Summary of Significant Accounting Policies Revenue Recognition - Impact on Income Statement (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Jun. 30, 2019		Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 446.6	[1]	$ 446.0	[1]	$ 1,321.5	$ 1,295.4
Cost of Goods and Services Sold	298.2		282.5		865.2	817.1
Gross profit	148.4		163.5		456.3	478.3
Operating expenses	90.8		98.3		275.2	285.7
Income before income taxes	43.3		51.4		140.1	86.5
Income tax expense	11.6		15.2		39.9	52.5
Consolidated net income	31.7		$ 36.2		100.2	$ 34.0
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	1.0				(0.1)
Cost of Goods and Services Sold	1.0				0.0
Gross profit	0.0				(0.1)
Income before income taxes	0.0				(0.1)
Consolidated net income	0.0				(0.1)
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	447.6				1,321.4
Cost of Goods and Services Sold	299.2				865.2
Gross profit	148.4				456.2
Income before income taxes	43.3				140.0
Consolidated net income	$ 31.7				$ 100.1

[1] We attribute revenue to a geography based upon the location of the business unit that consummates the external sale.