Condensed Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment Revision of Prior Period, Adjustment	Class B Common Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment Revision of Prior Period, Adjustment	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2019	$ 1,161				$ 1,150	$ 681		$ (63)	$ (607)
Beginning balance, shares at Dec. 31, 2019			12,799,999	138,698,307					(14,116,534)
Net income (loss)	(16)					(16)
Cumulative effect adjustment from adoption of new accounting guidance at Dec. 31, 2019		$ (3)					$ (3)
Other comprehensive loss	(17)							(17)
Issuance of common stock related to exercises of options and vesting of RSUs, shares				1,411,374
Repurchase of common stock (Note 9)	$ (115)								$ (115)
Repurchase of common stock, shares	(4,707,450)								(4,707,450)
Withholding taxes on net share settlements of equity awards	$ (14)				(14)
Stock-based compensation	31				31
Ending balance at Mar. 31, 2020	1,027				1,167	662		(80)	$ (722)
Ending balance, shares at Mar. 31, 2020			12,799,999	140,109,681					(18,823,984)
Beginning balance at Dec. 31, 2020	$ 886				1,253	389		(34)	$ (722)
Beginning balance, shares at Dec. 31, 2020	121,930,607		12,799,999	140,775,221					(18,844,614)
Net income (loss)	$ (80)					(80)
Cumulative effect adjustment from adoption of new accounting guidance at Dec. 31, 2020	389
Other comprehensive loss	(12)							(12)
Issuance of common stock related to exercises of options and vesting of RSUs	$ 7				7
Issuance of common stock related to exercises of options and vesting of RSUs, shares				2,139,630
Repurchase of common stock, shares	0
Purchase of capped calls, net of tax of $9 million (Note 5)	$ (26)				(26)
Withholding taxes on net share settlements of equity awards	(23)				(23)
Stock-based compensation	33				33
Ending balance at Mar. 31, 2021	$ 785				$ 1,244	$ 309		$ (46)	$ (722)
Ending balance, shares at Mar. 31, 2021	124,070,237		12,799,999	142,914,851					(18,844,614)