v3.26.1
Cover
 12 Months Ended
Dec. 31, 2025
shares
Entity Addresses [Line Items]  
Document Type 20-F
Amendment Flag false
Document Registration Statement false
Document Annual Report true
Document Transition Report false
Document Shell Company Report false
Document Period End Date Dec. 31, 2025
Document Fiscal Period Focus FY
Document Fiscal Year Focus 2025
Current Fiscal Year End Date --12-31
Entity File Number 001-43114
Entity Registrant Name AGI INC
Entity Central Index Key 0002081206
Entity Incorporation, State or Country Code E9
Entity Address, Address Line One Rua Sergio Fernandes Borges Soares
Entity Address, Address Line Two 1000, Prédio E1
Entity Address, City or Town Campinas
Entity Address, Country BR
Entity Address, Postal Zip Code 13054-709
Title of 12(b) Security Class A common shares, par value US$0.00005 per share
Trading Symbol AGBK
Security Exchange Name NYSE
Entity Well-known Seasoned Issuer No
Entity Voluntary Filers No
Entity Current Reporting Status Yes
Entity Interactive Data Current Yes
Entity Filer Category Non-accelerated Filer
Entity Emerging Growth Company false
Document Accounting Standard International Financial Reporting Standards
Entity Shell Company false
Document Financial Statement Error Correction [Flag] false
ICFR Auditor Attestation Flag false
Auditor Firm ID 1448
Auditor Name Ernst & Young Auditores Independentes S/S Ltda.
Auditor Location Brasília, Brazil
Class A common shares  
Entity Addresses [Line Items]  
Entity Common Stock, Shares Outstanding 58,700,711
Class B common shares  
Entity Addresses [Line Items]  
Entity Common Stock, Shares Outstanding 101,229,359
Business Contact [Member]  
Entity Addresses [Line Items]  
Entity Address, Address Line One Rua Sergio Fernandes Borges Soares
Entity Address, Address Line Two 1000, Prédio E1
Entity Address, City or Town Campinas
Entity Address, Country BR
Entity Address, Postal Zip Code 13054-709
City Area Code 55 (19)
Local Phone Number 3031-4000
Contact Personnel Name Marcello Winnik Dubeux