Product Warranty Obligations (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Changes in the product warranty obligations
Balance at beginning of period	$ 38.5	$ 37.3
Accruals for warranties issued during the current period	27.2	27.3
Adjustments to pre-existing warranties	0.6	(3.0)
Settlements of warranty claims	(24.2)	(24.2)
Balance at end of period	$ 42.1	$ 37.4