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	Common Stock Class B 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, 2018	$ 1,471					$ 1,037	$ 1,043		$ (62)	$ (547)
Beginning balance, shares at Dec. 31, 2018				137,158,010	12,799,999					(12,056,688)
Net income (loss)	60						60
Cumulative effect adjustment from adoption of new accounting guidance at Dec. 31, 2018		$ 3						$ 3
Other comprehensive income (loss)	(3)								(3)
Issuance of common stock related to exercises of options and vesting of RSUs	$ 1					1
Issuance of common stock related to exercises of options and vesting of RSUs, shares				1,367,148
Repurchase of common stock, shares	0
Withholding taxes on net share settlements of equity awards	$ (26)					(26)
Stock-based compensation	69					69
Ending balance at Jun. 30, 2019	1,575					1,081	1,106		(65)	$ (547)
Ending balance, shares at Jun. 30, 2019				138,525,158	12,799,999					(12,056,688)
Beginning balance at Mar. 31, 2019	1,507					1,046	1,072		(64)	$ (547)
Beginning balance, shares at Mar. 31, 2019				138,256,630	12,799,999					(12,056,688)
Net income (loss)	34						34
Other comprehensive income (loss)	(1)								(1)
Issuance of common stock related to exercises of options and vesting of RSUs	$ 1					1
Issuance of common stock related to exercises of options and vesting of RSUs, shares				268,528
Repurchase of common stock, shares	0
Withholding taxes on net share settlements of equity awards	$ (4)					(4)
Stock-based compensation	38					38
Ending balance at Jun. 30, 2019	1,575					1,081	1,106		(65)	$ (547)
Ending balance, shares at Jun. 30, 2019				138,525,158	12,799,999					(12,056,688)
Beginning balance at Dec. 31, 2019	$ 1,161					1,150	681		(63)	$ (607)
Beginning balance, shares at Dec. 31, 2019	124,581,773		12,799,999	138,698,307	12,799,999					(14,116,534)
Net income (loss)	$ (169)						(169)
Cumulative effect adjustment from adoption of new accounting guidance at Dec. 31, 2019	681	$ (3)						$ (3)
Other comprehensive income (loss)	(5)								(5)
Issuance of common stock related to exercises of options and vesting of RSUs, shares				1,713,944
Repurchase of common stock	$ (115)									$ (115)
Repurchase of common stock, shares	(4,707,450)									(4,707,450)
Withholding taxes on net share settlements of equity awards	$ (17)					(17)
Stock-based compensation	60					60
Other, shares										(20,630)
Ending balance at Jun. 30, 2020	$ 912					1,193	509		(68)	$ (722)
Ending balance, shares at Jun. 30, 2020	121,567,637		12,799,999	140,412,251	12,799,999					(18,844,614)
Beginning balance at Mar. 31, 2020	$ 1,027					1,167	662		(80)	$ (722)
Beginning balance, shares at Mar. 31, 2020			12,799,999	140,109,681						(18,823,984)
Net income (loss)	(153)						(153)
Other comprehensive income (loss)	$ 12								12
Issuance of common stock related to exercises of options and vesting of RSUs, shares				302,570
Repurchase of common stock, shares	0
Withholding taxes on net share settlements of equity awards	$ (3)					(3)
Stock-based compensation	29					29
Other, shares										(20,630)
Ending balance at Jun. 30, 2020	$ 912					$ 1,193	$ 509		$ (68)	$ (722)
Ending balance, shares at Jun. 30, 2020	121,567,637		12,799,999	140,412,251	12,799,999					(18,844,614)