Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ 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
Quarterly Financial Information (Unaudited)
Sales	$ 1,607.5	$ 1,575.2	$ 1,550.8	$ 1,574.4	$ 1,781.8	$ 1,649.5	$ 1,600.5	$ 1,591.7	$ 6,307.9	$ 6,623.5	$ 6,351.9
Gross profit	664.2	678.2	673.2	687.5	752.9	681.5	655.8	663.7	2,703.1	2,753.9	2,573.8
Income before income taxes	278.9	284.6	276.5	287.5	339.0	274.0	248.4	272.8	1,127.5	1,134.2	980.9
Net income	$ 201.3	$ 206.1	$ 206.0	$ 214.2	$ 248.7	$ 199.7	$ 180.3	$ 198.1	$ 827.6	$ 826.8	$ 756.3
Basic earnings per share:
Basic	$ 1.51	$ 1.53	$ 1.53	$ 1.58	$ 1.81	$ 1.44	$ 1.30	$ 1.43	$ 6.15	$ 5.98	$ 5.43
Diluted earnings per share:
Diluted	$ 1.50	$ 1.52	$ 1.51	$ 1.56	$ 1.79	$ 1.43	$ 1.28	$ 1.41	$ 6.09	$ 5.91	$ 5.36