Goodwill And Purchased Intangible Assets (Schedule Of Intangible Assets Acquired Through Business Combinations) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jan. 26, 2013
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired indefinite and finite-lived intangible assets	$ 2,107
IPR&D With Indefinite Lives [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired indefinite lives	108
Technology [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired finite-lived	1,111
Customer Relationships [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired finite-lived	860
Finite Lived Intangible Other [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired finite-lived	28
NDS Group Limited [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired indefinite and finite-lived intangible assets	1,746
NDS Group Limited [Member] | IPR&D With Indefinite Lives [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired indefinite lives	94
NDS Group Limited [Member] | Technology [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	6 years 4 months 24 days
Amount, acquired finite-lived	807
NDS Group Limited [Member] | Customer Relationships [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	6 years 8 months 4 days
Amount, acquired finite-lived	818
NDS Group Limited [Member] | Finite Lived Intangible Other [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	7 years 4 months 24 days
Amount, acquired finite-lived	27
Meraki, Inc. [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired indefinite and finite-lived intangible assets	289
Meraki, Inc. [Member] | Technology [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	8 years
Amount, acquired finite-lived	259
Meraki, Inc. [Member] | Customer Relationships [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	6 years
Amount, acquired finite-lived	30
Other Acquisition [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired indefinite and finite-lived intangible assets	72
Other Acquisition [Member] | IPR&D With Indefinite Lives [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Amount, acquired indefinite lives	14
Other Acquisition [Member] | Technology [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	4 years 8 months 12 days
Amount, acquired finite-lived	45
Other Acquisition [Member] | Customer Relationships [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	5 years 7 months 6 days
Amount, acquired finite-lived	12
Other Acquisition [Member] | Finite Lived Intangible Other [Member]
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted-Average Useful Life (in Years)	7 years
Amount, acquired finite-lived	$ 1