v3.26.1
Cover - USD ($)
9 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 Information [Line Items]      
Entity Registrant Name HIGHVIEW MERGER CORP.    
Entity Central Index Key 0002070602    
Entity File Number 001-42798    
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     $ 230,000,000
Entity Contact Personnel [Line Items]      
Entity Address, Address Line One 1615 South Congress Ave.    
Entity Address, Address Line Two Suite 103    
Entity Address, City or Town Delray Beach    
Entity Address, State or Province FL    
Entity Address, Postal Zip Code 33445    
Entity Phone Fax Numbers [Line Items]      
City Area Code 561    
Local Phone Number 826-6050    
Units, each consisting of one Class A ordinary share, $0.0001 par value, and one-half of one redeemable warrant      
Entity Listings [Line Items]      
Title of 12(b) Security Units, each consisting of one Class A ordinary share, $0.0001 par value, and one-half of one redeemable warrant    
Trading Symbol HVMCU    
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, $0.0001 par value    
Trading Symbol HVMC    
Security Exchange Name NASDAQ    
Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50 per share [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security Warrants, each whole warrant exercisable for one Class A ordinary share at an exercise price of $11.50 per share    
Trading Symbol HVMCW    
Security Exchange Name NASDAQ    
Class A Ordinary Shares      
Entity Listings [Line Items]      
Entity Common Stock, Shares Outstanding   23,660,000  
Class B Ordinary Shares      
Entity Listings [Line Items]      
Entity Common Stock, Shares Outstanding   5,750,000