Investments - Schedule of Total Gains and Losses on Equity Securities (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Schedule of Investments [Abstract]
Total (losses) gains recognized on equity securities	$ (11)	$ (9)	$ (14)	$ 19
Less: Net gains recognized on equity securities sold	2	0	2	0
Unrealized (losses) gains recognized on equity securities held at end of period	$ (13)	$ (9)	$ (16)	$ 19