v3.26.1
Cover
Apr. 29, 2026
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Apr. 29, 2026
Entity File Number 001-42997
Entity Registrant Name Twenty One Capital, Inc.
Entity Central Index Key 0002070457
Entity Tax Identification Number 39-2506682
Entity Incorporation, State or Country Code TX
Entity Address, Address Line One 111 Congress Avenue
Entity Address, Address Line Two Suite 500
Entity Address, City or Town Austin
Entity Address, State or Province TX
Entity Address, Postal Zip Code 78701
City Area Code 206
Local Phone Number 552-9859
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Class A common stock, par value $0.01 per share
Trading Symbol XXI
Security Exchange Name NYSE
Entity Emerging Growth Company true
Elected Not To Use the Extended Transition Period false