Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service costs	$ 0.1	$ 0.2
Interest costs	1.5	1.5
Expected return on plan assets	(2.7)	(2.7)
Amortization of net loss	0.4	0.5
Net periodic pension (benefit) cost	(0.7)	(0.5)
Non-U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service costs	0.5	0.5
Interest costs	0.2	0.2
Expected return on plan assets	(0.2)	(0.2)
Amortization of net loss	0.6	0.7
Net periodic pension (benefit) cost	$ 1.1	$ 1.2