Condensed Consolidated Statement of Changes in Stockholders' Equity - 6 months ended Jun. 30, 2016 - 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, 2015	$ 1,412			$ 741	$ 826	$ (63)	$ (92)
Beginning balance, shares at Dec. 31, 2015	132,443,111	12,799,999	133,836,242				(1,393,131)
Net income	$ 62				62
Other comprehensive income	1					1
Issuance of common stock related to exercises of options and vesting of RSUs	3			3
Issuance of common stock related to exercises of options and vesting of RSUs, shares			594,026
Repurchase of common stock	$ (12)						$ (12)
Repurchase of common stock, shares	(208,137)						(208,137)
Tax benefits on equity awards, net	$ 3			3
Minimum withholding taxes on net share settlements of equity awards	(11)			(11)
Stock-based compensation	47			47
Ending balance at Jun. 30, 2016	$ 1,505			$ 783	$ 888	$ (62)	$ (104)
Ending balance, shares at Jun. 30, 2016	132,829,000	12,799,999	134,430,268				(1,601,268)