Comprehensive Income (AOCI Components) (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended
	Oct. 26, 2013	Jul. 27, 2013	Oct. 26, 2013 Available-for-sale Securities [Member]	Oct. 27, 2012 Available-for-sale Securities [Member]	Oct. 26, 2013 Derivative [Member]	Oct. 27, 2012 Derivative [Member]	Oct. 26, 2013 Accumulated Translation Adjustment [Member]	Oct. 27, 2012 Accumulated Translation Adjustment [Member]	Oct. 26, 2013 Parent [Member]	Oct. 27, 2012 Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 772	$ 608	$ 379	$ 409	$ 8	$ (53)	$ 221	$ 305	$ 608	$ 661
OCI, Unrealized Holding Gain (Loss) on Securities Arising During Period, before Reclassification & Tax			170	3
Amount Reclassified Out of OCI, Before Tax			(83)	(27)
OCI, Unrealized Gain (Loss) on Derivatives Arising During Period, before Reclassification & Tax					38	66
Amount Reclassified Out of OCI, Before Tax					(9)	5
OCI, Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax							76	124
Amount Reclassified Out of OCI, Before Tax							0	0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent									284	193
Amount Reclassified Out of OCI, Before Tax									(92)	(22)
Tax benefit (expense)			(22)	11	(3)	0	(3)	(10)	(28)	1
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 772	$ 608	$ 444	$ 396	$ 34	$ 18	$ 294	$ 419	$ 772	$ 833