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Asset Retirement Obligations (Tables) | 12 Months Ended
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Dec. 31, 2013
Asset Retirement Obligation Disclosure [Abstract] |
Change in Asset Retirement Obligations | The following table shows a rollforward of the AROs from January 1, 2012 to December 31, 2013. Amounts include conditional AROs.
| (In thousands) |  | 2013 |  | 2012 |
| Balance at January 1, | $ | 18,768 | $ | 19,173 |
| Liabilities incurred |  | 296 |  | 49 |
| Accretion expense |  | 1,015 |  | 1,021 |
| Liabilities settled |  | (744) |  | (221) |
| Revisions in estimated cash flows(a) |  | 24 |  | (1,254) |
| Balance at December 31, | $ | 19,359 | $ | 18,768 |
(a) In 2012, MGE re corded a decrease in revisions in estimated cash flows of $1.3 million based on revised asbestos abatement estimates.

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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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