Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2020
Mar. 31, 2021
Cover [Abstract]    
Entity Registrant Name QS Energy, Inc.  
Entity Central Index Key 0001103795  
Document Type 10-K  
Document Period End Date Dec. 31, 2020  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
Is Entity's Reporting Status Current? Yes  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   325,381,243
Document Fiscal Period Focus FY  
Document Fiscal Year Focus 2020  
Entity Small Business true  
Entity Emerging Growth false  
Entity Interactive Data Current Yes  
Entity Incorporation State Country Code NV  
Entity File Number 000-29185  
Entity Well Known Seasoned Issuer No  
Entity Voluntary Filers No  
Entity Public Float $ 5,808,000  
Entity Shell Company false