Condensed Consolidated Statement of Changes in Stockholders' Equity - 9 months ended Sep. 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	$ 119				119
Cumulative effect adjustment from adoption of ASU 2016-09 (Note 2)	(1)				(1)
Other comprehensive income	4					4
Issuance of common stock related to exercises of options and vesting of RSUs	6			6
Issuance of common stock related to exercises of options and vesting of RSUs, shares			729,472
Repurchase of common stock	$ (21)						$ (21)
Repurchase of common stock, shares	(350,399)						(350,399)
Withholding taxes on net share settlements of equity awards	$ (13)			(13)
Stock-based compensation	74			74
Ending balance at Sep. 30, 2016	$ 1,580			$ 808	$ 944	$ (59)	$ (113)
Ending balance, shares at Sep. 30, 2016	132,822,184	12,799,999	134,565,714				(1,743,530)