Retirement Plans (Schedule of Benefit Obligations, Plan Assets and Funded Status of the Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Change in plan assets
Estimated fair value of plan assets at beginning of year	$ 570.5
Estimated fair value of plan assets at end of year	398.2	$ 570.5
Pension plan
Change in projected benefit obligation
Benefit obligation at beginning of year	618.7	652.1
Service cost	3.8	4.4	$ 4.3
Interest cost	10.2	9.6	13.5
Actuarial gain	(141.1)	(14.9)
Benefits paid, net	(26.4)	(32.0)
Plan settlements	(4.3)	0.0
Expenses paid	0.0	0.0
Foreign currency exchange rate changes	(21.5)	(0.5)
Projected benefit obligation at end of year	439.4	618.7	652.1
Change in plan assets
Estimated fair value of plan assets at beginning of year	570.5	538.6
Actual return on plan assets	(121.0)	59.7
Company contributions	0.9	4.9
Plan settlements	(4.3)	0.0
Benefits paid	(26.4)	(32.0)
Expenses paid	0.0	0.0
Foreign currency exchange rate changes	(21.5)	(0.7)
Estimated fair value of plan assets at end of year	398.2	570.5	538.6
Funded status at end of year	(41.2)	(48.2)
Postretirement plan
Change in projected benefit obligation
Benefit obligation at beginning of year	5.5	6.0
Service cost	0.0	0.0	0.0
Interest cost	0.2	0.2	0.3
Actuarial gain	(0.9)	(0.8)
Benefits paid, net	(0.3)	(0.2)
Plan settlements	0.0	0.0
Expenses paid	0.0	0.0
Foreign currency exchange rate changes	(0.4)	0.3
Projected benefit obligation at end of year	4.1	5.5	6.0
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	0.3	0.2
Plan settlements	0.0	0.0
Benefits paid	(0.3)	(0.2)
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	$ (4.1)	$ (5.5)