v3.25.1
Document - shares
 3 Months Ended
Mar. 31, 2025
Apr. 25, 2025
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2025  
Document Transition Report false  
Entity File Number 001-33156  
Entity Registrant Name First Solar, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 20-4623678  
Entity Address, Address Line One 350 West Washington Street, Suite 600  
Entity Address, City or Town Tempe  
Entity Address, State or Province AZ  
Entity Address, Postal Zip Code 85288  
City Area Code 602  
Local Phone Number 414-9300  
Title of 12(b) Security Common stock, $0.001 par value  
Trading Symbol FSLR  
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   107,244,479
Entity Central Index Key 0001274494  
Amendment Flag false  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q1  
Current Fiscal Year End Date --03-31