Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Class B Common Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Treasury Stock
Beginning balance at Dec. 31, 2015	$ 1,412			$ 741	$ 826	$ (63)	$ (92)
Beginning balance, shares at Dec. 31, 2015		12,799,999	133,836,242				(1,393,131)
Net income (loss)	120				120
Cumulative effect adjustment from adoption of new accounting guidance related to stock-based compensation	(1)				(1)
Other comprehensive (loss) income	(14)					(14)
Issuance of common stock related to exercise of options and vesting of RSUs	7			7
Issuance of common stock related to exercise of options and vesting of RSUs, shares			870,225
Repurchase of common stock (Note 16)	$ (105)						$ (105)
Repurchase of common stock, shares	(2,002,356)						(2,002,356)
Withholding taxes on net share settlements of equity awards	$ (15)			(15)
Stock-based compensation (Note 6)	98			98
Ending balance at Dec. 31, 2016	1,502			831	945	(77)	$ (197)
Ending balance, shares at Dec. 31, 2016		12,799,999	134,706,467				(3,395,487)
Net income (loss)	(19)				(19)
Other comprehensive (loss) income	35					35
Issuance of common stock related to exercise of options and vesting of RSUs	3			3
Issuance of common stock related to exercise of options and vesting of RSUs, shares			910,796
Repurchase of common stock (Note 16)	$ (250)						$ (250)
Repurchase of common stock, shares	(6,079,003)						(6,079,003)
Withholding taxes on net share settlements of equity awards	$ (17)			(17)
Stock-based compensation (Note 6)	109			109
Ending balance at Dec. 31, 2017	$ 1,363			926	926	(42)	$ (447)
Ending balance, shares at Dec. 31, 2017	126,142,773	12,799,999	135,617,263				(9,474,490)
Net income (loss)	$ 113				113
Cumulative effect adjustment from adoption of new accounting guidance related to stock-based compensation	4				4
Other comprehensive (loss) income	(20)					(20)
Issuance of common stock related to exercise of options and vesting of RSUs	6			6
Issuance of common stock related to exercise of options and vesting of RSUs, shares			1,540,747
Repurchase of common stock (Note 16)	$ (100)						$ (100)
Repurchase of common stock, shares	(2,582,198)						(2,582,198)
Withholding taxes on net share settlements of equity awards	$ (26)			(26)
Stock-based compensation (Note 6)	131			131
Ending balance at Dec. 31, 2018	$ 1,471			$ 1,037	$ 1,043	$ (62)	$ (547)
Ending balance, shares at Dec. 31, 2018	125,101,322	12,799,999	137,158,010				(12,056,688)