Commitments and Contingencies - Additional Information (Details) $ in Millions							3 Months Ended		6 Months Ended		42 Months Ended
	Nov. 04, 2018 defendant	Feb. 13, 2018 patent	May 25, 2017 USD ($)	Mar. 03, 2017 USD ($) patent	May 12, 2016 USD ($)	Sep. 04, 2013 patent	Jan. 25, 2020 USD ($)	Jan. 26, 2019 USD ($)	Jan. 25, 2020 USD ($)	Jan. 26, 2019 USD ($)	Nov. 08, 2019 USD ($)	Jul. 27, 2019 USD ($)
Contingency [Line Items]
Liability for purchase commitments							$ 126.0		$ 126.0			$ 129.0
Future compensation expense & contingent consideration (up to)							370.0		370.0
Commitments and contingencies
Volume of channel partner financing							6,600.0	$ 7,300.0	14,200.0	$ 14,500.0
Balance of the channel partner financing subject to guarantees							1,300.0		1,300.0			1,400.0
Financing provided by third parties for leases and loans on which the Company has provided guarantees							1.0	$ 6.0	$ 6.0	9.0
SRI International | Pending Litigation
Contingency [Line Items]
Damages awarded, value			$ 57.0		$ 23.7
Number of allegedly infringed patents (patent) | patent						2
Percentage of royalty awarded			3.50%
Payment											$ 28.1
Oyster Optics | Pending Litigation
Contingency [Line Items]
Number remaining defendants, other than Cisco | defendant	1
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
Pre-judgment interest requested				$ 10.0
Patent Infringement | Centripetal | Pending Litigation
Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent		11
Number of allegedly infringed patents, petitioned (patent) | patent		9
Number of allegedly infringed patents, unpatentable (patent) | patent		3
Patent Infringement, IPR Proceedings | Centripetal | Pending Litigation
Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent		6
Patent Infringement, Patent Trial and Appeal Board | Centripetal | Pending Litigation
Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent		4
Patent Infringement, Not Subject to IPR Proceedings | Centripetal | Pending Litigation
Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent		5
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
Investments in privately held companies (impaired)
Contingency [Line Items]
Commitments and contingencies							291.0		$ 291.0			$ 326.0
Inventories
Contingency [Line Items]
Purchase commitment									4,500.0	$ 5,000.0
Tax Year 2003 - 2007 | Brazilian tax authority
Contingency [Line Items]
Penalty and interest asserted by the Brazilian federal tax authorities							$ 800.0		800.0
Income tax examination, tax									200.0
Income tax examination, interest									900.0
Income tax examination, penalties									$ 500.0