Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Jul. 31, 2020
Cover [Abstract]
Entity Interactive Data Current	Yes
Entity Address, Address Line One	333 Lakeside Drive
Title of 12(b) Security	Common Stock, par value, $0.001 per share
Entity Incorporation, State or Country Code	DE
Document Transition Report	false
Document Quarterly Report	true
Entity Registrant Name	GILEAD SCIENCES, INC.
Entity Central Index Key	0000882095
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2020
Entity File Number	0-19731
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business Company	false
Entity Common Stock, Shares Outstanding		1,253,724,370
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Tax Identification Number	94-3047598
Trading Symbol	GILD
Security Exchange Name	NASDAQ
Entity Address, City or Town	Foster City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94404
City Area Code	650
Local Phone Number	574-3000