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Stockholders' Equity - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Feb. 06, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant (in shares)	2,839,430		2,839,430
Authorized Amount					$ 300
Repurchase of common stock (in shares)	392,700	434,766	1,175,609	594,799
Repurchase of common stock			$ 62
Amount available for further repurchases under stock repurchase program	$ 313		$ 313
Time-Based Restricted Stock Units and Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			4 years
Performance-Based Restricted Stock Units and Restricted Stock Awards [Member] \| Tranche 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)			1 year
Vesting percentage (as a percent)			50.00%
Minimum \| Time-Based Restricted Stock Units and Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent			0.00%
Maximum \| Time-Based Restricted Stock Units and Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent			200.00%