Condensed Consolidated Statement of Changes in Stockholders' Equity - 3 months ended Mar. 31, 2018 - USD ($) $ in Millions	Total	Class B Common Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2017	$ 1,363			$ 926	$ 926	$ (42)	$ (447)
Beginning balance, shares at Dec. 31, 2017	126,142,773	12,799,999	135,617,263				(9,474,490)
Net income	$ 5				5
Cumulative effect adjustment from adoption of new accounting guidance (Note 2)	4				4
Other comprehensive income	8					8
Issuance of common stock related to exercises of options and vesting of RSUs, shares			779,609
Repurchase of common stock	$ (10)						$ (10)
Repurchase of common stock, shares	(252,650)						(252,650)
Withholding taxes on net share settlements of equity awards	$ (12)			(12)
Stock-based compensation	32			32
Ending balance at Mar. 31, 2018	$ 1,390			$ 946	$ 935	$ (34)	$ (457)
Ending balance, shares at Mar. 31, 2018	126,669,732	12,799,999	136,396,872				(9,727,140)