Other (Expense) Income (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Components of other (expense) income
Net gain (loss) on disposition of property	$ 0.1	$ (0.6)	$ (0.5)
Interest income	10.7	9.5	9.8
Royalty income	2.9	2.5	3.3
Legacy product liability and environmental charges	(19.8)	(14.6)	(24.9)
Other	0.6	12.9	18.0
Other (expense) income	$ (5.5)	9.7	5.7
Gain from favorable resolutions of certain intellectual property and commercial legal matters		$ 8.0	$ 19.2