v3.25.1
Cover Page - shares
 3 Months Ended
Mar. 31, 2025
Jun. 13, 2025
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Entity Registrant Name Churchill Capital Corp X/Cayman  
Entity Central Index Key 0002007825  
Entity File Number 001-42646  
Document Period End Date Mar. 31, 2025  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q1  
Entity Incorporation, State or Country Code E9  
Entity Tax Identification Number 86-1946291  
Entity Address, Address Line One 640 Fifth Avenue  
Entity Address, Address Line Two 14th Floor  
Entity Address, City or Town New York  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10019  
City Area Code 212  
Local Phone Number 380-7500  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company true  
Current Fiscal Year End Date --12-31  
Capital Units [Member]    
Document Information [Line Items]    
Title of 12(b) Security Units, each consisting of one Class A ordinary share and one-quarter of one redeemable warrant  
Trading Symbol CCCXU  
Security Exchange Name NASDAQ  
Common Class A [Member]    
Document Information [Line Items]    
Title of 12(b) Security Class A ordinary shares, par value $0.0001 per share  
Trading Symbol CCCX  
Security Exchange Name NASDAQ  
Entity Common Stock, Shares Outstanding   41,700,000
Warrant [Member]    
Document Information [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 CCCXW  
Security Exchange Name NASDAQ  
Common Class B [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   10,350,000