Retirement Plans (Schedule of Fair Value of Plan Assets Measured at NAV) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 363.9	$ 398.2
Fair value measured at net asset value per share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	228.9	44.6
US Equity securities | Fair value measured at net asset value per share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	48.9	11.4
Non-US equity securities | Fair value measured at net asset value per share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	21.4	$ 33.2
US Government Agencies Debt Securities | Fair value measured at net asset value per share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 158.6