Summary of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses), tax	$ 7	$ 3	$ 8	$ 7
Net change related to other comprehensive income (loss), tax	7	1	6	(1)
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses), tax	(186)	307	(347)	197
Net change related to other comprehensive income (loss), tax	(331)	34	(949)	(457)
Translation adjustments and other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net change related to other comprehensive income (loss), tax	$ 0	$ 0	$ (1)	$ 7