Restructuring, Reserve (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020
Restructuring Reserve [Roll Forward]
Restructuring reserve			$ 9.4
2020 Restructuring Program
Restructuring Reserve [Roll Forward]
44104	$ 1.2
Charge to Income	9.4
Cash	8.7
Non-Cash	0.0
March 31, 2020	1.9
2019 Restructuring Program
Restructuring Reserve [Roll Forward]
44104	8.2	$ 9.8
Charge to Income	12.4	13.7
Cash	13.4	4.2
Non-Cash	2.8	5.9
March 31, 2020	4.4	13.4
Other Liabilities
Restructuring Reserve [Roll Forward]
Restructuring reserve	6.3
Severance & termination related costs | 2020 Restructuring Program
Restructuring Reserve [Roll Forward]
44104	0.4
Charge to Income	0.2
Cash	0.6
Non-Cash	0.0
March 31, 2020	0.0
Severance & termination related costs | 2019 Restructuring Program
Restructuring Reserve [Roll Forward]
44104	5.3	9.8
Charge to Income	(0.1)	1.1
Cash	3.2	0.0
Non-Cash	0.0	0.0
March 31, 2020	2.0	10.9
Accelerated depreciation & asset write-offs | 2019 Restructuring Program
Restructuring Reserve [Roll Forward]
44104	0.0	0.0
Charge to Income	2.8	5.9
Cash	0.0	0.0
Non-Cash	2.8	5.9
March 31, 2020	0.0	0.0
Other exit costs | 2020 Restructuring Program
Restructuring Reserve [Roll Forward]
44104	0.8
Charge to Income	9.2
Cash	8.1
Non-Cash	0.0
March 31, 2020	1.9
Other exit costs | 2019 Restructuring Program
Restructuring Reserve [Roll Forward]
44104	2.9	0.0
Charge to Income	9.7	6.7
Cash	10.2	4.2
Non-Cash	0.0	0.0
March 31, 2020	$ 2.4	$ 2.5