Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Total Stockholders Equity	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Non-Redeemable Noncontrolling Interests in Subsidiaries
Balance at beginning of period (in shares) at Dec. 31, 2017			122.0
Balance at beginning of period at Dec. 31, 2017		$ 722	$ 1	$ 60	$ 857	$ (199)	$ 3
Comprehensive income:
Net income		20			20
Other comprehensive income		14				14
Total comprehensive income		34			20	14
Effects of adoption of new accounting standards		15			14	1
Employee stock purchase and stock compensation plans (in shares)			1.0
Employee stock purchase and stock compensation plans		8		8
Repurchase of Company common stock (in shares)			(5.0)
Repurchase of Company common stock		(165)		(68)	(97)
Series A convertible preferred stock dividends		(12)			(12)
Balance at end of period (in shares) at Mar. 31, 2018			118.0
Balance at end of period at Mar. 31, 2018		602	$ 1	0	782	(184)	3
Balance at beginning of period (in shares) at Dec. 31, 2018	118.7		119.0
Balance at beginning of period at Dec. 31, 2018	$ 399	399	$ 1	34	606	(246)	4
Comprehensive income:
Net income		38			37		1
Other comprehensive income		16				16
Total comprehensive income		54			37	16	1
Employee stock purchase and stock compensation plans (in shares)			1.0
Employee stock purchase and stock compensation plans		14		14
Series A convertible preferred stock dividends		(13)			(13)
Balance at end of period (in shares) at Mar. 31, 2019			120.0
Balance at end of period at Mar. 31, 2019		454	$ 1	48	630	(230)	5
Balance at beginning of period (in shares) at Dec. 31, 2018	118.7		119.0
Balance at beginning of period at Dec. 31, 2018	$ 399	399	$ 1	34	606	(246)	4
Comprehensive income:
Other comprehensive income	$ 5
Balance at end of period (in shares) at Jun. 30, 2019	119.8		120.0
Balance at end of period at Jun. 30, 2019	$ 547	547	$ 1	76	706	(241)	5
Balance at beginning of period (in shares) at Mar. 31, 2019			120.0
Balance at beginning of period at Mar. 31, 2019		454	$ 1	48	630	(230)	5
Comprehensive income:
Net income		88			88
Other comprehensive income	$ (11)	(11)				(11)
Total comprehensive income		77			88	(11)
Employee stock purchase and stock compensation plans		28		28
Series A convertible preferred stock dividends		(12)			(12)
Balance at end of period (in shares) at Jun. 30, 2019	119.8		120.0
Balance at end of period at Jun. 30, 2019	$ 547	$ 547	$ 1	$ 76	$ 706	$ (241)	$ 5