v3.26.1
Cover - shares
 6 Months Ended
Jun. 30, 2026
Aug. 07, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Entity Registrant Name Invest Green Acquisition Corporation  
Entity Central Index Key 0002075068  
Entity File Number 001-42972  
Entity Tax Identification Number 00-0000000  
Entity Incorporation, State or Country Code E9  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company true  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Address, Address Line One 19215 SE 34th Street  
Entity Address, Address Line Two Suite # 106-159  
Entity Address, City or Town Camas  
Entity Address, State or Province WA  
Entity Address, Postal Zip Code 98607  
City Area Code 360  
Local Phone Number 409-7565  
Units, each consisting of one Class A Ordinary Share and one Right    
Document Information [Line Items]    
Title of 12(b) Security Units, each consisting of one Class A Ordinary Share and one Right  
Trading Symbol IGACU  
Security Exchange Name NASDAQ  
Class A Ordinary Shares, par value $0.0001 per share    
Document Information [Line Items]    
Title of 12(b) Security Class A Ordinary Shares, par value $0.0001 per share  
Trading Symbol IGAC  
Security Exchange Name NASDAQ  
Rights, each Right to acquire one-tenth (1/10) of one Class A Ordinary Share    
Document Information [Line Items]    
Title of 12(b) Security Rights, each Right to acquire one-tenth (1/10) of one Class A Ordinary Share  
Trading Symbol IGACR  
Security Exchange Name NASDAQ  
Class A Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   18,120,000
Class B Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   5,750,000