Income Taxes (Details 2) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Deferred income tax assets:
Compensation and benefits	$ 16.2	$ 28.4
Inventory	18.0	15.3
Returns, rebates and incentives	55.1	50.8
Retirement benefits	493.6	371.2
Environmental remediation and other site-related costs	34.8	31.1
Share-based compensation	40.6	35.5
Other accruals and reserves	60.5	48.9
Net operating loss carryforwards	24.4	25.9
Tax credit carryforwards	13.7	8.5
Capital loss carryforwards	9.9	13.6
Other	11.4	15.9
Subtotal	778.2	645.1
Valuation allowance	(17.3)	(22.2)
Net deferred income tax assets	760.9	622.9
Deferred income tax liabilities:
Property	(63.5)	(74.9)
Intangible assets	(54.9)	(53.2)
Other	(8.6)	0.0
Deferred income tax liabilities	(127.0)	(128.1)
Total net deferred income tax assets	$ 633.9	$ 494.8