Consolidated Statements of Shareholders' Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock	Additional Paid in Capital	Accumulated Other Comprehensive Loss	Treasury Stock at Cost	Retained Earnings
Balance at Beginning of Period at Dec. 31, 2013	$ 9,184	$ 4	$ 3,463	$ (117)	$ (659)	$ 6,493
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	392	0	0	0	0	392
Stock-based Compensation	45	0	45	0	0	0
Exercise of Stock Options	41	0	41	0	0	0
Dividends	(116)	0	0	0	0	(116)
Changes in Treasury Stock, Net	(15)	0	0	0	(15)	0
Tax Benefits Related to Exercise of Stock Options	17	0	17	0	0	0
Net Change in Pension and Other	6	0	0	6	0	0
Balance at End of Period at Jun. 30, 2014	9,554	4	3,566	(111)	(674)	6,769
Balance at Beginning of Period at Dec. 31, 2014	10,325	4	3,624	(90)	(671)	7,458
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(131)	0	0	0	0	(131)
Stock-based Compensation	38	0	38	0	0	0
Exercise of Stock Options	4	0	4	0	0	0
Dividends	(134)	0	0	0	0	(134)
Changes in Treasury Stock, Net	(12)	0	0	0	(12)	0
Issuance of Shares of Common Stock to Public, Net of Offering Costs	1,112	0	1,112	0	0	0
Net Change in Pension and Other	7	0	0	7	0	0
Balance at End of Period at Jun. 30, 2015	$ 11,209	$ 4	$ 4,778	$ (83)	$ (683)	$ 7,193