v3.26.1
Cover - USD ($)
 12 Months Ended
Dec. 31, 2025
Mar. 27, 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 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 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     $ 260,252,600
Entity Address, Address Line One 167 Madison Avenue    
Entity Address, Address Line Two Ste. 205 #1017    
Entity Address, City or Town New York    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 10016    
City Area Code (212)    
Local Phone Number 295-5830    
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      
Document Information [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, $0.0001 par value      
Document Information [Line Items]      
Title of 12(b) Security Class A Ordinary Shares, $0.0001 par value    
Trading Symbol ICPX    
Security Exchange Name NASDAQ    
Rights, each entitling the holder to receive one tenth (1/10) of one Class A ordinary share      
Document Information [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 ICPXR    
Security Exchange Name NASDAQ    
Class A Ordinary Shares      
Document Information [Line Items]      
Entity Common Stock, Shares Outstanding   26,040,000  
Class B Ordinary Shares      
Document Information [Line Items]      
Entity Common Stock, Shares Outstanding   8,433,333