Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	9 Months Ended
	Apr. 30, 2022	May 01, 2021
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 41,275	$ 37,920
Other comprehensive income (loss) before reclassifications	(1,139)	230
(Gains) losses reclassified out of AOCI	(32)	(55)
Tax benefit (expense)	125	56
Ending balance	40,400	40,205
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(417)	(519)
Ending balance	(1,463)	(288)
Net Unrealized Gains (Losses) on Available-for-Sale Investments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	182	315
Other comprehensive income (loss) before reclassifications	(717)	(150)
(Gains) losses reclassified out of AOCI	(18)	(46)
Tax benefit (expense)	127	59
Ending balance	(426)	178
Net Unrealized Gains (Losses) Cash Flow Hedging Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(1)	(6)
Other comprehensive income (loss) before reclassifications	63	16
(Gains) losses reclassified out of AOCI	(15)	(12)
Tax benefit (expense)	(11)	(2)
Ending balance	36	(4)
Cumulative Translation Adjustment and Actuarial Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(598)	(828)
Other comprehensive income (loss) before reclassifications	(485)	364
(Gains) losses reclassified out of AOCI	1	3
Tax benefit (expense)	9	(1)
Ending balance	$ (1,073)	$ (462)