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Regulatory Matters (Schedule of GCR Reconciliation Filing Pending with the MPSC) (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2013 Consumers Energy Company [Member] | Dec. 31, 2012 Consumers Energy Company [Member] | Dec. 31, 2011 Consumers Energy Company [Member] | Mar. 31, 2013 Gas Cost Recover (GCR) [Member] Consumers Energy Company [Member] | Mar. 31, 2012 Gas Cost Recover (GCR) [Member] Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items] |  |  |  |  |  |  |  |
Date Of Filing |  |  |  |  |  |  | June 2013 |
Net Over/(Under) Recovery, Including Interest, Requested by Consumers |  |  |  |  |  |  | $ (22) |
Cost of gas sold | $ 1,228 | $ 1,150 | $ 1,512 | $ 1,187 | $ 1,110 | $ 1,438 | $ 900 | $ 900

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- Definition Date of Filing + References No definition available. + Details
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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 Cost of natural gas purchased and associated transportation and storage costs during the period. + References No definition available. + Details
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- Details
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