Condensed Consolidated Statements of Financial Condition (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares issued (in shares)	426,015,000	373,545,000
Common stock, shares outstanding (in shares)	333,408,000	323,018,000
Treasury stock, at cost (in shares)	92,607,000	50,527,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	45,884,000	45,884,000
Common stock, shares outstanding (in shares)	45,884,000	45,884,000