Summary of Changes in Accumulated Other Comprehensive Income (Loss) by Component (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period			$ 87,711
Net change related to other comprehensive income (loss)	$ (925)	$ (1,306)	(1,026)	$ (1,142)
Balance, end of period	78,360	81,829	78,360	81,829
Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	28	315	134	352
Unrealized gains (losses), net of tax	11	449	15	484
Tax expense included in provision for income taxes	1	3	2	6
Amounts reclassified from accumulated other comprehensive income	(18)	(169)	(128)	(241)
Net change related to other comprehensive income (loss)	(7)	280	(113)	243
Balance, end of period	21	595	21	595
Derivatives | Revenue
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification adjustments for gains	(19)	(172)	(130)	(247)
Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	1,537	3,024	1,825	2,941
Unrealized gains (losses), net of tax	(390)	(543)	(317)	(204)
Tax expense included in provision for income taxes	263	243	457	381
Amounts reclassified from accumulated other comprehensive income	(488)	(451)	(849)	(707)
Net change related to other comprehensive income (loss)	(878)	(994)	(1,166)	(911)
Balance, end of period	659	2,030	659	2,030
Investments | Other income (expense), net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification adjustments for gains	(751)	(694)	(1,306)	(1,088)
Translation adjustments and other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(1,039)	(1,381)	(1,332)	(1,499)
Net change related to other comprehensive income (loss)	(40)	(592)	253	(474)
Balance, end of period	(1,079)	(1,973)	(1,079)	(1,973)
Accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	526	1,958	627	1,794
Net change related to other comprehensive income (loss)	(925)	(1,306)	(1,026)	(1,142)
Balance, end of period	$ (399)	$ 652	$ (399)	$ 652