Investments - Schedule of Total Gains and Losses on Equity Securities (Detail) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Schedule of Investments [Abstract]
Total gains (losses) recognized on equity securities	$ 81	$ (21)	$ (23)
Less: Net losses recognized on equity securities sold or impaired	(1)	0	0
Unrealized gains (losses) recognized on equity securities held at end of period	$ 82	$ (21)	$ (23)