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Earnings Per Share (Tables) | 12 Months Ended
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Dec. 31, 2015
Text Block [Abstract] |
Schedule Of Basic And Diluted Earnings Per Share |
|  |  | Years Ended December 31, |
$ in millions except share and per share amounts |  | 2015 |  | 2014 |  |  | 2013 |
Basic earnings per share: |  |  |  |  |  |  |  |  |  |
| Net income (loss) |  | $ | 180 |  | $ | 569 |  | $ | 250 |
| Less: undistributed earnings allocated to participating securities |  |  | 6 |  |  | 16 |  |  | 5 |
| Net income (loss) available to common shareholders |  |  | 174 |  |  | 553 |  |  | 245 |
| Basic weighted average shares (1) |  |  | 163,936,318 |  |  | 188,171,503 |  |  | 189,071,011 |
| Net income (loss) per basic common share |  | $ | 1.06 |  | $ | 2.94 |  | $ | 1.30 |
Diluted earnings per share: |  |  |  |  |  |  |  |  |  |
| Net income (loss) |  | $ | 180 |  | $ | 569 |  | $ | 250 |
| Less: undistributed earnings allocated to participating securities |  |  | 6 |  |  | 15 |  |  | 5 |
| Less: mark-to-market gain (loss) on warrants |  |  | - |  |  | 28 |  |  | - |
| Net income (loss) available to common shareholders |  |  | 174 |  |  | 526 |  |  | 245 |
| Basic weighted average shares (1) |  |  | 163,936,318 |  |  | 188,171,503 |  |  | 189,071,011 |
| Effect of common stock equivalents: |  |  |  |  |  |  |  |  |  |
| Stock options |  |  | 933,470 |  |  | 1,104,247 |  |  | 1,241,902 |
| Warrants |  |  | - |  |  | 1,622,877 |  |  | - |
| Diluted weighted average shares |  |  | 164,869,788 |  |  | 190,898,627 |  |  | 190,312,913 |
| Net income (loss) per diluted common share |  | $ | 1.06 |  | $ | 2.76 |  | $ | 1.29 |
| (1) Includes 617,909, 412,769 and 629,896 of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend |
| equivalents for the years ended December 31, 2015, 2014 and 2013, respectively. |

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- Definition Schedule of Basic and Diluted Earnings Per Share [Table Text Block] + References No definition available. + Details
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