Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Total Stockholders Equity	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interest [Member]
Balance at beginning of period at Dec. 31, 2016		$ 699	$ 1	$ 32	$ 867	$ (205)	$ 4
Shares outstanding at beginning of period at Dec. 31, 2016			125.0
Comprehensive income (loss):
Net income (loss)		235			232		3
Other comprehensive (loss) income	$ 4	4				6	(2)
Total comprehensive income (loss)		239			232	6	1
Cumulative Effect on Retained Earnings, Net of Tax		39			39
Employee stock purchase and stock compensation plans		61		61
Employee stock purchase and stock compensation plans (in shares)			1.0
Stock Repurchased During Period, Shares			(7.0)
Stock Repurchased During Period, Value		(350)	$ 0	(178)	(172)
Dividends, Preferred Stock		(47)			(47)
Dividend distribution		(2)					(2)
Deemed dividend on modification of Series A convertible preferred stock	(4)	(4)			(4)
Deemed Dividend on Preferred Stock Redemption	(58)			58	(58)
Stock Redeemed or Called During Period, Shares			3.0
Stock Redeemed or Called During Period, Value		87		87
Balance at end of period at Dec. 31, 2017		722	$ 1	60	857	(199)	3
Shares outstanding at end of period at Dec. 31, 2017			122.0
Comprehensive income (loss):
Net income (loss)		(87)			(88)		1
Other comprehensive (loss) income	(50)	(48)				(48)
Total comprehensive income (loss)		(135)			(88)	(48)	1
Cumulative Effect on Retained Earnings, Tax		15			14	1
Employee stock purchase and stock compensation plans		56		56
Employee stock purchase and stock compensation plans (in shares)			2.0
Stock Repurchased During Period, Shares			(6.0)
Stock Repurchased During Period, Value		(210)	$ 0	(82)	(128)
Dividends, Preferred Stock		(49)			(49)
Balance at end of period at Dec. 31, 2018	$ 399	399	$ 1	34	606	(246)	4
Shares outstanding at end of period at Dec. 31, 2018	118.0		118.0
Comprehensive income (loss):
Net income (loss)		566			564		2
Other comprehensive (loss) income	$ (26)	(25)				(23)	(2)
Total comprehensive income (loss)		541			564	(23)	0
Employee stock purchase and stock compensation plans		94		94
Employee stock purchase and stock compensation plans (in shares)			3.0
Stock Repurchased During Period, Shares			(3.0)
Stock Repurchased During Period, Value		(96)		96
Dividends, Preferred Stock		(43)			(43)
Stock Issued During Period, Shares, Conversion of Convertible Securities			9.0
Redemption of Preferred Shares		(205)		(272)
Dividend distribution		(1)					1
Deemed Dividend on Preferred Stock Redemption	67				(67)
Repurchase of non-controlling interest		8		8
Balance at end of period at Dec. 31, 2019	$ 1,107	$ 1,107	$ 1	$ 312	$ 1,060	$ (269)	$ 3
Shares outstanding at end of period at Dec. 31, 2019	127.7		127.0