Income Taxes (Aggregate Changes in Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 29, 2017	Jul. 30, 2016	Jul. 25, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 1,627	$ 2,029	$ 1,938
Additions based on tax positions related to the current year	336	255	276
Additions for tax positions of prior years	180	116	137
Reductions for tax positions of prior years	(78)	(457)	(30)
Settlements	(43)	(241)	(165)
Lapse of statute of limitations	(49)	(75)	(127)
Ending balance	$ 1,973	$ 1,627	$ 2,029