Commitments and Contingencies (Additional Information) (Details) $ in Millions								3 Months Ended		6 Months Ended		12 Months Ended
	May 30, 2017 USD ($)	May 25, 2017 USD ($)	Mar. 14, 2017 USD ($)	Mar. 03, 2017 USD ($) patent	May 12, 2016 USD ($)	Jan. 15, 2016 claim patent	Sep. 04, 2013 patent	Jan. 27, 2018 USD ($)	Jan. 28, 2017 USD ($)	Jan. 27, 2018 USD ($)	Jan. 28, 2017 USD ($)	Jul. 30, 2016 USD ($)	Jul. 25, 2015 USD ($)	Jul. 26, 2014 USD ($)	Jul. 28, 2012 USD ($)	Jul. 29, 2017 USD ($)
Contingency [Line Items]
Liability for purchase commitments								$ 159.0		$ 159.0						$ 162.0
Future compensation expense & contingent consideration (up to)								246.0		246.0
Commitments and contingencies
Volume of channel partner financing								6,900.0	$ 6,300.0	13,600.0	$ 13,200.0
Balance of the channel partner financing subject to guarantees								1,000.0		1,000.0						1,000.0
Financing provided by third parties for leases and loans on which the Company has provided guarantees								12.0	30.0	26.0	36.0
Charge to product cost of sales								3,354.0	3,305.0	6,969.0	6,708.0
Adjustments for pre-existing warranties										(21.0)	(3.0)
Brazilian authority claim of import tax evasion by importer tax portion								257.0		257.0
Brazilian authority claim of import tax evasion by importer interest portion								1,600.0		1,600.0
Brazilian authority claim of import tax evasion by importer penalties portion								1,200.0		1,200.0
SRI International
Contingency [Line Items]
Damages awarded, value					$ 23.7
SRI International | Pending Litigation
Contingency [Line Items]
Damages awarded, value		$ 57.0
Number of allegedly infringed patents (patent) | patent							2
Percentage of royalty awarded		3.50%
Damages from Product Defects
Contingency [Line Items]
Charge for expected remediation									125.0
Patent Infringement | Sprint Communications Company, L.P. vs. Time Warner Cable, Inc. | Pending Litigation
Contingency [Line Items]
Number of patents found infringed (patent) | patent				5
Damages awarded, value			$ 139.8	$ 139.8
Percentage of post-judgment interest awarded			1.06%
Pre-judgment interest requested	$ 20.3
Patent Infringement | Huawei Technologies Co. Ltd. Vs. T-Mobile US, Inc. | Pending Litigation
Contingency [Line Items]
Number of patent infringement actions filed (claim) | claim						4
Number of allegedly infringed patents (patent) | patent						12
Patent Indemnification
Contingency [Line Items]
Legal and indemnification settlement										$ 127.0
Minimum
Contingency [Line Items]
Warranty period for products										90 days
Channel partners revolving short-term financing payment term										60 days
Maximum
Contingency [Line Items]
Warranty period for products										5 years
Channel partners revolving short-term financing payment term										90 days
End user lease and loan term										3 years
Insieme Networks Inc
Contingency [Line Items]
Variable interest entities investment															$ 100.0
Payments to acquire additional interest in subsidiaries											422.0
Compensation expense related to acquisitions									12.0		$ 32.0
Investments in privately held companies (impaired)
Contingency [Line Items]
Commitments and contingencies								215.0		$ 215.0						216.0
Supplier Component Remediation Liability
Contingency [Line Items]
Charge to product cost of sales														$ 655.0
Loss contingency accrual								$ 120.0		$ 120.0						$ 174.0
Supplier Component Remediation Liability | Cost of Goods, Product Line
Contingency [Line Items]
Adjustments for pre-existing warranties									$ (141.0)			$ 74.0	$ 164.0