Organization and Basis of Presentation (Details) - USD ($)				3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 02, 2023	Jul. 01, 2023	Jun. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Total number of shares (in shares)				0
Conversion of stock, shares converted (in shares)		64,000,000
Minimum number of shares required to be issued (in shares)		75,000,000
Stock Purchased On 6/30/2023
Related Party Transaction [Line Items]
Conversion of stock, shares converted (in shares)		5,700,000
Class A Common Stock
Related Party Transaction [Line Items]
Shares granted in period (in shares)		600,000,000
Issuance of common stock (in shares)				55,348		234,931
Common stock, shares authorized (in shares)		1,500,000,000		1,500,000,000		1,500,000,000		1,500,000,000
Common stock, par value (in dollars per share)				$ 0.01		$ 0.01		$ 0.01
Class A Common Stock | BGC Parnters
Related Party Transaction [Line Items]
Common stock, par value (in dollars per share)		$ 0.01
Class A Common Stock | BGC Group
Related Party Transaction [Line Items]
Common stock, par value (in dollars per share)		$ 0.01
Class B Common Stock
Related Party Transaction [Line Items]
Issuance of common stock (in shares)	15,800,000	64,000,000		64,000,000		64,000,000		0
Common stock, shares authorized (in shares)		300,000,000		300,000,000		300,000,000		150,000,000
Common stock, par value (in dollars per share)				$ 0.01		$ 0.01		$ 0.01
Class B Common Stock | BGC Parnters
Related Party Transaction [Line Items]
Common stock, par value (in dollars per share)		$ 0.01
Class B Common Stock | BGC Group
Related Party Transaction [Line Items]
Common stock, par value (in dollars per share)		$ 0.01
Related Party
Related Party Transaction [Line Items]
Issuance of common stock (in shares)				0	0	0	0
Non-exchangeable Limited Partnership Interests
Related Party Transaction [Line Items]
Share-based payment arrangement, expense				$ 60,900,000
Exchangeable Limited Partnership Units | Related Party
Related Party Transaction [Line Items]
Shares redeemed in period (in shares)				1,500,000
Share-Based Payment Arrangement | Related Party | Class A Common Stock
Related Party Transaction [Line Items]
Shares granted in period (in shares)				1,000,000
Restricted Stock Units (RSUs)
Related Party Transaction [Line Items]
Shares granted in period (in shares)		25,300,000
Share-based payment arrangement, decrease for tax withholding obligation		$ 74,000,000	$ 49,200,000
Corporate conversion, exchange ratio (in shares)				1		1
Restricted Stock Units (RSUs) | Related Party
Related Party Transaction [Line Items]
Shares granted in period (in shares)				16,900,000
Non-exchangeable FPUs | Related Party
Related Party Transaction [Line Items]
Shares redeemed in period (in shares)				5,600,000
FPU | Related Party
Related Party Transaction [Line Items]
Shares redeemed in period (in shares)				5,425,209
Shares exchanged in period (in shares)				324,223
Cantor Units | Related Party
Related Party Transaction [Line Items]
Shares redeemed in period (in shares)				324,223
Cantor Units | Related Party | Cantor
Related Party Transaction [Line Items]
Shares redeemed in period (in shares)				5,425,209
Shares redeemed in period, value				$ 9,715,772
FPU & Cantor Units | Related Party
Related Party Transaction [Line Items]
Shares redeemed in period, value				598,712
Restricted Shares
Related Party Transaction [Line Items]
Share-based payment arrangement, expense				$ 17,400,000		$ 17,400,000
Restricted Shares | Maximum
Related Party Transaction [Line Items]
Shares granted in period (in shares)		38,600,000