Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 25, 2015	Apr. 30, 2016	Apr. 25, 2015
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	$ (146)	$ (57)	$ 59	$ (34)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(2)	16	(9)	42
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(2)	2	2	8
Tax expense (benefit) for net (gains) losses reclassified into earnings, cash flow hedges	(2)	(2)	(4)	(5)
Other Comprehensive Income Loss Foreign Currency Translation Adjustment and actuarial gains and losses,Tax	$ (9)	$ 14	$ (43)	$ 50