v3.26.1
NET EARNINGS PER SHARE - Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Numerator:          
Net loss $ (596,520) $ (56,917) $ (30,489) $ (733,113) $ (87,406)
Less: Net loss attributable to Quantinuum (Cayman) prior to the Transactions (110,087)     (246,680)  
Less: Net loss attributable to the non-controlling interest (421,015)     (421,015)  
Net loss attributable to Quantinuum Inc. $ (65,418)     $ (65,418)  
Denominator:          
Weighted average shares used in computing net loss per share attributable to Class A common stockholders - basic [1] 33,914,995     33,914,995  
Weighted average shares used in computing net loss per share attributable to Class A common stockholders - diluted [1] 33,914,995     33,914,995  
Net loss per share attributable to common Class A shareholders - basic [1] $ (1.93)     $ (1.93)  
Net loss per share attributable to Class A common shareholders - diluted [1] $ (1.93)     $ (1.93)  
[1] Represents net loss per share of Class A common stock and weighted-average shares of Class A common stock for the period during the Transactions through June 30, 2026, which is the period effective with and following the Transactions as defined in Note 1 — Description of Organization. Refer to Note 14 — Net Earnings Per Share for additional details.