v3.26.3
Document And Entity Information - shares
 9 Months Ended
Sep. 30, 2026
Nov. 09, 2026
Document Information Line Items    
Entity Central Index Key 0002085408  
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2026  
Document Fiscal Year Focus 2026  
Document Transition Report false  
Entity File Number 001-42986  
Entity Registrant Name GENERAL PURPOSE ACQUISITION CORP.  
Entity Incorporation, State or Country Code E9  
Entity Tax Identification Number 00-0000000  
Entity Address, Address Line One 59 Front Street  
Entity Address, City or Town Millbrook  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 12545  
City Area Code 845  
Local Phone Number 677-4650  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company true  
Amendment Flag false  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --12-31  
Units [Member]    
Document Information Line Items    
Title of 12(b) Security Units, each consisting of one Class A ordinary share, $0.0001 par value, and one-half of one redeemable warrant  
Trading Symbol GPACU  
Security Exchange Name NASDAQ  
Class A Ordinary Shares [Member]    
Document Information Line Items    
Title of 12(b) Security Class A ordinary shares, $0.0001 par value  
Trading Symbol GPAC  
Security Exchange Name NASDAQ  
Entity Common Stock, Shares Outstanding   23,660,000
Redeemable Warrants [Member]    
Document Information Line Items    
Title of 12(b) Security Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50 per share  
Trading Symbol GPACW  
Security Exchange Name NASDAQ  
Class B Ordinary Shares [Member]    
Document Information Line Items    
Entity Common Stock, Shares Outstanding   5,750,000