Retirement Plans (Schedule of Benefit Obligations, Plan Assets and Funded Status of the Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Change in plan assets
Estimated fair value of plan assets at beginning of year	$ 363.9
Estimated fair value of plan assets at end of year	412.3	$ 363.9
Pension plan
Change in projected benefit obligation
Benefit obligation at beginning of year	404.9	439.4
Service cost	1.9	1.9	$ 3.8
Interest cost	21.1	20.6	10.2
Actuarial (loss) gain	43.1	(12.9)
Benefits paid, net	(28.4)	(29.6)
Plan settlements	0.0	(21.9)
Expenses paid	0.0	0.0
Foreign currency exchange rate changes	5.8	7.4
Projected benefit obligation at end of year	448.4	404.9	439.4
Change in plan assets
Estimated fair value of plan assets at beginning of year	363.9	398.2
Actual return on plan assets	62.8	8.9
Company contributions	7.9	0.9
Plan settlements	0.0	(21.9)
Benefits paid	(28.4)	(29.6)
Expenses paid	0.0	0.0
Foreign currency exchange rate changes	6.1	8.2
Defined Benefit Plan, Plan Assets, Divestiture		(0.8)
Estimated fair value of plan assets at end of year	412.3	363.9	398.2
Funded status at end of year	(36.1)	(41.0)
Postretirement plan
Change in projected benefit obligation
Benefit obligation at beginning of year	3.9	4.1
Service cost	0.0	0.0	0.0
Interest cost	0.2	0.2	0.2
Actuarial (loss) gain	1.0	(0.1)
Benefits paid, net	(0.2)	(0.3)
Plan settlements	0.0	0.0
Expenses paid	0.0	0.0
Foreign currency exchange rate changes	0.0	0.0
Projected benefit obligation at end of year	4.9	3.9	4.1
Change in plan assets
Estimated fair value of plan assets at beginning of year	0.0	0.0
Actual return on plan assets	0.0	0.0
Company contributions	0.2	0.3
Plan settlements	0.0	0.0
Benefits paid	(0.2)	(0.3)
Expenses paid	0.0	0.0
Foreign currency exchange rate changes	0.0	0.0
Estimated fair value of plan assets at end of year	0.0	0.0	$ 0.0
Funded status at end of year	$ (4.9)	$ (3.9)