Goodwill and Purchased Intangible Assets - Schedule of Intangible Assets Acquired Through Business Combinations (Details)	12 Months Ended
	Jul. 25, 2020 USD ($) acquisition	Jul. 27, 2019 USD ($) acquisition	Jul. 28, 2018 acquisition
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Number of business combinations (acquisition) | acquisition	6		8
Purchased Intangible Assets	$ 172,000,000	$ 672,000,000
IPR&D
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Indefinite-lived intangible assets acquired	$ 0	333,000,000
TECHNOLOGY
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)	4 years 9 months 18 days
Finite lived intangible assets acquired	$ 161,000,000	166,000,000
CUSTOMER RELATIONSHIPS
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)	4 years 2 months 12 days
Finite lived intangible assets acquired	$ 10,000,000	152,000,000
OTHER
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)	1 year 6 months
Finite lived intangible assets acquired	$ 1,000,000	21,000,000
Duo
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Purchased Intangible Assets		342,000,000
Duo | IPR&D
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Indefinite-lived intangible assets acquired		$ 77,000,000
Duo | TECHNOLOGY
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)		5 years
Finite lived intangible assets acquired		$ 153,000,000
Duo | CUSTOMER RELATIONSHIPS
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)		5 years
Finite lived intangible assets acquired		$ 94,000,000
Duo | OTHER
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)		2 years 6 months
Finite lived intangible assets acquired		$ 18,000,000
Luxtera
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Purchased Intangible Assets		319,000,000
Luxtera | IPR&D
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Indefinite-lived intangible assets acquired		$ 256,000,000
Luxtera | TECHNOLOGY
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)		4 years
Finite lived intangible assets acquired		$ 2,000,000
Luxtera | CUSTOMER RELATIONSHIPS
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)		5 years
Finite lived intangible assets acquired		$ 58,000,000
Luxtera | OTHER
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)		1 year 7 months 6 days
Finite lived intangible assets acquired		$ 3,000,000
Others
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Number of business combinations (acquisition) | acquisition		3
Purchased Intangible Assets		$ 11,000,000
Others | TECHNOLOGY
Schedule Of Finite Lived And Indefinite Lived Intangible Assets Acquired Through Business Combinations [Line Items]
Weighted- Average Useful Life (in Years)		4 years 4 months 24 days
Finite lived intangible assets acquired		$ 11,000,000