Acquisitions (Pro Forma Revenue) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
Jan. 28, 2018	Jan. 29, 2017	Jan. 28, 2018	Jan. 29, 2017
Business Combinations [Abstract]
Business Acquisition, Pro Forma Revenue	$ 2,210	$ 2,234	$ 4,449	$ 4,506
Business Acquisition, Pro Forma Net Income (Loss)	$ 285	$ 102	$ 563	$ 394
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 0.95	$ 0.33	$ 1.86	$ 1.28

The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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