Cover Page - shares shares in Millions	6 Months Ended
	Jun. 29, 2025	Jul. 25, 2025
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 29, 2025
Document Transition Report	false
Entity File Number	001-35406
Entity Registrant Name	Illumina, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0804655
Entity Address, Address Line One	5200 Illumina Way
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92122
City Area Code	858
Local Phone Number	202-4500
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	ILMN
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		153.7
Entity Central Index Key	0001110803
Current Fiscal Year End Date	--12-28
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q2
Amendment Flag	false