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
	Oct. 28, 2017	Oct. 29, 2016
Earnings Per Share [Abstract]
Net income	$ 2,394	$ 2,322
Weighted-average shares—basic (in shares)	4,959	5,027
Effect of dilutive potential common shares (in shares)	35	39
Weighted-average shares—diluted (in shares)	4,994	5,066
Net income per share—basic (in dollars per share)	$ 0.48	$ 0.46
Net income per share—diluted (in dollars per share)	$ 0.48	$ 0.46
Antidilutive employee share-based awards, excluded (in shares)	15	67