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. 27, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 28, 2018	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 27, 2019	Jul. 28, 2018	Jul. 29, 2017
Earnings Per Share [Abstract]
Net income	$ 2,206	$ 3,044	$ 2,822	$ 3,549	$ 3,803	$ 2,691	$ (8,778)	$ 2,394	$ 11,621	$ 110	$ 9,609
Weighted-average shares—basic (In shares)									4,419	4,837	5,010
Effect of dilutive potential common shares (in shares)									34	44	39
Weighted-average shares—diluted (in shares)									4,453	4,881	5,049
Net income per share—basic (in dollars per share)	$ 0.52	$ 0.70	$ 0.63	$ 0.78	$ 0.81	$ 0.56	$ (1.78)	$ 0.48	$ 2.63	$ 0.02	$ 1.92
Net income per share—diluted (in dollars per share)	$ 0.51	$ 0.69	$ 0.63	$ 0.77	$ 0.81	$ 0.56	$ (1.78)	$ 0.48	$ 2.61	$ 0.02	$ 1.90
Antidilutive employee share-based awards, excluded (in shares)									55	61	136