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Asset Retirement Obligations and Accrued Environmental Costs (Tables) | 12 Months Ended
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Dec. 31, 2011
Asset Retirement Obligations and Accrued Environmental Costs | Asset retirement obligations and accrued environmental costs at December 31 were:
|  | Millions of Dollars |
|  | 2011 |  |  | 2010 |
Asset retirement obligations |  | $ | 8,920 |  |  |  | 8,776 |
Accrued environmental costs |  |  | 922 |  |  |  | 994 |
Total asset retirement obligations and accrued environmental costs |  |  | 9,842 |  |  |  | 9,770 |
Asset retirement obligations and accrued environmental costs due within one year* |  |  | (513 | ) |  |  | (571 | )
Long-term asset retirement obligations and accrued environmental costs |  | $ | 9,329 |  |  |  | 9,199 |
* | Classified as a current liability on the balance sheet, under the caption “Other accruals.”
Changes in Overall Asset Retirement Obligation Changed | During 2011 and 2010, our overall asset retirement obligation changed as follows:
|  | Millions of Dollars |
|  | 2011 |  |  | 2010 |
Balance at January 1 |  | $ | 8,776 |  |  |  | 8,295 |
Accretion of discount |  |  | 435 |  |  |  | 422 |
New obligations |  |  | 153 |  |  |  | 64 |
Changes in estimates of existing obligations |  |  | 29 |  |  |  | 744 |
Spending on existing obligations |  |  | (327 | ) |  |  | (314 | )
Property dispositions |  |  | (60 | ) |  |  | (394 | )
Foreign currency translation |  |  | (86 | ) |  |  | (41 | )
Balance at December 31 |  | $ | 8,920 |  |  |  | 8,776 |

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- Definition Disclosures of asset retirement obligations and environmental loss contingencies. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Examples of environmental loss contingencies are presence of hazardous waste, relevant information from reports issued by regulators, and estimated costs to achieve compliance with regulatory requirements. + References No definition available. + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859 + Details
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