XML 13 R1.htm IDEA: XBRL DOCUMENT v3.25.4
Cover - USD ($)
 12 Months Ended
Dec. 31, 2025
Feb. 26, 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 true    
Amendment Flag false    
Document Period End Date Dec. 31, 2025    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Documents Incorporated by Reference [Text Block] None    
Entity Information [Line Items]      
Entity Registrant Name ARK 21Shares Bitcoin ETF    
Entity Central Index Key 0001869699    
Entity File Number 001-41910    
Entity Tax Identification Number 87-6497023    
Entity Incorporation, State or Country Code DE    
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 false    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Public Float     $ 5,034,361,000
Entity Incorporation, Date of Incorporation Jun. 22, 2021    
Entity Contact Personnel [Line Items]      
Entity Address, Address Line One 477 Madison Avenue    
Entity Address, Address Line Two 6th Floor    
Entity Address, City or Town New York    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 10022    
Entity Phone Fax Numbers [Line Items]      
City Area Code (646)    
Local Phone Number 370-6016    
Entity Listings [Line Items]      
Title of 12(b) Security Shares of Beneficial Interests of ARK 21Shares Bitcoin ETF    
Trading Symbol ARKB    
Security Exchange Name CboeBZX    
Entity Common Stock, Shares Outstanding   107,550,000