Net Income per Share - Calculation of Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2021	Jan. 25, 2020	Jan. 23, 2021	Jan. 25, 2020
Earnings Per Share [Abstract]
Net income	$ 2,545	$ 2,878	$ 4,719	$ 5,804
Weighted-average shares—basic (in shares)	4,223	4,242	4,227	4,244
Effect of dilutive potential common shares (in shares)	11	18	12	21
Weighted-average shares—diluted (in shares)	4,234	4,260	4,239	4,265
Net income per share—basic (in dollars per share)	$ 0.60	$ 0.68	$ 1.12	$ 1.37
Net income per share—diluted (in dollars per share)	$ 0.60	$ 0.68	$ 1.11	$ 1.36
Antidilutive employee share-based awards, excluded (in shares)	49	29	56	32