Other Comprehensive Income (Loss) - Schedule of reclassifications (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Affected Line in the Consolidated Statement of Operations:
Net revenue	[1]	$ 410.3	$ 397.2
Cost of Goods and Services Sold		263.3	251.0
Operating expenses		(90.7)	(89.1)
Other income (expense), net		0.5	(0.4)
Tax expense		(14.5)	(23.7)
Total reclassifications for the period, net of tax	[2]	0.2	0.4
Amortization of Pension and Postretirement
Affected Line in the Consolidated Statement of Operations:
Total reclassifications for the period, net of tax	[2]	0.2	0.7
Derivative Instruments
Affected Line in the Consolidated Statement of Operations:
Total reclassifications for the period, net of tax	[2]	0.0	(0.3)
Reclassifications out of accumulated other comprehensive income (loss)
Affected Line in the Consolidated Statement of Operations:
Net revenue		0.1	(0.4)
Cost of Goods and Services Sold		0.1	0.0
Operating expenses		0.0	0.0
Other income (expense), net		0.3	1.1
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(0.3)	(0.7)
Tax expense		(0.1)	(0.3)
Total reclassifications for the period, net of tax		0.2	0.4
Reclassifications out of accumulated other comprehensive income (loss) | Net Loss Recognized
Affected Line in the Consolidated Statement of Operations:
Net revenue		0.0	0.0
Cost of Goods and Services Sold		0.0	0.0
Operating expenses		0.0	0.0
Other income (expense), net		0.3	1.1
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		(0.3)	(1.1)
Reclassifications out of accumulated other comprehensive income (loss) | Prior Service Costs Recognized
Affected Line in the Consolidated Statement of Operations:
Net revenue		0.0	0.0
Cost of Goods and Services Sold		0.0	0.0
Operating expenses		0.0	0.0
Other income (expense), net		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		0.0	0.0
Reclassifications out of accumulated other comprehensive income (loss) | Derivative Instruments
Affected Line in the Consolidated Statement of Operations:
Net revenue		0.1	(0.4)
Cost of Goods and Services Sold		0.1	0.0
Operating expenses		0.0	0.0
Other income (expense), net		0.0	0.0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		$ 0.0	$ 0.4

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

[2] Amounts are net of tax.