Goodwill and Purchased Intangible Assets (Schedule Of Intangible Assets Acquired Through Business Combinations) (Details) $ in Millions	3 Months Ended	6 Months Ended
Jan. 28, 2017 USD ($) acquisition	Jan. 28, 2017 USD ($) acquisition
Intangible Assets Acquired Through Business Combinations
Number of business combinations \| acquisition		3
Total, Amount	$ 41	$ 41
CloudLock Inc
Intangible Assets Acquired Through Business Combinations
Total, Amount	$ 36	$ 36
Others (two in total)
Intangible Assets Acquired Through Business Combinations
Number of business combinations \| acquisition	2	2
Total, Amount	$ 5	$ 5
IPR&D
Intangible Assets Acquired Through Business Combinations
Indefinite Lives, Amount		0
IPR&D \| CloudLock Inc
Intangible Assets Acquired Through Business Combinations
Indefinite Lives, Amount		0
IPR&D \| Others (two in total)
Intangible Assets Acquired Through Business Combinations
Indefinite Lives, Amount		0
TECHNOLOGY
Intangible Assets Acquired Through Business Combinations
Finite Lives, Amount		$ 37
TECHNOLOGY \| CloudLock Inc
Intangible Assets Acquired Through Business Combinations
Weighted- Average Useful Life (in Years)		6 years
Finite Lives, Amount		$ 32
TECHNOLOGY \| Others (two in total)
Intangible Assets Acquired Through Business Combinations
Weighted- Average Useful Life (in Years)		3 years
Finite Lives, Amount		$ 5
CUSTOMER RELATIONSHIPS
Intangible Assets Acquired Through Business Combinations
Finite Lives, Amount		$ 3
CUSTOMER RELATIONSHIPS \| CloudLock Inc
Intangible Assets Acquired Through Business Combinations
Weighted- Average Useful Life (in Years)		4 years
Finite Lives, Amount		$ 3
CUSTOMER RELATIONSHIPS \| Others (two in total)
Intangible Assets Acquired Through Business Combinations
Weighted- Average Useful Life (in Years)		0 years
Finite Lives, Amount		$ 0
OTHER
Intangible Assets Acquired Through Business Combinations
Finite Lives, Amount		$ 1
OTHER \| CloudLock Inc
Intangible Assets Acquired Through Business Combinations
Weighted- Average Useful Life (in Years)		1 year 6 months
Finite Lives, Amount		$ 1
OTHER \| Others (two in total)
Intangible Assets Acquired Through Business Combinations
Weighted- Average Useful Life (in Years)		0 years
Finite Lives, Amount		$ 0

Schedule of Finite Lived and Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]

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- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

+ Details

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- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

+ Details

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- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

No definition available.

+ Details

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- Definition

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, from an acquisition.

+ References

No definition available.

+ Details

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- Definition

The number of businesses acquired by the entity during the period.

+ References

No definition available.

+ Details

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