Document and Entity Information (USD $) In Billions, except Share data, unless otherwise specified	3 Months Ended
	Apr. 01, 2012	Apr. 13, 2012	Jul. 03, 2011
Document and Entity Information [Abstract]
Entity Registrant Name	Illumina Inc
Entity Central Index Key	0001110803
Document Type	10-Q
Document Period End Date	Apr. 01, 2012
Amendment Flag	false
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-30
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 9.3
Entity Common Stock, Shares Outstanding		123,448,010