| **Net Income Per Common Share (Tables)**              | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
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| **Earnings Per Share [Abstract]**                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| Calculations For Basic And Diluted Earnings Per Share | The table shows calculations for basic and diluted earnings per share:(Dollars in millions except share data in thousands) Three months ended March 31, 2013 2012Numerator:    Net income—basic and diluted $154 $86Denominator:    Weighted-average common shares outstanding 163,133 162,277Effect of stock-based awards:    Nonvested shares 783 541Stock options 1,008 327Adjusted weighted-average shares 164,924 163,145Earnings per share:    Basic $0.95 $0.53Diluted 0.94 0.53Number of anti-dilutive stock-based awards 2,056 6,215 |

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| - Definition
Tabular disclosure of an entity's basic and diluted earnings per share calculations.
+ References
No definition available.
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