Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service costs	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Interest costs	2.8	1.6	5.6	3.1
Expected return on plan assets	(3.4)	(2.7)	(6.8)	(5.4)
Amortization of net loss (gain)	0.1	0.4	0.2	0.8
Net periodic pension (benefit) cost	(0.5)	(0.7)	(1.0)	(1.5)
Non-U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service costs	0.5	0.6	1.0	1.1
Interest costs	1.0	0.2	1.9	0.4
Expected return on plan assets	(0.2)	(0.3)	(0.5)	(0.5)
Amortization of net loss (gain)	(0.2)	0.0	(0.4)	0.6
Net periodic pension (benefit) cost	$ 1.1	$ 0.5	$ 2.0	$ 1.6