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. 28, 2017	Jan. 23, 2016	Jan. 28, 2017	Jan. 23, 2016
Earnings Per Share [Abstract]
Net income	$ 2,348	$ 3,147	$ 4,670	$ 5,577
Weighted-average shares—basic (in shares)	5,015	5,070	5,021	5,075
Effect of dilutive potential common shares (in shares)	25	27	33	31
Weighted-average shares—diluted (in shares)	5,040	5,097	5,054	5,106
Net income per share—basic (in dollars per share)	$ 0.47	$ 0.62	$ 0.93	$ 1.10
Net income per share—diluted (in dollars per share)	$ 0.47	$ 0.62	$ 0.92	$ 1.09
Antidilutive employee share-based awards, excluded (in shares)	20	98	103	133