Commitments and Contingencies - Additional Information (Details) $ in Millions									12 Months Ended			50 Months Ended
	Apr. 30, 2020 patent	Apr. 01, 2020 USD ($)	Feb. 13, 2018 patent	May 25, 2017 USD ($)	Mar. 03, 2017 USD ($) patent	Jan. 06, 2017 patent	May 12, 2016 USD ($)	Sep. 04, 2013 patent	Jul. 25, 2020 USD ($)	Jul. 27, 2019 USD ($)	Jul. 28, 2018 USD ($)	Jul. 25, 2020 USD ($)	Jan. 25, 2020 USD ($)
Site Contingency [Line Items]
Provision for purchase commitment liability									$ 139.0	$ 95.0	$ 105.0
Future compensation expense & contingent consideration (up to)									271.0			$ 271.0
Commitments and contingencies
Volume of channel partner financing									26,900.0	29,600.0	28,200.0
Balance of the channel partner financing subject to guarantees									1,100.0	1,400.0		1,100.0
Financing provided by third parties for leases and loans related to end users on which the Company has provided guarantees									9.0	14.0	35.0
Brazilian Tax Authority | Tax years 2003 through 2007
Site Contingency [Line Items]
Penalty and interest asserted by the Brazilian federal tax authorities													$ 800.0
Brazilian authority claim of import tax evasion by importer tax portion									155.0
Brazilian authority claim of import tax evasion by importer interest portion									756.0
Brazilian authority claim of import tax evasion by importer penalties portion									$ 383.0
SRI International
Site Contingency [Line Items]
Damages awarded, value							$ 23.7
Pending Litigation | SRI International
Site Contingency [Line Items]
Damages awarded, value		$ 8.0		$ 57.0
Number of allegedly infringed patents (patent) | patent								2
Percentage of royalty awarded				3.50%
Damages paid, value												28.1
Patent Infringement | Pending Litigation | Sprint Communications Company L.P. vs. Time Warner Cable Inc.
Site Contingency [Line Items]
Number of patents found infringed (patent) | patent					5
Damages awarded, value					$ 139.8
Pre and Post judgment interest awarded					$ 10.0
Patent Infringement | Pending Litigation | Centripetal
Site Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent			11
Number of allegedly infringed patents, petitioned (patent) | patent			9
Patent Infringement | Pending Litigation | Finjan
Site Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent						5
Number of allegedly infringed patents, expired (patent) | patent						4
Patent Indemnification
Site Contingency [Line Items]
Legal and indemnification settlement											$ 127.0
Patent Infringement, IPR Proceedings | Pending Litigation | Centripetal
Site Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent			6
Patent Infringement, Patent Trial and Appeal Board | Pending Litigation | Centripetal
Site Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent			7
Patent Infringement, Not subject to IPR Proceedings | Pending Litigation | Centripetal
Site Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent			5
Patent Infringement, Not subject to IPR Proceedings and IPR Declined | Pending Litigation | Centripetal
Site Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent			3
Patent Infringement, European patents | Pending Litigation | Centripetal
Site Contingency [Line Items]
Number of allegedly infringed patents (patent) | patent	3
Minimum
Site Contingency [Line Items]
Warranty period for products									90 days
Channel partners revolving short-term financing payment term									60 days
Maximum
Site 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
Non-marketable equity securities and equity method investments
Site Contingency [Line Items]
Commitments and contingencies									$ 300.0			300.0
Inventory
Site Contingency [Line Items]
Purchase commitment									$ 4,400.0	5,000.0
COVID-19
Site Contingency [Line Items]
Increase in certain channel partners revolving short-term financing payment term									30 days
Inventory
Site Contingency [Line Items]
Liability for purchase commitments									$ 141.0	$ 129.0		$ 141.0