Summary of Significant Accounting Policies (Schedule of Product Warranty Liability) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Accounting Policies [Abstract]
Balance at end of year	$ 14.4	$ 17.1	$ 20.0	$ 8.5
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of year	6.5
Product Warranty Expense	2.6	3.9	18.7
Warranty payments	(5.3)	(6.8)	$ (7.2)
Balance at end of year	$ 7.2	$ 6.5