CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Investments and receivables at fair value	$ 3,452.3	$ 2,271.4
Class A
Common stock, nominal value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	171,378,773	171,917,370
Common stock, outstanding (in shares)	171,378,773	171,917,370
Class B
Common stock, nominal value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	12,988,658	12,994,000
Common stock, outstanding (in shares)	12,988,658	12,994,000
Class C
Common stock, nominal value (in dollars per share)	$ 0.01	$ 0.01
Common stock, issued (in shares)	218,384,732	274,436,585
Common stock, outstanding (in shares)	218,384,732	274,436,585