XML 15 R1.htm IDEA: XBRL DOCUMENT v3.26.1
Cover - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Mar. 18, 2026
Jun. 30, 2025
Document Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Transition Report false    
Document Financial Statement Error Correction [Flag] false    
Entity Interactive Data Current Yes    
ICFR Auditor Attestation Flag false    
Amendment Flag false    
Document Period End Date Dec. 31, 2025    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Entity Information [Line Items]      
Entity Registrant Name ARTIUS II ACQUISITION INC.    
Entity Central Index Key 0002034334    
Entity File Number 1-42521    
Entity Tax Identification Number 98-1802901    
Entity Incorporation, State or Country Code E9    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
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 Public Float     $ 222.6
Entity Contact Personnel [Line Items]      
Entity Address, Address Line One 3 Columbus Circle    
Entity Address, Address Line Two Suite 1609    
Entity Address, City or Town New York    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 10019    
Entity Phone Fax Numbers [Line Items]      
City Area Code 212    
Local Phone Number 309-7668    
Units [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security Units, each consisting of one Class A ordinary share, $0.0001 par value, including one attached contingent right, and one right to receive one-tenth    
Trading Symbol AACBU    
Security Exchange Name NASDAQ    
Common Class A [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security Class A ordinary shares, par value $0.0001 per share, including one attached contingent right    
Trading Symbol AACB    
Security Exchange Name NASDAQ    
Rights [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security Rights, each right entitling the holder to receive one-tenth of one Class A ordinary share    
Trading Symbol AACBR    
Security Exchange Name NASDAQ    
Class A Ordinary Shares [Member]      
Entity Listings [Line Items]      
Entity Common Stock, Shares Outstanding   22,175,000  
Class B Ordinary Shares [Member]      
Entity Listings [Line Items]      
Entity Common Stock, Shares Outstanding   5,500,000