Stock Based Compensation - Summary Of Stock Options Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Number of Shares
Balance (in shares)	655,515
Exercised (in shares)	(187,504)
Expired (in shares)	(6,000)
Balance (in shares)	462,011	655,515
Exercisable (in shares)	462,011
Vested and expected to vest (in shares)	462,011
Weighted Average Exercise Price
Balance (in dollars per share)	$ 12.90
Exercised (in dollars per share)	10.80
Expired (in dollars per share)	0.50
Balance (in dollars per share)	13.90	$ 12.90
Exercisable (in dollars per share)	13.90
Vested and expected to vest (in dollars per share)	$ 13.90
Balance (in years)	4 years 7 days	4 years 10 months 28 days
Exercisable (in years)	4 years 7 days
Vested and expected to vest ( in years)	4 years 7 days
Aggregate Intrinsic Value, Balance	$ 20	$ 19
Aggregate Intrinsic Value, Exercisable	20
Aggregate Intrinsic Value, Vested and expected to vest	$ 20