Related Party Transactions - Other Agreements with Cantor (Details) - USD ($)		3 Months Ended		9 Months Ended
	Jul. 01, 2023	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Aug. 31, 2013
Related Party Transaction [Line Items]
Repurchase agreements		$ 0		$ 0		$ 0
Reverse repurchase agreements		0		0		0
Commissions		573,159,000	$ 407,095,000	1,667,366,000	$ 1,217,348,000
Investment in asset-backed commercial paper program		$ 0		$ 0		0
Conversion of stock, shares converted (in shares)	64,000,000
Minimum number of shares required to be issued (in shares)	75,000,000
Class A Common Stock | Cantor
Related Party Transaction [Line Items]
Investment owned, balance (in shares)		0		0
Class A Common Stock | CFGM
Related Party Transaction [Line Items]
Investment owned, balance (in shares)		0		0
Class B Common Stock | Cantor
Related Party Transaction [Line Items]
Investment owned, balance (in shares)		93,300,000		93,300,000
Class B Common Stock | CFGM
Related Party Transaction [Line Items]
Investment owned, balance (in shares)		3,000,000.0		3,000,000.0
Related Party
Related Party Transaction [Line Items]
Repurchase agreements		$ 0		$ 0		0
Reverse repurchase agreements		0		0		$ 0
Recognition of share of FX gains (losses)		(100,000)	(5,200,000)	(3,000,000.0)	(6,600,000)
Commissions		$ 100,000	$ 100,000	$ 300,000	$ 300,000
Investment authorization in asset-backed commercial paper program							$ 350,000,000.0