Comprehensive Income (AOCI Components) (Details) (USD $) In Millions, unless otherwise specified			6 Months Ended		3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended
	Jan. 25, 2014	Jul. 27, 2013	Jan. 25, 2014 Available-for-sale Securities	Jan. 26, 2013 Available-for-sale Securities	Jan. 25, 2014 Derivative	Jan. 26, 2013 Derivative	Jan. 25, 2014 Derivative	Jan. 26, 2013 Derivative	Jan. 25, 2014 Accumulated Translation Adjustment	Jan. 26, 2013 Accumulated Translation Adjustment	Jan. 25, 2014 Parent	Jan. 26, 2013 Parent	Jan. 25, 2014 Parent	Jan. 26, 2013 Parent
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 703	$ 608	$ 379	$ 409			$ 8	$ (53)	$ 221	$ 305			$ 608	$ 661
OCI, Unrealized Holding Gain (Loss) on Securities Arising During Period, before Reclassification & Tax			332	124
Amount Reclassified Out of OCI, Before Tax			(165)	(40)
OCI, Unrealized Gain (Loss) on Derivatives Arising During Period, before Reclassification & Tax							33	69
Amount Reclassified Out of OCI, Before Tax					(19)	(8)	(28)	(3)
OCI, Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax									(14)	135
Amount Reclassified Out of OCI, Before Tax									0	0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent													351	328
Amount Reclassified Out of OCI, Before Tax											(101)	(21)	(193)	(43)
Tax benefit (expense)			(60)	(32)			(2)	1	(1)	(15)			(63)	(48)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 703	$ 608	$ 486	$ 461	$ 11	$ 12	$ 11	$ 12	$ 206	$ 425	$ 703	$ 898	$ 703	$ 898