Supplemental Financial Statement Information, Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019
Income Statement Related Disclosures [Abstract]
Interest income	$ (0.2)	$ (0.3)	$ (0.4)	$ (1.3)
Foreign currency exchange loss/(gain)	2.9	(0.3)	8.0	2.4
Pension benefit other than service costs	(0.5)	(0.7)	(1.5)	(2.1)
Other	(1.1)	0.3	(0.7)	0.3
Acquisition foreign currency loss/(gain)	0.0	0.9	2.2	(8.1)
Interest income on restricted cash	0.0	0.0	0.0	(5.8)
Transition services agreement income	(0.4)	(0.7)	(0.8)	(0.8)
Gain on sale of assets	0.0	0.0	(1.0)	0.0
Total Other items, net	0.7	$ (0.8)	5.8	$ (13.9)
Inventories
Raw materials and supplies	103.3		103.3		$ 70.5
Work in process	139.1		139.1		103.7
Finished products	276.2		276.2		295.1
Total inventories	518.6		518.6		469.3
Other Current Assets
Miscellaneous receivables	18.1		18.1		16.5
Due from Spectrum	34.7		34.7		7.6
Prepaid expenses	96.4		96.4		71.3
Value added tax collectible from customers	23.9		23.9		23.1
Other	12.9		12.9		58.6
Total other current assets	186.0		186.0		177.1
Property, Plant and Equipment
Land	9.0		9.0		9.6
Buildings	119.6		119.6		119.9
Machinery and equipment	824.2		824.2		823.0
Capital leases	45.7		45.7		50.4
Construction in progress	36.0		36.0		25.8
Total gross property	1,034.5		1,034.5		1,028.7
Accumulated depreciation	(689.6)		(689.6)		(666.7)
Total property, plant and equipment, net	344.9		344.9		362.0
Other Current Liabilities
Accrued advertising, sales promotion and allowances	11.2		11.2		11.8
Accrued trade allowances	22.9		22.9		53.1
Accrued salaries, vacations and incentive compensation	43.9		43.9		59.2
Accrued interest expense	63.0		63.0		37.4
Due to Spectrum	1.1		1.1		2.6
Accrued acquisition and integration costs	1.0		1.0		7.9
Restructuring reserve	13.2		13.2		9.8
Income taxes payable	29.3		29.3		23.4
Other	164.4		164.4		128.4
Total other current liabilities	350.0		350.0		333.6
Other Liabilities
Pensions and other retirement benefits	101.1		101.1		109.0
Deferred compensation	26.3		26.3		28.1
Restructuring reserve	0.7		0.7		0.0
Mandatory transition tax	16.7		16.7		16.7
Other non-current liabilities	73.9		73.9		50.8
Total other liabilities	$ 218.7		$ 218.7		$ 204.6