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           ASSET RETIREMENT OBLIGATIONS (Tables) 
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           Dec. 31, 2012 
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| ASSET RETIREMENT OBLIGATIONS | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of changes to asset retirement obligation liabilities | 
 The following table describes changes to our asset retirement obligation liabilities, all of which were recorded in other noncurrent liabilities on the accompanying balance sheets (dollars in millions): 
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- Definition 
          Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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