Investments - Schedule of Total Gains and Losses on Equity Securities (Detail) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Schedule of Investments [Abstract]
Total (losses) gains recognized on equity securities	$ (9)	$ (59)	$ 81
Less: Net gains (losses) recognized on equity securities sold or impaired	2	0	(1)
Unrealized (losses) gains recognized on equity securities held at end of period	$ (11)	$ (59)	$ 82