Income Taxes (Components of the Income Taxes Provision) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Current Tax Provision
Federal									$ 26.9	$ 163.7	$ 305.1
State									23.8	23.3	17.7
Foreign									262.7	235.5	256.9
Total Current Tax Provision									313.4	422.5	579.7
Deferred Tax Provision
Federal									108.8	9.7	(121.7)
State									(3.6)	2.4	12.5
Foreign									59.8	45.5	53.8
Total Deferred Tax Provision									165.0	57.6	(55.4)
Total Income Tax Provision	$ 99.9	$ 109.3	$ 148.5	$ 120.7	$ 131.2	$ 109.3	$ 107.5	$ 132.1	$ 478.4	$ 480.1	$ 524.3