CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	New Accounting Pronouncement, Early Adoption, Effect	Class A Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Retained Earnings New Accounting Pronouncement, Early Adoption, Effect	Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, Shares			52,161,851
Beginning Balance at Dec. 31, 2015	$ 893		$ 1	$ 194	$ (631)	$ 1,377		$ (48)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, Shares			52,884,588
Issuance of treasury shares upon exercise of stock options, purchases under stock purchase plan and grants of restricted stock awards, shares			817,943
Issuance of treasury shares upon exercise of stock options, purchases under stock purchase plan and grants of restricted stock awards net of cancellations	11			(14)	25
Shares withheld related to net share settlement (in shares)			(95,206)
Shares withheld related to net share settlement	(8)				(8)
Additional tax benefit resulting from exercise of options	3			3
Share-based compensation	27			27
Net income (loss)	(137)					(137)
Unrealized loss on anticipated sales hedging transactions (net of income taxes)	7							7
Unrealized gain on forward interest rate swaps hedging transactions (net of income taxes)	0
Foreign currency translation adjustment	(4)							(4)
Ending Balance at Dec. 31, 2016	792		$ 1	210	(614)	1,240		(45)
Ending Balance, Shares at Dec. 31, 2016			52,884,588
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, Shares			52,884,588
Beginning Balance, Shares			53,236,095
Issuance of treasury shares upon exercise of stock options, purchases under stock purchase plan and grants of restricted stock awards, shares			410,239
Issuance of treasury shares upon exercise of stock options, purchases under stock purchase plan and grants of restricted stock awards net of cancellations	12			12	0
Shares withheld related to net share settlement (in shares)			(58,732)
Shares withheld related to net share settlement	(6)				(6)
Share-based compensation	35			35
Net income (loss)	17					17
Unrealized loss on anticipated sales hedging transactions (net of income taxes)	(15)							(15)
Unrealized gain on forward interest rate swaps hedging transactions (net of income taxes)	6							6
Foreign currency translation adjustment	2							2
Ending Balance at Dec. 31, 2017	834		$ 1	257	(620)	1,248		(52)
Ending Balance, Shares at Dec. 31, 2017			53,236,095
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, Shares			53,236,095
Cumulative effect of change in accounting principle	9					(9)
Beginning Balance, Shares			53,871,184
Issuance of treasury shares upon exercise of stock options, purchases under stock purchase plan and grants of restricted stock awards, shares			704,137
Issuance of treasury shares upon exercise of stock options, purchases under stock purchase plan and grants of restricted stock awards net of cancellations	10			(8)	18
Shares withheld related to net share settlement (in shares)			(69,048)
Shares withheld related to net share settlement	(11)				(11)
Share-based compensation	45			45
Net income (loss)	421					421
Unrealized loss on anticipated sales hedging transactions (net of income taxes)	21							21
Unrealized gain on forward interest rate swaps hedging transactions (net of income taxes)	9							9
Foreign currency translation adjustment	(13)							(13)
Ending Balance at Dec. 31, 2018	$ 1,335		$ 1	$ 294	$ (613)	$ 1,688		$ (35)
Ending Balance, Shares at Dec. 31, 2018			53,871,184
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, Shares			53,871,184
Cumulative effect of change in accounting principle | ASU 2016-16		$ 19					$ 19