Income Taxes (Components of the Income Taxes Provision) (Details) - USD ($) $ in Millions	3 Months Ended												12 Months Ended
	Sep. 30, 2018	[1],[2]	Jun. 30, 2018	Mar. 31, 2018	[2]	Dec. 31, 2017	[1]	Sep. 30, 2017	[3]	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018		Sep. 30, 2017		Sep. 30, 2016
Current Tax Provision
Federal													$ 305.1		$ 62.8		$ 171.0
State													17.7		7.0		21.2
Foreign													256.9		229.1		178.6
Current Tax Provision													579.7		298.9		370.8
Deferred Tax Provision
Federal													(121.7)		1.4		45.0
State													12.5		6.0		2.8
Foreign													53.8		(45.4)		14.0
Deferred Tax Provision													(55.4)		(38.0)		61.8
Income tax provision	$ 69.2		$ 107.1	$ 56.2		$ 291.8		$ (1.3)		$ 89.3	$ 94.5	$ 78.4	$ 524.3	[1],[2]	$ 260.9	[3]	$ 432.6

[1] Includes the impacts of the Tax Act. For additional information, refer to Note 22, Income Taxes.

[2] Includes the impacts of the restructuring of several foreign subsidiaries. For additional information, refer to Note 22, Income Taxes.

[3] Includes the impact of a tax election benefit related to a non-U.S. subsidiary. For additional information, see Note 22, Income Taxes.