Commitments and Contingencies (Additional Information) (Details) - USD ($) $ in Millions		3 Months Ended					9 Months Ended		33 Months Ended
	May. 12, 2016	Apr. 30, 2016	Apr. 25, 2015	Jan. 25, 2014	Jul. 27, 2013	Apr. 28, 2012	Apr. 30, 2016	Apr. 25, 2015	Apr. 30, 2016	Jul. 25, 2015
Contingency [Line Items]
Loss Contingency, Expected Trial Commencement							2016-09
Purchase Commitments		$ 3,794.0					$ 3,794.0		$ 3,794.0	$ 4,078.0
Liability for purchase commitments		160.0					160.0		160.0	$ 156.0
Future compensation expense & contingent consideration, maximum		$ 400.0					$ 400.0		$ 400.0
Commitments and contingencies
Volume of channel partner financing		$ 6,400.0	$ 6,300.0				$ 19,800.0	$ 19,000.0
Balance of the channel partner financing subject to guarantees		1,000.0					1,000.0		$ 1,000.0	$ 1,200.0
Financing provided by third parties for leases and loans on which the Company has provided guarantees		18.0	22.0				57.0	87.0
Cost of Goods Sold		3,214.0	3,584.0				10,547.0	11,309.0
Brazilian Authority Claim Of Import Tax Evasion By Importer Tax Portion		233.0					233.0		233.0
Brazilian Authority Claim Of Import Tax Evasion By Importer Interest Portion		1,200.0					1,200.0		1,200.0
Brazilian Authority Claim Of Import Tax Evasion By Importer Penalties Portion		$ 1,100.0					1,100.0		1,100.0
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						$ 100.0
Ownership percentage as a result of investment					83.00%
Compensation expense related to acquisitions		$ 35.0	51.0				$ 136.0	$ 155.0	759.0
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		839.0					$ 839.0		839.0
Insieme Networks Inc | Partial First Milestone Payment [Member]
Contingency [Line Items]
Compensation expense related to acquisitions							375.0
Investments In Privately Held Companies
Contingency [Line Items]
Commitments and contingencies		199.0					199.0		199.0	205.0
Supplier Component Remediation Liability
Contingency [Line Items]
Commitments and contingencies		286.0		$ 63.0			$ 286.0		$ 286.0	$ 408.0
Cost of Goods Sold				$ 655.0
Supplier Component Remediation Liability | Cost of Goods, Product Line [Member]
Contingency [Line Items]
Product Warranty Accrual, Preexisting, Increase (Decrease)		$ 74.0	$ 164.0
Russia and the Commonwealth of Independent States [Member]
Contingency [Line Items]
Percentage of revenue, Percentage		2.00%
Backflip Software
Contingency [Line Items]
Loss Contingency, Institution Date							March 5, 2013
SRI International
Contingency [Line Items]
Loss Contingency, Institution Date							September 4, 2013
SSL Services, LLC
Contingency [Line Items]
Loss Contingency, Institution Date							March 25, 2015
Kangtega
Contingency [Line Items]
Loss Contingency, Institution Date							June 6, 2013
Subsequent Event | SRI International
Contingency [Line Items]
Loss Contingency, Damages Awarded, Value	$ 23.7