v3.26.1
Stock Transactions - Changes in Shares of Class A Common Stock Outstanding (Details) - shares
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Share issuances:        
Treasury stock repurchases (in shares)     10,452,000 20,408,000
Limited Partnership        
Share issuances:        
Number of units redeemed and cancelled for exchange (in shares) (400,000) (400,000) (600,000) 700,000
Class A Common Stock        
Increase (Decrease) in Stockholders' Equity [Roll Forward]        
Shares outstanding at beginning of period (in shares) 369,430,000 378,134,000 363,175,000 374,297,000
Share issuances:        
Contingent share obligations (in shares) 410,000 376,000 519,000 617,000
Vesting of RSUs (in shares) 2,016,000 2,254,000 5,928,000 7,078,000
Acquisitions (in shares) 0 268,257 374,872 641,653
Other issuances of BGC Class A common stock (in shares) 1,671,000 2,487,000 3,800,000 4,340,000
Restricted stock forfeitures (in shares) (88,123) (101,852) (112,211) (372,504)
Treasury stock repurchases (in shares) (10,206,000) (17,224,000)    
Shares outstanding at end of period (in shares) 363,233,000 366,193,000 363,233,000 366,193,000
Conversion, shares issued (in shares) 400,000 400,000 500,000 600,000