Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Jul. 30, 2017	Jul. 31, 2016	Aug. 02, 2015
Statement [Line Items]
Common Stock, Shares Authorized	560	560
Common Stock, Par or Stated Value Per Share	$ 0.0375	$ 0.0375
Preferred Stock, Shares Authorized	40	40
Preferred Stock, Shares Issued	0	0
Shares repurchased, value	$ 437	$ 143	$ 244
March 2017 Program [Member]
Statement [Line Items]
Authorized amount for shares repurchase	1,500
Shares repurchased, value	129
Stock Repurchase Program, Remaining Authorized Repurchase Amount	1,371
June 2011 Program [Member]
Statement [Line Items]
Authorized amount for shares repurchase	1,000
Shares repurchased, value	$ 271
Treasury Stock [Member]
Statement [Line Items]
Treasury stock purchased, shares	8	3	5
Shares repurchased, value	$ 437	$ 143	$ 244