v3.26.1
NON-CONTROLLING INTERESTS - Summary of the Effect Of Changes in Ownership on the Company's Equity (Details) - USD ($)
$ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Noncontrolling Interest [Line Items]            
Net loss   $ (596,520) $ (56,917) $ (30,489) $ (733,113) $ (87,406)
Accumulated other comprehensive (loss) income:            
Foreign exchange translation adjustment, net of tax of zero   $ (4,296) 51,318 25,707 $ (15,711) $ 77,025
Accumulated other comprehensive (loss)/income            
Accumulated other comprehensive (loss) income:            
Foreign exchange translation adjustment, net of tax of zero     $ 51,318 $ 25,707    
Quantinuum Inc.            
Noncontrolling Interest [Line Items]            
Net loss $ (65,418)          
Additional paid-in capital:            
Total effect of changes in ownership interest on equity attributable to Quantinuum Inc. (9,033)          
Quantinuum Inc. | Accumulated other comprehensive (loss)/income            
Accumulated other comprehensive (loss) income:            
Foreign exchange translation adjustment, net of tax of zero (1,878)          
Non-controlling interest adjustment for changes in proportionate ownership in Quantinuum Holdings 9          
Quantinuum Inc. | Additional paid-in-capital            
Accumulated other comprehensive (loss) income:            
Non-controlling interest adjustment for changes in proportionate ownership in Quantinuum Holdings 14,716          
Additional paid-in capital:            
Stock-based compensation 316,777          
Increase (decrease) as a result of non-controlling interest adjustment for stock-based compensation $ (273,239)