Condensed Consolidated Statement of Shareholders' Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Deferred Equity Compensation [Member]
Beginning balance at Dec. 31, 2016					$ 149
Increase (Decrease) in Shareholders' Equity
Net Income	$ 317
Other comprehensive loss	57
Less: reclassification adjustment for gains (losses) included in net income (loss), net of tax provision (benefit) of $(1)	0
Ending balance at Mar. 31, 2017					206
Beginning balance (in shares) at Dec. 31, 2017		116,020,852
Beginning balance at Dec. 31, 2017	6,839	$ 1	$ 573	$ 5,892	372	$ 1
Increase (Decrease) in Shareholders' Equity
Net Income	197			197
Dividends ($0.16 per share)	(19)			(19)
Common stock repurchases (in shares)		(2,787,936)
Common stock repurchases	(98)	$ 0	(98)
Share-based compensation and other (in shares)		476,406
Share-based compensation and other	(9)	$ 0	(9)			0
Other comprehensive loss	(126)				(126)
Less: reclassification adjustment for gains (losses) included in net income (loss), net of tax provision (benefit) of $(1)	(2)
Less: reclassification adjustment for gains (losses) included in net income (loss), net of tax provision (benefit) of $(1) | Accounting Standards Update 2016-01 [Member]	33
Effect of adoption of ASU 2016-01 (see Note 1)					32
Effect of adoption of ASU 2016-01 (see Note 1) | Accounting Standards Update 2016-01 [Member]				(32)	32
Ending balance (in shares) at Mar. 31, 2018		113,709,322
Ending balance at Mar. 31, 2018	$ 6,784	$ 1	$ 466	$ 6,102	$ 214	$ 1