Share Repurchases (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Oct. 30, 2016	Nov. 01, 2015
Statement [Line Items]
Shares repurchased, value	$ 112	$ 32
June 2011 Program [Member]
Statement [Line Items]
Authorized amount for shares repurchase	1,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 350
Treasury Stock [Member]
Statement [Line Items]
Treasury stock purchased, shares	2	1
Shares repurchased, value	$ 112	$ 32
Treasury Stock [Member] | June 2011 Program [Member]
Statement [Line Items]
Shares repurchased, value	$ 100