Income Taxes (Income of U.S and Foreign Operations Before Taxes) (Details) - USD ($) $ in Millions	3 Months Ended									12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	[1]	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017		Sep. 30, 2016	Sep. 30, 2015
Income from Continuing Operations before Taxes
United States										$ 669.8		$ 631.7	$ 507.5
Foreign										666.2		775.9	606.3
Equity affiliates' income	$ 44.8	$ (36.9)		$ 34.2	$ 38.0	$ 39.3	$ 42.1	$ 32.3	$ 33.3	80.1	[1]	147.0	152.3
Income From Continuing Operations Before Taxes										$ 1,416.1		$ 1,554.6	$ 1,266.1

[1] Includes the impact of an other-than-temporary impairment of an investment in an equity affiliate. For additional information, see Note 8, Summarized Financial Information of Equity Affiliates.