Other Income (Expenses) - Schedule of Other Income (Expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other Income and Expenses [Abstract]
Dividend income	$ 25.6	$ 4.7
Interest income	9.0	23.8
Gains (losses) on investments, net	(15.8)	0.6
Income (losses) from investments in equity method investees	(37.6)	35.2
Gains (losses) on investments of CIPs, net	(49.0)	16.0
Rental income	4.9	3.7
Foreign currency exchange gains (losses), net	4.7	(2.9)
Other income, net		0.2
Other expense, net	(0.9)
Total	(59.1)	81.3
Interest Expense	(6.4)	(10.8)
Other Income (Expenses), Net	$ (65.5)	$ 70.5