Net Income (Loss) per Share (Calculation of Basic and Diluted Net Income per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Apr. 27, 2019	Apr. 28, 2018	Apr. 27, 2019	Apr. 28, 2018
Earnings Per Share [Abstract]
Net income	$ 3,044	$ 2,691	$ 9,415	$ (3,693)
Weighted-average shares—basic (in shares)	4,370	4,791	4,468	4,892
Effect of dilutive potential common shares (in shares)	45	53	41	0
Weighted-average shares—diluted (in shares)	4,415	4,844	4,509	4,892
Net income (loss) per share—basic (in dollars per share)	$ 0.70	$ 0.56	$ 2.11	$ (0.76)
Net income (loss) per share—diluted (in dollars per share)	$ 0.69	$ 0.56	$ 2.09	$ (0.76)
Antidilutive employee share-based awards, excluded (in shares)	5	5	32	32