Employee Benefit Plans - Schedule of Pension Plans with a Benefit Obligation in Excess of Plan Assets (Details) - USD ($) $ in Millions	Sep. 30, 2023	Sep. 30, 2022
Plans with projected and accumulated benefit obligations in excess of plan assets
Plans with projected and accumulated benefit obligation in excess of plan assets, benefit obligation	$ 1,101.7	$ 1,177.7
Plans with projected and accumulated benefit obligation in excess of plan assets, plan assets	$ 946.0	$ 996.9