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Regulatory Matters (Schedule of PSCR Reconciliation Filings Pending with the MPSC) (Details) (Power Supply Cost Recover (PSCR) [Member], Consumers Energy Company [Member], USD $) | 12 Months Ended
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Dec. 31, 2011 | Dec. 31, 2010
Power Supply Cost Recover (PSCR) [Member] | Consumers Energy Company [Member] |  |
Date of Filing | March 2012 |
Net Over/(Under) Recovery, Including Interest, Requested by Consumers | $ 8,000,000 |
PSCR Cost of Power Sold | $ 1,800,000,000 | $ 1,700,000,000

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- Definition Net over-/(under-) recovery of expense, including interest, requested by Consumers. + References No definition available. + Details
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- Definition Total costs related to electricity produced and sold during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 2 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688 + Details
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