| **Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | 3 Months Ended | 6 Months Ended |
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| **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. |

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| - Definition
Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.
+ References
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| - Definition
Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.
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| - Definition
The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.
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| - Definition
The amount of net income (loss) derived from continuing operations during the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.
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| - Definition
Number of shares of stock issued during the period that is attributable to transactions involving issuance of stock not separately disclosed.
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| - Definition
The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.
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| - Definition
The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.
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| - Definition
Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.
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