Investment and Other Income, net - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Other Income and Expenses [Abstract]
Net gains (losses) recognized on equity securities measured at fair value and trading debt securities	$ (29.2)	$ (2.6)	$ (34.5)	$ 51.2

Amount of unrealized gain (loss) on investment in debt and equity securities.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration