Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net Income (Loss)	$ (109)		$ 192		$ (131)	$ 392
Weighted Average Number of Shares Outstanding, Basic (in shares)	387,000,000	[1]	361,000,000	[1]	378,000,000	361,000,000
Incremental Shares from Assumed Conversion of Dilutive Stock Options, Restricted Stock, and Shares of Common Stock in Rabbi Trust (in shares)	0	[2]	5,000,000	[2]	0	4,000,000
Weighted Average Number of Shares Outstanding, Diluted (in shares)	387,000,000		366,000,000		378,000,000	365,000,000
Earnings (Loss) from Continuing Operations Per Share, Basic (in dollars per share)	$ (0.28)		$ 0.53		$ (0.35)	$ 1.09
Earnings (Loss) from Continuing Operations Per Share, Diluted (in dollars per share)	$ (0.28)		$ 0.52		$ (0.35)	$ 1.07
Number of antidilutive stock options, shares of restricted stock and shares of common stock in rabbi trust excluded from calculation above (in shares)	10,000,000		3,000,000		9,000,000	4,000,000
Underwritten public offering (in shares)					24,150,000

[1] The weighted average number of shares outstanding includes the weighted average shares of common stock issued in connection with the underwritten public offering of 24,150,000 shares of common stock of the Company in first quarter 2015.

[2] (2) For the three and six months ended June 30, 2015, all outstanding options and non-vested restricted shares have been excluded from the calculation of diluted EPS as the Company incurred losses. Therefore, inclusion of outstanding options and non-vested restricted shares in the calculation of diluted EPS would be anti-dilutive.