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Commitments, Guarantees and Contingencies - Environmental Matters (Details) (USD $) In Millions, unless otherwise specified | Dec. 31, 2011
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Boswell Unit 4 [Member] |
Environmental Matters [Line Items] |
minimum amount expected to be invested for compliance costs | $ 300
maximum amount expected to be invested for compliance costs | 400
Manufactured Gas Plant Site [Member] |
Environmental Matters [Line Items] |
Liability for Remediation of Manufactured Gas Plant Site | $ 0.5

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- Definition The maximum amount expected to be invested for compliance costs for the MATS Rule. + References No definition available. + Details
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- Definition The minimum amount expected to be invested for compliance costs of the MATS Rule. + References No definition available. + Details
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- Details
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- Definition Carrying amount of the liability for remediation of environmental damage pertaining to assets or businesses previously disposed. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 5 -Section Y -Paragraph Question 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 5.Y.Q4) -URI http://asc.fasb.org/extlink&oid=6572457&loc=d3e149879-122751 + Details
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