Available-for-Sale Debt and Equity Investments - Available-for-Sale Investments With Gross Unrealized Losses (Details) - USD ($) $ in Millions	May 01, 2021	Jul. 25, 2020
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	$ 3,416	$ 1,358
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(23)	(7)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value	6	3
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses	0	0
TOTAL, Fair Value	3,422	1,361
TOTAL, Gross Unrealized Losses	(23)	(7)
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	468
UNREALIZED LOSSES 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
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	26	33
UNREALIZED LOSSES 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
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	1,242	1,060
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(10)	(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	1,248	1,063
TOTAL, Gross Unrealized Losses	(10)	(6)
U.S. agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	1,618	265
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(13)	(1)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value	0	0
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses	0	0
TOTAL, Fair Value	1,618	265
TOTAL, Gross Unrealized Losses	(13)	$ (1)
Commercial paper
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	46
UNREALIZED LOSSES 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	46
TOTAL, Gross Unrealized Losses	0
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	16
UNREALIZED LOSSES 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	16
TOTAL, Gross Unrealized Losses	$ 0