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								12 Months Ended
	Jul. 25, 2020	Apr. 25, 2020	Jan. 25, 2020	Oct. 26, 2019	Jul. 27, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 25, 2020	Jul. 27, 2019	Jul. 28, 2018
Earnings Per Share [Abstract]
Net income	$ 2,636	$ 2,774	$ 2,878	$ 2,926	$ 2,206	$ 3,044	$ 2,822	$ 3,549	$ 11,214	$ 11,621	$ 110
Weighted-average shares—basic (In shares)									4,236	4,419	4,837
Effect of dilutive potential common shares (in shares)									18	34	44
Weighted-average shares—diluted (in shares)									4,254	4,453	4,881
Net income per share—basic (in dollars per share)	$ 0.62	$ 0.66	$ 0.68	$ 0.69	$ 0.52	$ 0.70	$ 0.63	$ 0.78	$ 2.65	$ 2.63	$ 0.02
Net income per share—diluted (in dollars per share)	$ 0.62	$ 0.65	$ 0.68	$ 0.68	$ 0.51	$ 0.69	$ 0.63	$ 0.77	$ 2.64	$ 2.61	$ 0.02
Antidilutive employee share-based awards, excluded (in shares)									76	55	61