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Stockholders' Equity - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Feb. 06, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchase Program, Authorized Amount			$ 300
Number of shares available for grant (in shares)	14,000,000
Repurchase of common stock (in shares)	782,909
Stock repurchased during period	$ 38	$ 8
Amount available for further repurchases under stock repurchase program	$ 337
Time-Based Restricted Stock Units and Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	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	1 year
Vesting percentage	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%