Stock Transactions and Unit Redemptions - Schedule of Changes in Shares of Class A Common Stock Outstanding (Details) - shares	1 Months Ended						3 Months Ended						12 Months Ended
	Dec. 31, 2025	Nov. 30, 2025	Oct. 31, 2025	Dec. 31, 2024	Nov. 30, 2024	Oct. 31, 2024	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Share issuances:
Redemptions/exchanges of limited partnership interests and contingent share obligations (in shares)															29,118,664
Acquisitions (in shares)														1,061,665	405,801
Restricted stock forfeitures (in shares)													(100,000)	(300,000)
Treasury stock repurchases (in shares)	0	(1,191,000)	(6,200,000)	0	0	(6,369,000)	(4,239,000)	(17,224,000)	(3,184,000)	(7,893,000)	(10,688,000)	(11,250,000)	(32,038,000)	(36,200,000)
Limited Partnership
Share issuances:
Common stock, shares issued (in shares)													1,000,000.0	1,800,000
Class A Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at beginning of period (in shares)									374,297,000			390,095,000	374,297,000	390,095,000
Share issuances:
Redemptions/exchanges of limited partnership interests and contingent share obligations (in shares)													922,000	1,756,000
Vesting of RSUs (in shares)													9,873,000	9,996,000
Acquisitions (in shares)													694,000	1,062,000
Other issuances of BGC Class A common stock (in shares)													9,895,000	9,028,000
Restricted stock forfeitures (in shares)													(468,223)	(1,439,575)
Treasury stock repurchases (in shares)													(30,197,095)	(31,573,031)	(23,250,551)
Shares outstanding at end of period (in shares)	363,175,000			374,297,000									363,175,000	374,297,000	390,095,000
Common stock, shares issued (in shares)													900,000	1,800,000