Investment and Other Income , Net - Schedule of Investment and Other Income, Net (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Other Income and Expenses [Abstract]
Dividend and interest income	$ 38.9	$ 39.8	$ 101.4	$ 132.6
Gains (losses) on investments, net	(31.4)	(24.3)	(41.7)	17.3
Income from investments in equity method investees	23.0	41.0	38.5	122.3
Gains (losses) on derivatives, net	(8.2)	3.1	(2.7)	(11.5)
Rental income	10.7	11.1	32.8	32.8
Foreign currency exchange (losses) gains, net	(14.4)	1.2	(7.4)	(7.5)
Other, net	4.8	2.6	7.1	14.2
Investment and other income, net	$ 23.4	$ 74.5	$ 128.0	$ 300.2

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

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