Goodwill and Purchased Intangible Assets - Schedule of Purchased Intangible Assets with Finite and Indefinite Lives (Details) - USD ($) $ in Millions	Jul. 27, 2019	Jul. 28, 2018
Finite-Lived Intangible Assets [Line Items]
Gross	$ 4,151	$ 5,312
Accumulated Amortization	(2,286)	(2,863)
Net	1,865	2,449
Indefinite-lived Intangible Assets [Abstract]
In-process research and development, with indefinite lives	336	103
Total	4,487	5,415
Total, Net	2,201	2,552
Technology
Finite-Lived Intangible Assets [Line Items]
Gross	3,270	3,711
Accumulated Amortization	(1,933)	(1,888)
Net	1,337	1,823
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross	840	1,538
Accumulated Amortization	(331)	(937)
Net	509	601
Other
Finite-Lived Intangible Assets [Line Items]
Gross	41	63
Accumulated Amortization	(22)	(38)
Net	$ 19	$ 25