v3.26.1
Cover - shares
6 Months Ended
Jun. 30, 2026
Aug. 03, 2026
Document Information [Line Items]    
Entity Central Index Key 0001869699  
Document Type 10-Q  
Document Quarterly Report true  
Current Fiscal Year End Date --12-31  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Transition Report false  
Entity File Number 001-41910  
Entity Registrant Name ARK 21Shares Bitcoin ETF  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 87-6497023  
Entity Address, Address Line One 158 W. 27th Street  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10001  
City Area Code (646)  
Local Phone Number 370-6016  
Title of 12(b) Security Shares of Beneficial Interest of ARK 21Shares Bitcoin ETF  
Trading Symbol ARKB  
Security Exchange Name CboeBZX  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   101,190,000
Amendment Flag false  
Document Fiscal Period Focus Q2