Available-for-Sale Debt and Equity Investments - Available-for-Sale Investments With Gross Unrealized Losses (Details) - USD ($) $ in Millions	Jan. 29, 2022	Jul. 31, 2021
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	$ 7,360	$ 2,910
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(141)	(15)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value	290	19
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses	(13)	0
TOTAL, Fair Value	7,650	2,929
TOTAL, Gross Unrealized Losses	(154)	(15)
U.S. government securities
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	1,124	468
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(19)	0
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value	2	0
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses	0	0
TOTAL, Fair Value	1,126	468
TOTAL, Gross Unrealized Losses	(19)	0
U.S. government agency securities
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	125	26
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(1)	0
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value	15	0
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses	(1)	0
TOTAL, Fair Value	140	26
TOTAL, Gross Unrealized Losses	(2)	0
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	4,230	1,086
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(69)	(5)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value	182	6
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses	(8)	0
TOTAL, Fair Value	4,412	1,092
TOTAL, Gross Unrealized Losses	(77)	(5)
U.S. agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value	1,881	1,293
UNREALIZED LOSSES LESS THAN 12 MONTHS, Gross Unrealized Losses	(52)	(10)
UNREALIZED LOSSES 12 MONTHS OR GREATER, Fair Value	91	13
UNREALIZED LOSSES 12 MONTHS OR GREATER, Gross Unrealized Losses	(4)	0
TOTAL, Fair Value	1,972	1,306
TOTAL, Gross Unrealized Losses	$ (56)	(10)
Commercial paper
Debt Securities, Available-for-sale [Line Items]
UNREALIZED LOSSES LESS THAN 12 MONTHS, Fair Value		37
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		37
TOTAL, Gross Unrealized Losses		$ 0