Guarantees (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 27.5	$ 32.1
Provision for warranties during the period	2.6	6.0
Warranty claims during the period	(3.8)	(5.4)
Balance at end of period	$ 26.3	$ 32.7