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]
Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding			163.0
Balance at beginning of period at Dec. 31, 2012		$ 1,282	$ 2	$ 358	$ 929	$ (37)	$ 30
Comprehensive income (loss):
Net income (loss)		446			443		3
Other comprehensive (loss) income	$ (8)	(6)				(1)	(5)
Total comprehensive income (loss)		440			443	(1)	(2)
Employee stock purchase and stock compensation plans		83		83
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests		(28)		(8)			(20)
Acquisition of noncontrolling interest		9					9
Dividend distribution		(3)					(3)
Employee stock purchase and stock compensation plans (in shares)			4.0
Balance at end of period at Dec. 31, 2013		1,783	$ 2	433	1,372	(38)	14
Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding			167.0
Comprehensive income (loss):
Net income (loss)		192			191		1
Other comprehensive (loss) income	(101)	(99)				(98)	(1)
Total comprehensive income (loss)		93			191	(98)	0
Employee stock purchase and stock compensation plans		9		9
Dividend distribution		(2)		0			(2)
Employee stock purchase and stock compensation plans (in shares)			2.0
Balance at end of period at Dec. 31, 2014	$ 1,883	1,883	$ 2	442	1,563	(136)	12
Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding	168.6		169.0
Comprehensive income (loss):
Net income (loss)		(176)			(178)		2
Other comprehensive (loss) income	$ (17)	(16)				(14)	(2)
Total comprehensive income (loss)		(192)			(178)	(14)	0
Employee stock purchase and stock compensation plans		50		50
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests		(6)					(6)
Dividend distribution		(4)			(4)
Employee stock purchase and stock compensation plans (in shares)			1.0
Stock Repurchased During Period, Shares			(37.0)
Stock Repurchased During Period, Value		(1,005)	$ (1)	(492)	(512)
Balance at end of period at Dec. 31, 2015	$ 726	$ 726	$ 1	$ 0	$ 869	$ (150)	$ 6
Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding	133.0		133.0