Summary of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses), tax	$ (1)	$ 0
Net change related to other comprehensive income (loss), tax	(4)	(1)
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses), tax	(86)	50
Net change related to other comprehensive income (loss), tax	(70)	(144)
Translation adjustments and other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net change related to other comprehensive income (loss), tax	$ 0	$ (1)