Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Accrued liabilities	$ 32.4	$ 40.9
Deferred and stock-related compensation	14.0	16.9
Tax loss carryforwards and tax credits	29.6	13.4
Intangible assets	3.3	0.6
Pension plans	22.1	12.2
Inventory differences and other tax assets	6.6	2.1
Interest expense limited under Sec 163j	34.8	0.0
Gross deferred tax assets	142.8	86.1
Depreciation and property differences	(26.7)	(16.2)
Intangible assets	(249.1)	(38.1)
Other tax liabilities	(2.9)	(2.2)
Gross deferred tax liabilities	(278.7)	(56.5)
Valuation allowance	(11.9)	(12.0)
Net deferred tax (liabilities)/assets	$ (147.8)
Net deferred tax (liabilities)/assets		$ 17.6