CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning Balance (in shares) at Dec. 31, 2018	62,100	62,000
Beginning Balance at Dec. 31, 2018	$ 1,647	$ 0	$ 643	$ (8)	$ 1,012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	198				198
Termination of warrants	(103)		(103)
Other comprehensive income (loss), net	5			5
Share-based compensation (in shares)		1,000
Share-based compensation	3		3
Ending Balance (in shares) at Mar. 31, 2019		63,000
Ending Balance at Mar. 31, 2019	$ 1,835	$ 0	543	(3)	1,295
Beginning Balance (in shares) at Dec. 31, 2019	61,900	62,000
Beginning Balance at Dec. 31, 2019	$ 1,960	$ 0	175	4	1,781
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	178				178
Common stock purchases (in shares)		(3,400)
Common stock purchases	(446)	$ (446)	(9)		(437)
Termination of warrants	(30)		(30)
Other comprehensive income (loss), net	(19)			(19)
Share-based compensation (in shares)		98
Share-based compensation	4		4
Ending Balance (in shares) at Mar. 31, 2020		59,000
Ending Balance at Mar. 31, 2020	$ 1,647	$ 0	$ 140	$ (15)	$ 1,522