Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Components of income before income taxes
United States									$ 660.5	$ 607.3	$ 513.5
Non-United States									467.0	526.9	467.4
Total	$ 278.9	$ 284.6	$ 276.5	$ 287.5	$ 339.0	$ 274.0	$ 248.4	$ 272.8	1,127.5	1,134.2	980.9
Current income tax provision:
United States									238.6	219.4	164.5
Non-United States									73.6	85.3	51.1
State and local									17.0	9.9	15.5
Total current									329.2	314.6	231.1
Deferred income tax provision:
United States									(30.3)	(3.8)	(1.3)
Non-United States									2.6	(4.0)	(2.9)
State and local									(1.6)	0.6	(2.3)
Total deferred									(29.3)	(7.2)	(6.5)
Income tax provision									299.9	307.4	224.6
Total income taxes paid									$ 313.1	$ 323.8	$ 203.9