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, 2024	Nov. 30, 2024	Oct. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share issuances:
Redemptions/exchanges of limited partnership interests (in shares)												29,118,664	30,998,136
Restricted stock awards (in shares)											0	38,610,233
Restricted stock forfeitures (in shares)											(300,000)	(1,400,000)
Treasury stock repurchases (in shares)	0	0	(6,369,000)	(7,893,000)	(10,688,000)	(11,250,000)	(5,473,000)	(8,087,000)	(9,814,000)	(846,000)	(36,200,000)	(24,220,000)
Contingent restricted stock awards (in shares)											6,700,000
Limited Partnership
Share issuances:
Common stock, shares issued (in shares)											1,800,000	400,000
Number of units redeemed and cancelled for exchange (in shares)												26,400,000
Class A Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares outstanding at beginning of period (in shares)						390,095,000				325,858,000	390,095,000	325,858,000
Share issuances:
Redemptions/exchanges of limited partnership interests (in shares)											1,756,000	30,754,000
Vesting of RSUs (in shares)											9,996,000	13,009,000
Acquisitions (in shares)											1,062,000	4,566,000
Other issuances of BGC Class A common stock (in shares)											9,028,000	2,946,000
Restricted stock forfeitures (in shares)											(1,439,575)	(1,428,363)
Treasury stock repurchases (in shares)											(31,573,031)	(23,250,551)	(27,086,884)
Shares outstanding at end of period (in shares)	374,297,000						390,095,000				374,297,000	390,095,000	325,858,000
Common stock, shares issued (in shares)											1,800,000	20,500,000