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Earnings Per Share (Tables) | 12 Months Ended
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Dec. 31, 2016
Text Block [Abstract] |
Schedule Of Basic And Diluted Earnings Per Share |
|  |  | Years Ended December 31, |
$ in millions except share and per share amounts |  | 2016 |  | 2015 |  |  | 2014 |
Basic earnings per share: |  |  |  |  |  |  |  |  |  |
| Net income (loss) |  | $ | (338) |  | $ | 180 |  | $ | 569 |
| Less: undistributed earnings allocated to participating securities |  |  | - |  |  | 6 |  |  | 16 |
| Net income (loss) available to common shareholders |  |  | (338) |  |  | 174 |  |  | 553 |
| Basic weighted average shares (1) |  |  | 133,001,088 |  |  | 163,936,318 |  |  | 188,171,503 |
| Net income (loss) per basic common share |  | $ | (2.54) |  | $ | 1.06 |  | $ | 2.94 |
Diluted earnings per share: |  |  |  |  |  |  |  |  |  |
| Net income (loss) |  | $ | (338) |  | $ | 180 |  | $ | 569 |
| Less: undistributed earnings allocated to participating securities |  |  | - |  |  | 6 |  |  | 15 |
| Less: mark-to-market gain (loss) on warrants |  |  | - |  |  | - |  |  | 28 |
| Net income (loss) available to common shareholders |  |  | (338) |  |  | 174 |  |  | 526 |
| Basic weighted average shares (1) |  |  | 133,001,088 |  |  | 163,936,318 |  |  | 188,171,503 |
| Effect of common stock equivalents: |  |  |  |  |  |  |  |  |  |
| Stock options |  |  | - |  |  | 933,470 |  |  | 1,104,247 |
| Warrants |  |  | - |  |  | - |  |  | 1,622,877 |
| Diluted weighted average shares |  |  | 133,001,088 |  |  | 164,869,788 |  |  | 190,898,627 |
| Net income (loss) per diluted common share |  | $ | (2.54) |  | $ | 1.06 |  | $ | 2.76 |
| (1) Includes 930,406, 617,909 and 412,769 of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend |
| equivalents for the years ended December 31, 2016, 2015 and 2014, respectively. |

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