Other Income (Expenses) - Schedule of Other Income (Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Other Income and Expenses [Abstract]
Dividend income	$ 18.6	$ 25.6
Interest income	5.4	9.0
Income (losses) from investments in equity method investees	39.1	(37.6)
Rental income	7.5	4.9
Foreign currency exchange (losses) gains, net	(8.5)	4.7
Other, net	(2.0)	(0.9)
Total	59.6	(59.1)
Interest Expense	(6.7)	(6.4)
Other Income (Expenses), Net	52.9	(65.5)
Schedule Of Consolidated Investment Products [Line Items]
Gains (losses) on investments, net	7.8	(15.8)
CIPs [Member]
Schedule Of Consolidated Investment Products [Line Items]
Gains (losses) on investments, net	$ (8.3)	$ (49.0)