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. 28, 2018	Apr. 28, 2018	Jan. 27, 2018	Oct. 28, 2017	Jul. 29, 2017	Apr. 29, 2017	Jan. 28, 2017	Oct. 29, 2016	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 3,803	$ 2,691	$ (8,778)	$ 2,394	$ 2,424	$ 2,515	$ 2,348	$ 2,322	$ 110	$ 9,609	$ 10,739
Weighted-average shares—basic (In shares)									4,837	5,010	5,053
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements									44	39	35
Weighted-average shares—diluted (in shares)									4,881	5,049	5,088
Net income per share—basic (in dollars per share)	$ 0.81	$ 0.56	$ (1.78)	$ 0.48	$ 0.49	$ 0.50	$ 0.47	$ 0.46	$ 0.02	$ 1.92	$ 2.13
Net income per share—diluted (in dollars per share)	$ 0.81	$ 0.56	$ (1.78)	$ 0.48	$ 0.48	$ 0.50	$ 0.47	$ 0.46	$ 0.02	$ 1.90	$ 2.11
Antidilutive employee share-based awards, excluded (in shares)									61	136	148