Financial Instruments and Risk Management - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2020	Sep. 30, 2019
Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation	$ 26.3	$ (28.1)
Exit lease liability	0.0	(0.1)
Net Liabilities at estimated fair value	(40.4)	(25.1)
Foreign currency contracts | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - Foreign Currency contracts	(0.5)	4.3
Foreign currency contracts | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - Foreign Currency contracts	(1.2)	4.5
Foreign currency contracts | Level 2 | Fair Value, Measurements, Recurring | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - Foreign Currency contracts	(0.5)	4.3
Derivatives - 2017 and 2018 Interest Rate swaps | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - Foreign Currency contracts	(8.9)	(4.7)
Commodity contract | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - Foreign Currency contracts	(3.5)	(1.0)
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Fair Value Amount	$ 2,722.3	$ 2,474.7