v3.25.3
Cover - shares
 9 Months Ended
Sep. 30, 2025
Nov. 13, 2025
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, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q3  
Entity Information [Line Items]    
Entity Registrant Name INFLECTION POINT ACQUISITION CORP. III  
Entity Central Index Key 0002012318  
Entity File Number 001-42614  
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 Incorporation, Date of Incorporation Jan. 31, 2024  
Entity Contact Personnel [Line Items]    
Entity Address, Address Line One 167 Madison Avenue  
Entity Address, Address Line Two Suite 20 #1017  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10016  
Entity Phone Fax Numbers [Line Items]    
City Area Code (212)  
Local Phone Number 476-6908  
Units, each consisting of one Class A ordinary share, $0.0001 par value, and one right to receive one-tenth (1/10) of one Class A ordinary share    
Entity Listings [Line Items]    
Title of 12(b) Security Units, each consisting of one Class A ordinary share, $0.0001 par value, and one right to receive one-tenth (1/10) of one Class A ordinary share  
Trading Symbol IPCXU  
Security Exchange Name NASDAQ  
Class A ordinary shares, par value $0.0001 par value    
Entity Listings [Line Items]    
Title of 12(b) Security Class A ordinary shares, par value $0.0001 par value  
Trading Symbol IPCX  
Security Exchange Name NASDAQ  
Rights, each entitling the holder to receive one tenth (1/10) of one Class A ordinary share    
Entity Listings [Line Items]    
Title of 12(b) Security Rights, each entitling the holder to receive one tenth (1/10) of one Class A ordinary share  
Trading Symbol IPCXR  
Security Exchange Name NASDAQ  
Class A Ordinary Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   26,040,000
Class B Ordinary Shares    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   8,433,333