Share Repurchases (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended
	Nov. 02, 2014	Oct. 27, 2013
Statement [Line Items]
Shares repurchased, value	$ 73	$ 2
June 2011 Program [Member]
Statement [Line Items]
Authorized amount for shares repurchase	1,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	700
Treasury Stock [Member]
Statement [Line Items]
Treasury stock purchased, shares	2,000	0
Shares repurchased, value	73	2
Treasury Stock [Member] | June 2011 Program [Member]
Statement [Line Items]
Shares repurchased, value	$ 50
Treasury Stock [Member] | Shares Repurchased To Offset The Impact Of Dilution [Member]
Statement [Line Items]
Treasury stock purchased, shares		43