Description of Business and Basis of Presentation - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Hedging settlement gains	$ (1.1)	$ 3.8	$ (4.4)	$ 6.3
Accounting Standards Update 2017-02 | Scenario, Adjustment | Other Items, Net
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Hedging settlement gains			(4.8)
Accounting Standards Update 2017-02 | Scenario, Adjustment | Cost of Products Sold
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Hedging settlement gains			$ (4.8)