v3.10.0.1
Document and Entity Information Document - USD ($)
shares in Millions, $ in Billions
12 Months Ended
Dec. 30, 2018
Feb. 08, 2019
Jul. 01, 2018
Document and Entity Information [Abstract]      
Entity Registrant Name Illumina Inc    
Entity Central Index Key 0001110803    
Current Fiscal Year End Date --12-30    
Entity Filer Category Large Accelerated Filer    
Document Type 10-K    
Document Period End Date Dec. 30, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   147  
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 35.9
Entity Emerging Growth Company false    
Entity Small Business false    
Entity Shell Company false