Retirement Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Retirement Benefits [Abstract]
Service cost	$ 0.5	$ 0.9	$ 1.4	$ 2.9
Interest cost	5.3	2.6	15.9	7.8
Expected return on plan assets	(5.4)	(5.3)	(16.3)	(15.9)
Recognized net actuarial loss	0.4	1.5	1.2	4.6
Net periodic cost (income)	0.8	$ (0.3)	9.4	$ (0.6)
Defined benefit settlement loss	$ 0.0		$ 7.2