Segments - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Net sales	$ 685.1	$ 587.0	$ 1,533.7	$ 1,323.8
Segment Profit	270.5	235.6	608.4	536.9
Research and development expense	9.0	8.3	16.6	17.2
Amortization of intangible assets	(15.3)	(14.2)	(30.8)	(28.0)
Loss on extinguishment of debt	(70.0)	0.0	(75.7)	(4.2)
Other items, net	0.1	(5.2)	(0.6)	(4.3)
Loss / (earnings) before income taxes	(13.7)	21.9	73.6	80.6
Acquisition foreign currency gains			12.3
Acquisition and integration costs	16.8	16.9	35.1	36.2
Operating Segments
Segment Reporting Information [Line Items]
Segment Profit	171.9	142.2	387.6	323.6
Segment Reconciling Items
Segment Reporting Information [Line Items]
General corporate and other expenses	(25.8)	(23.5)	(49.8)	(48.4)
Global marketing expense	(9.5)	(5.6)	(18.9)	(11.7)
Research and development expense	8.1	7.7	15.6	16.2
Amortization of intangible assets	(15.3)	(14.2)	(30.8)	(28.0)
Acquisition and integration costs	16.8	16.9	35.1	36.2
Acquisition earn out	(1.1)	0.0	(1.1)	0.0
Interest and other financing items	(39.1)	(47.2)	(86.4)	(94.0)
Americas
Segment Reporting Information [Line Items]
Net sales	482.0	409.9	1,068.6	924.4
Americas | Operating Segments
Segment Reporting Information [Line Items]
Net sales	482.0	409.9	1,068.6	924.4
Segment Profit	132.3	101.8	288.2	231.0
International
Segment Reporting Information [Line Items]
Net sales	203.1	177.1	465.1	399.4
Acquisition foreign currency gains			11.9
International | Operating Segments
Segment Reporting Information [Line Items]
Net sales	203.1	177.1	465.1	399.4
Segment Profit	39.6	40.4	99.4	92.6
Selling, general and administrate expense
Segment Reporting Information [Line Items]
Global marketing expense	(4.7)	(2.6)	(9.6)	(5.5)
Acquisition and integration costs	8.6	8.1	19.0	19.2
Advertising and Sales Promotion Expense
Segment Reporting Information [Line Items]
Global marketing expense	(4.8)	(3.0)	(9.3)	(6.2)
Research and Development Expense
Segment Reporting Information [Line Items]
Acquisition and integration costs	0.9	0.6	1.0	1.0
Acquisition and integration costs	$ 0.9	$ 0.6	$ 1.0	$ 1.0