EXHIBIT 12



COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES



The ratio of earnings to fixed charges is calculated using the Securities and Exchange Commission guidelines.



|                                                              |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|------------------------------------------------------------- |  | ----------------------- | --- | ---- | - | ---- |  | ---- | --- | ---- | - | --- |  | - | ---
|                                                              |  | Year Ended December 31,
|                                                              |  | 2007                    |     | 2006 |   | 2005 |  | 2004 |     | 2003
|                                                              |  | (dollars in millions)  
|Earnings as defined for fixed charges calculation             |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Add:                                                          |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Pretax income                                                 |  | $                       | 386 |      | $ | 200  |  | $    | 325 |      | $ | 277 |  | $ | 234
|Fixed charges                                                 |  |                         | 130 |      |   | 145  |  |      | 126 |      |   | 103 |  |   | 97 
|Deduct:                                                       |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Interest capitalized(a)                                       |  |                         | 11  |      |   | 16   |  |      | 8   |      |   | 2   |  |   | 5  
|                                                              |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Total earnings (as defined for the Fixed Charges calculation) |  | $                       | 505 |      | $ | 329  |  | $    | 443 |      | $ | 378 |  | $ | 326
|                                                              |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Fixed charges:                                                |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Interest on debt, including capitalized portions              |  | $                       | 120 |      | $ | 138  |  | $    | 118 |      | $ | 93  |  | $ | 88 
|Estimate of interest within rental expense                    |  |                         | 10  |      |   | 7    |  |      | 8   |      |   | 10  |  |   | 9  
|                                                              |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Total fixed charges                                           |  | $                       | 130 |      | $ | 145  |  | $    | 126 |      | $ | 103 |  | $ | 97 
|                                                              |  |                         |     |      |   |      |  |      |     |      |   |     |  |   |    
|Ratio of earnings to fixed charges                            |  |                         | 3.9 |      |   | 2.3  |  |      | 3.5 |      |   | 3.7 |  |   | 3.4



|(a) | Excludes equity costs related to AFUDC that are included in Other Income and Expenses in the Consolidated Statements of Operations.
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