XML 15 R1.htm IDEA: XBRL DOCUMENT v3.22.2.2
Cover - shares
 9 Months Ended
Jun. 30, 2022
Aug. 10, 2022
Entity Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2022  
Document Transition Report false  
Entity File Number 001-40978  
Entity Registrant Name Fluence Energy, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 87-1304612  
Entity Address, Address Line One 4601 Fairfax Drive  
Entity Address, Address Line Two Suite 600  
Entity Address, City or Town Arlington  
Entity Address, State or Province VA  
Entity Address, Postal Zip Code 22203  
City Area Code (833)  
Local Phone Number 358-3623  
Title of 12(b) Security Class A common stock, $0.00001 par value  
Trading Symbol FLNC  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Central Index Key 0001868941  
Current Fiscal Year End Date --09-30  
Document Fiscal Year Focus 2022  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Class A common stock    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding   114,306,316
Common Class B-1    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding   58,586,695