Segments (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Net sales	$ 763.0	$ 658.0	$ 587.0	$ 736.8	$ 719.0	$ 647.2	$ 556.4	$ 571.9	$ 2,744.8	$ 2,494.5	$ 1,797.7
Segment profit	281.8	263.2	235.6	301.3	287.8	246.3	194.2	275.5	1,081.9	1,003.8	830.9
Research and development expense (3)									(35.4)	(32.8)	(22.4)
Amortization of Intangible Assets									(56.5)	(43.2)	(11.5)
Integration	(20.4)	(11.4)	(16.9)	(19.3)	(28.5)	(28.0)	(95.4)	(36.5)	(68.0)	(188.4)	(84.6)
Settlement loss on pension plan terminations									0.0	3.7	14.1
Gain on sale of real estate	$ 3.3	$ (1.7)	$ (3.4)	0.0	$ 1.1	$ 0.8	$ 0.0	$ (1.5)	0.0	0.0	4.6
Loss on extinguishment of debt				$ 4.2					(94.9)	0.0	0.0
Interest expense									(195.0)	(226.0)	(98.4)
Earnings before income taxes									67.7	73.1	175.2
Depreciation and amortization									111.9	92.8	45.1
Segments
Segment Reporting Information [Line Items]
Segment profit									654.3	631.5	475.7
Depreciation and amortization									55.4	49.6	33.6
Segment Reconciling Items
Segment Reporting Information [Line Items]
General corporate and other expenses									(103.8)	(111.5)	(97.3)
Global marketing expenses (2)									(28.2)	(18.2)	(19.0)
Research and development expense (3)									(34.1)	(31.7)	(22.4)
Amortization of Intangible Assets									(56.5)	(43.2)	11.5
Integration									(68.0)	(188.4)	(84.6)
Settlement loss on pension plan terminations									0.0	(3.7)	(14.1)
Gain on sale of real estate									0.0	0.0	4.6
Loss on extinguishment of debt									(94.9)	0.0	0.0
Interest expense									(195.0)	(160.4)	(56.5)
Other financing items, net									(6.1)	(1.3)	0.3
Corporate
Segment Reporting Information [Line Items]
Depreciation and amortization									56.5	43.2	11.5
Selling, General and Administrative Expenses
Segment Reporting Information [Line Items]
General corporate and other expenses									(12.1)	(6.3)	(4.9)
Integration									(38.8)	(82.3)	(62.9)
Advertising and Sales Promotion Expense
Segment Reporting Information [Line Items]
General corporate and other expenses									(16.1)	(11.9)	(14.1)
Other items, net
Segment Reporting Information [Line Items]
Settlement loss on pension plan terminations											14.1
Gain/expense reclassified to acquisitions and integration costs									(4.1)	(19.3)	(20.4)
Cost of products sold
Segment Reporting Information [Line Items]
General corporate and other expenses									(2.9)	(2.3)
Integration									(32.0)	(22.5)	0.0
Interest Expense
Segment Reporting Information [Line Items]
Integration									0.0	(65.6)	(41.9)
Other financing items, net										65.6	41.9
Americas | Segments
Segment Reporting Information [Line Items]
Net sales									1,971.2	1,734.8	1,135.6
Segment profit									498.5	456.6	326.1
Depreciation and amortization									37.9	34.6	21.2
International | Segments
Segment Reporting Information [Line Items]
Net sales									773.6	759.7	662.1
Segment profit									155.8	174.9	149.6
Depreciation and amortization									$ 17.5	$ 15.0	$ 12.4