Income Taxes (Components of the Income Taxes Provision) (Details) - USD ($) $ in Millions	3 Months Ended											12 Months Ended
	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016		Sep. 30, 2015	Sep. 30, 2014
Current Income Tax Expense
Federal, Current												$ 237.9		$ 177.1	$ 19.3
State, Current												29.1		16.9	13.0
Foreign, Current												256.6		221.4	211.6
Current Tax Provision												523.6		415.4	243.9
Deferred Income Tax Expense
Federal, Deferred												42.2		(3.5)	98.2
State, Deferred												3.6		19.1	(2.7)
Foreign, Deferred												17.1		(12.7)	30.0
Deferred Tax Provision												62.9		2.9	125.5
Income tax provision	$ 138.6		$ 179.5		$ 132.5		$ 135.9	$ 119.4	$ 104.1	$ 87.7	$ 107.1	$ 586.5	[1]	$ 418.3	$ 369.4

[1] Includes income tax expense for tax costs associated with business separation. For additional information, see Note 3, Materials Technologies Separation.