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, 2020	Sep. 30, 2019
Other Income (Expense), Net
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	$ (1.5)	$ (0.7)
Other Income (Expense), Net | Forward Exchange Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	(1.5)	1.3
Other Income (Expense), Net | Other
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	0.0	(2.0)
Other Nonoperating Income (Expense), Net
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	1.8	0.0
Other Nonoperating Income (Expense), Net | Forward Exchange Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	1.1	0.0
Other Nonoperating Income (Expense), Net | Other
Derivative Instruments, Gain (Loss) [Line Items]
Total (Gain) Loss Recognized in Income	$ 0.7	$ 0.0