v3.26.1
Net Income (Loss) Per Share Attributable to Compass, Inc. - Schedule of Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Jan. 09, 2026
Numerator:          
Net income (loss) attributable to Compass, Inc. $ 92 $ 39 $ 114 $ (12)  
Interest expense on the 0.25% Convertible Senior Notes 2 0 4 0  
Net income used in computing diluted net income per share of common stock $ 94 $ 39 $ 118 $ (12)  
Denominator:          
Weighted-average shares used in computing net income (loss) per share attributable to Compass, Inc., basic (in shares) 758,064,181 560,307,749 746,273,149 555,255,128  
Net income (loss) per share attributable to Compass, Inc., basic (in dollars per share) $ 0.12 $ 0.07 $ 0.15 $ (0.02)  
Weighted-average effect of dilutive securities:          
Shares issuable upon conversion of the 0.25% Convertible Senior Notes due 2031 (in shares) 62,562,600 0 60,129,610 0  
Incremental common stock to be issued in connection with the CIRE Share Consideration (in shares) 0 13,107,194 0 0  
Weighted-average number of shares outstanding used to compute net income (loss) per share attributable to Compass, Inc., diluted (in shares) 842,377,292 591,370,687 832,950,962 555,255,128  
Net income (loss) per share attributable to Compass, Inc., diluted (in dollars per share) $ 0.11 $ 0.07 $ 0.14 $ (0.02)  
Christie's International Real Estate          
Denominator:          
Weighted-average shares used in computing net income (loss) per share attributable to Compass, Inc., basic (in shares)   38,500,000   38,500,000  
Weighted-average effect of dilutive securities:          
Weighted-average number of shares outstanding used to compute net income (loss) per share attributable to Compass, Inc., diluted (in shares)   13,100,000      
Stock options          
Weighted-average effect of dilutive securities:          
Weighted-average effect of diluted securities (in shares) 7,253,981 5,806,554 9,169,210 0  
RSUs          
Weighted-average effect of dilutive securities:          
Weighted-average effect of diluted securities (in shares) 14,496,530 12,077,480 17,350,835 0  
Employee Stock Purchase Plan          
Weighted-average effect of dilutive securities:          
Weighted-average effect of diluted securities (in shares) 0 16,016 28,158 0  
Unvested common stock          
Weighted-average effect of dilutive securities:          
Weighted-average effect of diluted securities (in shares) 0 55,694 0  
0.25% Convertible Senior Notes | Convertible Debt          
Weighted-average effect of dilutive securities:          
Debt instrument, interest rate 0.25%   0.25%   0.25%