Consolidated Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 26, 2013	Oct. 27, 2012
Other Comprehensive Income (Loss), Tax [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	$ (53)	$ 1
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	31	10
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	(3)	0
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	$ (3)	$ (10)