Investment and Other Income , Net - Schedule of Investment and Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Other Income and Expenses [Abstract]
Dividend and interest income	$ 43.1	$ 54.8
Gains (losses) on investments, net	(57.1)	60.1
Income (losses) from investments in equity method investees	(7.6)	56.9
Gains (losses) on derivatives, net	6.6	(8.2)
Rental income	11.2	10.8
Foreign currency exchange gains (losses), net	14.5	(7.4)
Other, net		6.2
Other, net	(0.2)
Investment and other income, net	$ 10.5	$ 173.2

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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