v3.26.1
Document and Entity Information - USD ($)
 12 Months Ended
Jun. 30, 2026
Aug. 31, 2026
Dec. 31, 2025
Cover [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Fiscal Year Focus 2026    
Document Fiscal Period Focus FY    
Document Period End Date Jun. 30, 2026    
Document Annual Report true    
Document Transition Report false    
Current Fiscal Year End Date --06-30    
Entity Registrant Name Grayscale Bitcoin Cash Trust (BCH)    
Entity Central Index Key 0001732409    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period true    
Entity Common Stock, Shares Outstanding   47,123,300  
Entity Public Float     $ 202,103,765
Entity Shell Company false    
Entity Filer Category Non-accelerated Filer    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity File Number 000-56308    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 82-6867376    
Entity Address, Address Line One 290 Harbor Drive, 4th Floor    
City Area Code 212    
Local Phone Number 668-1427    
Entity Address, City or Town Stamford    
Entity Address, Postal Zip Code 06902    
Entity Address, State or Province CT    
Title of 12(g) Security Grayscale Bitcoin Cash Trust (BCH) Shares    
Trading Symbol BCHG    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
ICFR Auditor Attestation Flag false    
Document Financial Statement Error Correction [Flag] false    
Documents Incorporated by Reference None    
Auditor Opinion [Text Block]

Opinion on the Financial Statements

    
Auditor Name KPMG LLP    
Auditor Location New York, New York    
Auditor Firm ID 185