Commitments and Contingencies (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended						6 Months Ended		30 Months Ended
	Jan. 23, 2016	Apr. 25, 2015	Jan. 24, 2015	Jan. 25, 2014	Jul. 27, 2013	Apr. 28, 2012	Jan. 23, 2016	Jan. 24, 2015	Jan. 23, 2016	Jul. 25, 2015
Contingency [Line Items]
Purchase Commitments	$ 3,435						$ 3,435		$ 3,435	$ 4,078
Liability for purchase commitments	180						180		180	$ 156
Future compensation expense & contingent consideration, maximum	$ 230						$ 230		$ 230
Commitments and contingencies
Volume of channel partner financing	$ 6,500		$ 6,200				$ 13,400	$ 12,500
Balance of the channel partner financing subject to guarantees	1,200						1,200		$ 1,200	$ 1,200
Financing provided by third parties for leases and loans on which the Company has provided guarantees	16		39				39	65
Cost of Goods Sold	3,480		3,806				7,333	7,725
Brazilian Authority Claim Of Import Tax Evasion By Importer Tax Portion	209						209		209
Brazilian Authority Claim Of Import Tax Evasion By Importer Interest Portion	942						942		942
Brazilian Authority Claim Of Import Tax Evasion By Importer Penalties Portion	$ 929						929		929
Minimum
Contingency [Line Items]
Warranty period for products, in days	90 days
Channel partners revolving short-term financing payment term, in days	60 days
Maximum
Contingency [Line Items]
Warranty period for products, in years	5 years
Channel partners revolving short-term financing payment term, in days	90 days
End User Lease And Loan Term, in years	3 years
Insieme Networks Inc
Contingency [Line Items]
Variable Interest Entities Investment						$ 100
Ownership percentage as a result of investment					83.00%
Compensation expense related to acquisitions	$ 50		$ 51				$ 101	$ 104	724
Description of expected milestone payment							The second milestone payment, to the extent earned, is expected to be paid primarily during the first half of fiscal 2017.
Insieme Networks Inc | Including compensation that has been expensed through current reporting period [Member] | Maximum
Contingency [Line Items]
Commitments and contingencies	839						$ 839		839
Insieme Networks Inc | Partial First Milestone Payment [Member]
Contingency [Line Items]
Compensation expense related to acquisitions							354
Investments In Privately Held Companies
Contingency [Line Items]
Commitments and contingencies	188						188		188	205
Supplier Component Remediation Liability
Contingency [Line Items]
Commitments and contingencies	$ 375			$ 63			$ 375		$ 375	$ 408
Cost of Goods Sold				$ 655
Supplier Component Remediation Liability | Cost of Goods, Product Line [Member]
Contingency [Line Items]
Product Warranty Accrual, Preexisting, Increase (Decrease)		$ 164
Russia and the Commonwealth of Independent States [Member]
Contingency [Line Items]
Percentage of revenue, Percentage	2.00%