Earnings Per Share Earnings Per Share (Computation of Basic and Diluted Earnings Per Share) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Aug. 03, 2014	Apr. 27, 2014	Jan. 26, 2014	Oct. 27, 2013	Jul. 28, 2013	Apr. 28, 2013	Jan. 27, 2013	Oct. 28, 2012	Aug. 03, 2014		Jul. 28, 2013		Jul. 29, 2012
Income (Loss) from Continuing Operations Attributable to Parent									$ 737		$ 689		$ 734
Earnings (loss) from discontinued operations	0	0	90	(9)	(275)	12	19	13	81		(231)		40
Net Income (Loss) Attributable to Parent	137	184	325	172	(158)	181	190	245	818		458		774
Participating Securities, Distributed and Undistributed Earnings									0		0		(5)
Net Income (Loss) Available to Common Stockholders, Basic									818		458		769
Weighted Average Number of Shares Outstanding, Basic									314		314		317
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements									2		3		2
Weighted Average Number of Shares Outstanding, Diluted									316		317		319
Earnings (Loss) from Continuing Operations, Per Basic Share	$ 0.44	$ 0.59	$ 0.75	$ 0.58	$ 0.37	$ 0.54	$ 0.54	$ 0.74	$ 2.35		$ 2.19		$ 2.30
Earnings (Loss) from Continuing Operations, Per Diluted Share	$ 0.43	$ 0.58	$ 0.74	$ 0.57	$ 0.37	$ 0.53	$ 0.54	$ 0.73	$ 2.33		$ 2.17		$ 2.29
Earnings (loss) from discontinued operations, Per Basic Share	$ 0.00	$ 0.00	$ 0.29	$ (0.03)	$ (0.88)	$ 0.04	$ 0.06	$ 0.04	$ 0.26		$ (0.74)		$ 0.12
Earnings (loss) from discontinued operations, Per Diluted Share	$ 0.00	$ 0.00	$ 0.28	$ (0.03)	$ (0.87)	$ 0.04	$ 0.06	$ 0.04	$ 0.26		$ (0.73)		$ 0.12
Earnings Per Share, Basic	$ 0.44	$ 0.59	$ 1.04	$ 0.55	$ (0.50)	$ 0.58	$ 0.61	$ 0.78	$ 2.61	[1]	$ 1.46	[1]	$ 2.43	[1]
Earnings Per Share, Diluted	$ 0.43	$ 0.58	$ 1.03	$ 0.54	$ (0.50)	$ 0.57	$ 0.60	$ 0.78	$ 2.59	[1]	$ 1.44	[1]	$ 2.41	[1]
Continuing Operations [Member]
Participating Securities, Distributed and Undistributed Earnings									0		0		(4)
Net Income (Loss) Available to Common Stockholders, Basic									737		689		730
Discontinued Operations [Member]
Earnings (loss) from discontinued operations									81		(231)		40
Participating Securities, Distributed and Undistributed Earnings									0		0		(1)
Net Income (Loss) Available to Common Stockholders, Basic									$ 81		$ (231)		$ 39

[1] The sum of the individual per share amounts may not add due to rounding.