Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Deferred income tax assets
Compensation and benefits	$ 26.7	$ 41.7
Inventory	10.4	12.8
Returns, rebates and incentives	61.7	37.5
Retirement benefits	80.7	153.1
Environmental remediation and other site-related costs	23.6	22.8
Share-based compensation	21.5	18.5
Other accruals and reserves	249.9	250.2
Net operating loss carryforwards	85.2	130.4
Tax credit carryforwards	19.3	20.3
Capital loss carryforwards	13.0	15.3
Other	10.7	23.7
Subtotal	602.7	726.3
Valuation allowance	(23.1)	(32.6)
Net deferred income tax assets	579.6	693.7
Deferred income tax liabilities
Property	(36.9)	(43.7)
Intangible assets	(149.8)	(160.5)
Investments	(26.0)	(64.3)
Unremitted earnings of foreign subsidiaries	(20.0)	(42.0)
Other	(2.1)	(2.3)
Deferred income tax liabilities	(234.8)	(312.8)
Total net deferred income tax assets	$ 344.8	$ 380.9