v3.26.3
Document and Entity Information - shares
 9 Months Ended
Sep. 30, 2026
Oct. 29, 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 Sep. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q3  
Entity Registrant Name AA Mission Acquisition Corp. II  
Entity Central Index Key 0002075336  
Entity File Number 001-42886  
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 Tax Identification Number 00-0000000  
Entity Incorporation, State or Country Code E9  
Entity Address, Address Line One 21 Waterway Avenue  
Entity Address, Address Line Two STE 300 #9733  
Entity Address, City or Town The Woodlands  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 77380  
City Area Code (832)  
Local Phone Number 336-8887  
Units, each consisting of one Class A ordinary share and one-half of one warrant    
Document Information [Line Items]    
Title of 12(b) Security Units, each consisting of one Class A ordinary share and one-half of one warrant  
Trading Symbol YCY.U  
Security Exchange Name NYSE  
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 YCY  
Security Exchange Name NYSE  
Warrants, each whole warrant entitles the holder thereof to purchase one Class A ordinary share at a price of $11.50 per share    
Document Information [Line Items]    
Title of 12(b) Security Warrants, each whole warrant entitles the holder thereof to purchase one Class A ordinary share at a price of $11.50 per share  
Trading Symbol YCY.WS  
Security Exchange Name NYSE  
Class A Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   11,860,250
Class B Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   2,875,000