| 11. | Asset Retirement Obligations |
The following table describes changes to the Corporation’s asset retirement obligations:
| 2013 | 2012 | |||||||
| (In millions) | ||||||||
|
Asset retirement obligations at January 1 |
$ | 2,661 | $ | 2,071 | ||||
|
Liabilities incurred |
42 | 186 | ||||||
|
Liabilities settled or disposed of |
(576 | ) | (324 | ) | ||||
|
Accretion expense |
129 | 135 | ||||||
|
Revisions of estimated liabilities |
573 | 529 | ||||||
|
Foreign currency translation |
(57 | ) | 64 | |||||
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Asset retirement obligations at December 31 |
2,772 | 2,661 | ||||||
|
Less: Current obligations |
523 | 449 | ||||||
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Long-term obligations at December 31 |
$ | 2,249 | $ | 2,212 | ||||
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The revisions in 2013 and 2012 reflect overall increases in estimated abandonment obligations resulting from changes in the expected scope of operations, increases in the time expected to complete dismantlement activities and updates to service rates.