Equity-Based Compensation Plans - Summary of Stock Award Activity (Details)	6 Months Ended
	Jun. 30, 2021 $ / shares shares
Number of Shares of Class A Common Stock (#)
Outstanding at beginning of period (in shares)	6,133,000
Vested (in shares)	(1,816,000)
Forfeited (in shares)	(824,000)
Outstanding at end of period (in shares)	7,259,000
RSUs
Number of Shares of Class A Common Stock (#)
Granted (in shares)	3,355,000
Outstanding at end of period (in shares)	6,483,000
Weighted-average grant-date fair value per share (in dollars per share) | $ / shares	$ 77.18
TSR-based PSUs
Number of Shares of Class A Common Stock (#)
Granted (in shares)	411,000
Outstanding at end of period (in shares)	612,000
Weighted-average grant-date fair value per share (in dollars per share) | $ / shares	$ 106.66
Financial-based PSUs granted for accounting purposes
Number of Shares of Class A Common Stock (#)
Outstanding at end of period (in shares)	83,000
Weighted-average grant-date fair value per share (in dollars per share) | $ / shares	$ 78.62
Financial-based PSUs not yet granted for accounting purposes
Number of Shares of Class A Common Stock (#)
Outstanding at end of period (in shares)	81,000