Income Taxes (Significant Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Gross Deferred Tax Assets
Tax loss carryforwards	$ 132.2	$ 141.8
Revenue recognition	100.3	38.8
Reserves and accruals	83.1	65.2
Retirement benefits and compensation accruals	62.5	75.2
Tax credits and other tax carryforwards	45.5	46.2
Currency losses	12.6	0.0
Valuation allowance	(158.4)	(153.3)
Other	44.6	42.5
Deferred Tax Assets	322.4	256.4
Gross Deferred Tax Liabilities
Plant and equipment	1,205.8	1,192.0
Currency gains	0.0	20.6
Unremitted earnings of foreign entities	103.4	72.0
Partnership and other investments	19.2	18.6
Intangible assets	17.3	48.5
Other	8.8	11.1
Deferred Tax Liabilities	1,354.5	1,362.8
Net Deferred Income Tax Liability	$ 1,032.1	$ 1,106.4