Retirement Plans (Schedule of Fair Value of Plan Assets Measured at NAV) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 398.2	$ 570.5
Fair value measured at net asset value per share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44.6	74.6
US Equity securities | Fair value measured at net asset value per share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11.4	18.0
Non-US equity securities | Fair value measured at net asset value per share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 33.2	$ 56.6