Available-for-Sale Debt and Equity Investments - Available-for-Sale Investments With Gross Unrealized Losses (Details) - USD ($) $ in Millions	Jul. 31, 2021	Jul. 25, 2020
Schedule of Investments [Line Items]
Unrealized loss less than 12 months, Fair Value	$ 2,910	$ 1,358
Unrealized loss less than 12 months, Gross Unrealized Losses	(15)	(7)
Unrealized losses 12 months or greater, Fair Value	19	3
Unrealized losses 12 months or greater, Gross Unrealized Losses	0	0
Total, Fair Value	2,929	1,361
Total, Gross Unrealized Losses	(15)	(7)
U.S. government securities
Schedule of Investments [Line Items]
Unrealized loss less than 12 months, Fair Value	468
Unrealized loss less than 12 months, Gross Unrealized Losses	0
Unrealized losses 12 months or greater, Fair Value	0
Unrealized losses 12 months or greater, Gross Unrealized Losses	0
Total, Fair Value	468
Total, Gross Unrealized Losses	0
U.S. government agency securities
Schedule of Investments [Line Items]
Unrealized loss less than 12 months, Fair Value	26	33
Unrealized loss less than 12 months, Gross Unrealized Losses	0	0
Unrealized losses 12 months or greater, Fair Value	0	0
Unrealized losses 12 months or greater, Gross Unrealized Losses	0	0
Total, Fair Value	26	33
Total, Gross Unrealized Losses	0	0
Corporate debt securities
Schedule of Investments [Line Items]
Unrealized loss less than 12 months, Fair Value	1,086	1,060
Unrealized loss less than 12 months, Gross Unrealized Losses	(5)	(6)
Unrealized losses 12 months or greater, Fair Value	6	3
Unrealized losses 12 months or greater, Gross Unrealized Losses	0	0
Total, Fair Value	1,092	1,063
Total, Gross Unrealized Losses	(5)	(6)
U.S. agency mortgage-backed securities
Schedule of Investments [Line Items]
Unrealized loss less than 12 months, Fair Value	1,293	265
Unrealized loss less than 12 months, Gross Unrealized Losses	(10)	(1)
Unrealized losses 12 months or greater, Fair Value	13	0
Unrealized losses 12 months or greater, Gross Unrealized Losses	0	0
Total, Fair Value	1,306	265
Total, Gross Unrealized Losses	(10)	$ (1)
Commercial paper
Schedule of Investments [Line Items]
Unrealized loss less than 12 months, Fair Value	37
Unrealized loss less than 12 months, Gross Unrealized Losses	0
Unrealized losses 12 months or greater, Fair Value	0
Unrealized losses 12 months or greater, Gross Unrealized Losses	0
Total, Fair Value	37
Total, Gross Unrealized Losses	$ 0

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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