Investments in Marketable Securities - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Mar. 31, 2022
Marketable Securities [Abstract]
Fair value option elected	$ 617,000,000		$ 617,000,000		$ 674,000,000
Available-for-sale debt securities unrealized loss			$ 98,000,000		$ 41,000,000
Private placement share redemption percentage	1.00%		1.00%
Private placement share redemption amount	$ 250,000		$ 250,000
Share redemption period			90 days
Non-cash investing activities related to in-kind transactions	$ 0	$ 0	$ 0	$ 1,100,000,000