Summary of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses), tax	$ 1	$ 3	$ (1)	$ 2
Net change related to other comprehensive income (loss), tax	(1)	1	(2)	(3)
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses), tax	(111)	234	45	148
Net change related to other comprehensive income (loss), tax	(112)	234	44	164
Translation adjustments and other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net change related to other comprehensive income (loss), tax	$ 0	$ (1)	$ (8)	$ (1)