|**Net Income Per Common Share (Tables)**              | 9 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 September 30,Nine months ended September 30,2013201220132012Numerator:Net income—basic and diluted$131$111$395$229Denominator:Weighted-average common shares outstanding163,710162,555163,454162,419Effect of stock-based awards:Stock options1,1845631,131441Nonvested shares707739719647Adjusted weighted-average shares165,601163,857165,304163,507Earnings per share:Basic$0.80$0.69$2.42$1.41Diluted0.790.682.391.40Number of anti-dilutive stock-based awards3355,0453906,000
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|(Dollars in millions except share data in thousands)  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|                                                      | 2013                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Numerator:                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Net income—basic and diluted                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Denominator:                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Weighted-average common shares outstanding            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Effect of stock-based awards:                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Stock options                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Nonvested shares                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Adjusted weighted-average shares                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Earnings per share:                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Basic                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Diluted                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Number of anti-dilutive stock-based awards            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

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                    duration X- DefinitionTabular disclosure of an entity's basic and diluted earnings per share calculations, including a reconciliation of numerators and denominators of the basic and diluted per-share computations for income from continuing operations.+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257+ Details**Name:**
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