Retirement Plans (Schedule of Benefit Obligations, Plan Assets and Funded Status of the Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Change in plan assets
Estimated fair value of plan assets at beginning of year	$ 412.3
Estimated fair value of plan assets at end of year	417.8	$ 412.3
Pension plan
Change in projected benefit obligation
Benefit obligation at beginning of year	448.4	404.9
Service cost	2.5	1.9	$ 1.9
Interest cost	18.0	21.1	20.6
Actuarial (loss) gain	(25.2)	43.1
Benefits paid, net	(26.6)	(28.4)
Foreign currency exchange rate changes	5.9	5.8
Projected benefit obligation at end of year	423.0	448.4	404.9
Change in plan assets
Estimated fair value of plan assets at beginning of year	412.3	363.9
Actual return on plan assets	17.6	62.8
Company contributions	7.4	7.9
Benefits paid	(26.6)	(28.4)
Foreign currency exchange rate changes	7.1	6.1
Estimated fair value of plan assets at end of year	417.8	412.3	363.9
Funded status at end of year	(5.2)	(36.1)
Postretirement plan
Change in projected benefit obligation
Benefit obligation at beginning of year	4.9	3.9
Service cost	0.0	0.0	0.0
Interest cost	0.2	0.2	0.2
Actuarial (loss) gain	(0.1)	1.0
Benefits paid, net	(0.2)	(0.2)
Foreign currency exchange rate changes	(0.1)	0.0
Projected benefit obligation at end of year	4.7	4.9	3.9
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	0.2
Benefits paid	(0.2)	(0.2)
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	$ (4.7)	$ (4.9)