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, 2014	$ 1,125			$ 673	$ 628	$ (31)	$ (145)
Beginning balance, shares at Dec. 31, 2014		12,799,999	132,315,465				(2,194,173)
Net income (loss)	198				198
Other comprehensive (loss) income	(32)					(32)
Issuance of common stock related to exercise of options and vesting of RSUs	$ 12			12
Issuance of common stock related to exercise of options and vesting of RSUs, shares			1,520,777
Repurchase of common stock, shares (Note 15)	0
Issuance of treasury stock as charitable contribution (Note 15)	$ 67			14			$ 53
Issuance of treasury stock as charitable contribution, Shares (Note 15)							801,042
Tax benefits on equity awards, net	35			35
Withholding taxes on net share settlements of equity awards	(73)			(73)
Stock-based compensation	80			80
Ending balance at Dec. 31, 2015	1,412			741	826	(63)	$ (92)
Ending 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 15)	$ (105)						$ (105)
Repurchase of common stock, shares (Note 15)	(2,002,356)						(2,002,356)
Withholding taxes on net share settlements of equity awards	$ (15)			(15)
Stock-based compensation	98			98
Ending balance at Dec. 31, 2016	$ 1,502			831	945	(77)	$ (197)
Ending balance, shares at Dec. 31, 2016	131,310,980	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 15)	$ (250)						$ (250)
Repurchase of common stock, shares (Note 15)	(6,079,003)						(6,079,003)
Withholding taxes on net share settlements of equity awards	$ (17)			(17)
Stock-based compensation	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)