Retirement Plans (Schedules of Amounts Recognized in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Amounts recognized in the Consolidated Balance Sheets
Noncurrent liabilities	$ (58.2)	$ (57.9)
Pension plan
Amounts recognized in the Consolidated Balance Sheets
Noncurrent assets	13.5	12.0
Current liabilities	(1.0)	(0.9)
Noncurrent liabilities	(53.5)	(52.3)
Net amount recognized	(41.0)	(41.2)
Amounts recognized in Accumulated other comprehensive loss
Net loss (gain)	119.3	128.6
Prior service credit	0.0	0.0
Net amount recognized, pre-tax	119.3	128.6
Postretirement plan
Amounts recognized in the Consolidated Balance Sheets
Noncurrent assets	0.0	0.0
Current liabilities	(0.2)	(0.2)
Noncurrent liabilities	(3.7)	(3.9)
Net amount recognized	(3.9)	(4.1)
Amounts recognized in Accumulated other comprehensive loss
Net loss (gain)	(7.3)	(7.4)
Prior service credit	0.0	0.0
Net amount recognized, pre-tax	$ (7.3)	$ (7.4)