Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid in Capital	Accumulated Other Comprehensive Loss	Treasury Stock at Cost	Retained Earnings	Noncontrolling Interest [Member]
Balance at Beginning of Period at Dec. 31, 2015	$ 10,370	$ 5	$ 6,360	$ (33)	$ (688)	$ 4,726	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(287)	0	0	0	0	(287)	0
Stock-based Compensation	19	0	19	0	0	0	0
Dividends	(41)	0	0	0	0	(41)	0
Other	(9)	0	(1)	0	(8)	0	0
Balance at End of Period at Mar. 31, 2016	10,052	5	6,378	(33)	(696)	4,398	0
Balance at Beginning of Period at Dec. 31, 2016	9,600	5	6,450	(31)	(692)	3,556	312
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	47	0	0	0	0	36	11
Stock-based Compensation	13	0		0	0	0	0
Dividends	(44)	0	0	0	0	(44)	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(6)	0	0	0	0	0	(6)
Other	(1)	0	9	0	(11)	1	0
Balance at End of Period at Mar. 31, 2017	$ 9,609	$ 5	$ 6,472	$ (31)	$ (703)	$ 3,549	$ 317