Employee Benefit Plans - Shares Available For Grant (Details) - Equity Incentive Plan 2015 - shares shares in Millions	1 Months Ended		12 Months Ended
	May 31, 2019	May 31, 2017	Dec. 31, 2019
Shares Available For Grant
Balance as of beginning of period (in shares)			21.9
Additional shares authorized (in shares)	3.7	23.0	3.7
RSUs and PSAs granted (in shares)			(15.5)
RSUs and PSAs canceled (in shares)			6.5
Balance as of end of period (in shares)			16.6