Net Income Per Share (Calculation Of Basic And Diluted Net Income Per Share) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 28, 2012	Jan. 29, 2011	Jan. 28, 2012	Jan. 29, 2011
Net Income Per Share [Abstract]
Net income	$ 2,182	$ 1,521	$ 3,959	$ 3,451
Weighted-average shares-basic	5,368	5,531	5,381	5,563
Effect of dilutive potential common shares	33	56	23	67
Weighted-average shares-diluted	5,401	5,587	5,404	5,630
Net income per share-basic	$ 0.41	$ 0.27	$ 0.74	$ 0.62
Net income per share-diluted	$ 0.40	$ 0.27	$ 0.73	$ 0.61
Antidilutive employee share-based awards, excluded	532	351	692	340