Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Net benefit related to equity affiliate from India Finance Act			$ 13.5
Proportionate share of accumulated dividend distribution taxes released per the India Finance Act			33.8
Income tax provision related to estimated withholding taxes on future dividends			$ 20.3
Discrete net tax expense related to Tax Act		$ 3.2		$ 43.8
Reversal of non-recurring benefit related to U.S. taxation of deemed foreign dividends				56.2
Tax benefit related to finalization of assessment of impacts of Tax Act				$ 12.4
Effective tax rate (percent)	19.30%	17.90%	20.70%	21.30%
Income tax payments, net of refunds			$ 329.6	$ 250.8