Income Taxes - Components of income tax provision (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Taxes [Abstract]
Federal	$ 61.1	$ 141.0	$ 92.6
State	4.5	14.6	8.5
Foreign	14.2	23.5	14.1
Total current	79.8	179.1	115.2
Federal	0.6	(36.6)	(16.8)
State	0.6	(1.8)	(0.8)
Foreign	(7.6)	(11.1)	(4.5)
Total deferred	(6.4)	(49.5)	(22.1)
Total income tax provision	$ 73.4	$ 129.6	$ 93.1