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	(2.7)	1.1
Other Non-Operating Income (Expense), Net | Other
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	$ 0.5	$ 0.7