XML 42 R55.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Regulatory Matters (Narrative) (Details) (USD $) | 12 Months Ended | 1 Months Ended | 12 Months Ended |  | 1 Months Ended | 12 Months Ended |  | 12 Months Ended |  | 1 Months Ended | 12 Months Ended |  | 1 Months Ended | 12 Months Ended | 1 Months Ended | 12 Months Ended | 1 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2013 Consumers Energy Company [Member] site | Dec. 31, 2013 Consumers Energy Company [Member] site | Dec. 31, 2012 Consumers Energy Company [Member] | Dec. 31, 2011 Consumers Energy Company [Member] | Nov. 30, 2013 Consumers Energy Company [Member] | May 31, 2013 Electric Rate Case [Member] Consumers Energy Company [Member] | Mar. 31, 2013 Electric Rate Case [Member] Consumers Energy Company [Member] | Jan. 31, 2013 Electric Rate Case [Member] Consumers Energy Company [Member] | Sep. 30, 2012 Electric Rate Case [Member] Consumers Energy Company [Member] | Dec. 31, 2012 Power Supply Cost Recover (PSCR) [Member] Consumers Energy Company [Member] | Dec. 31, 2011 Power Supply Cost Recover (PSCR) [Member] Consumers Energy Company [Member] | May 31, 2013 Power Supply Cost Recover (PSCR) [Member] 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] | May 31, 2013 Gas Cost Recover (GCR) [Member] Consumers Energy Company [Member] | Aug. 31, 2012 2011-2012 Gas Revenue Decoupling Mechanism [Member] Consumers Energy Company [Member] | Dec. 31, 2013 Electric Energy Optimization Plan [Member] Consumers Energy Company [Member] | Dec. 31, 2013 Gas Energy Optimization Plan [Member] Consumers Energy Company [Member] | Jun. 30, 2012 Cancelled Coal-Fueled Plant Costs [Member] Consumers Energy Company [Member] | Dec. 31, 2013 Coal Fueled Electric Generating Units [Member] Consumers Energy Company [Member] site | Dec. 31, 2013 Coal Fueled Electric Generating Units [Member] Consumers Energy Company [Member] site MW | Dec. 31, 2013 Gas Fueled Electric Generating Units [Member] Consumers Energy Company [Member] site | Dec. 31, 2013 Gas Fueled Electric Generating Units [Member] Consumers Energy Company [Member] site | Dec. 31, 2013 Manufactured Gas Plant [Member] Consumers Energy Company [Member] site | Dec. 31, 2013 Gas Storage Inventory Adjustments [Member] Consumers Energy Company [Member] | Dec. 31, 2012 DOE Settlement [Member] Consumers Energy Company [Member] | Dec. 31, 2011 DOE Settlement [Member] Consumers Energy Company [Member] | Jan. 31, 2013 Renewable Energy Grant [Member] Consumers Energy Company [Member]
Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Energy optimization incentive authorized for exceeding 2012 savings targets |  |  |  |  |  |  |  | $ 17,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percent of savings target achieved |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 140.00% | 122.00% |  |  |  |  |  |  |  |  |  |
Energy optimization incentive requested for exceeding savings targets |  |  |  | 18,000,000 | 18,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 17,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Authorized recovery, collection period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4 months |  |  |  |  |  |  |  | 10 years | 5 years |  |  |
Authorized Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 14,000,000 |  |  |  |  |  |  |  |  |
Authorized sale of securitized bonds |  |  |  | 389,000,000 | 389,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of units planned to be retired |  |  |  | 10 | 10 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 | 7 | 3 | 3 |  |  |  |  |
Number of former MGPs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 23 |  |  |  |
Power generation of cancelled plant |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 830 |  |  |  |  |  |  |
Proceeds from government grant | 69,000,000 |  |  |  | 69,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 69,000,000
Litigation settlement, gross |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 120,000,000 |
Approved refund of spent nuclear fuel costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 23,000,000 |  |
Annual rate increase requested |  |  |  |  |  |  |  |  |  |  | 145,000,000 | 148,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rate of return on equity requested |  |  |  |  |  |  |  |  |  |  |  | 10.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual rate increase authorized |  |  |  |  |  |  |  |  | 89,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rate of return on equity authorized |  |  |  |  |  |  |  |  | 10.30% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual rate increase self-implemented |  |  |  |  |  |  |  |  |  | 110,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
PSCR Cost of Power Sold |  |  |  |  |  |  |  |  |  |  |  |  | 1,900,000,000 | 1,800,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Over recovery authorized by the MPSC |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 8,000,000 |  |  | 2,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Cost of gas sold | $ 1,228,000,000 | $ 1,150,000,000 | $ 1,512,000,000 |  | $ 1,187,000,000 | $ 1,110,000,000 | $ 1,438,000,000 |  |  |  |  |  |  |  |  | $ 900,000,000 | $ 900,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition The amount the MPSC authorized collection from customers. + References No definition available. + Details
Name: | cms_AuthorizedRecovery
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Authorized recovery, collection period + References No definition available. + Details
Name: | cms_AuthorizedRecoveryCollectionPeriod
Namespace Prefix: | cms_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of spent nuclear fuel disposal costs incurred and collected from customers through rates that the MPSC has authorized for refund + References No definition available. + Details
Name: | cms_AuthorizedRefundOfSpentNuclearFuelDisposalCostsCollected
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of securitization bonds authorized. + References No definition available. + Details
Name: | cms_AuthorizedSaleOfSecuritizedBonds
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Energy optimization incentive authorized by the MPSC for achieving electric and gas savings targets. + References No definition available. + Details
Name: | cms_EnergyOptimizationIncentiveAuthorized
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Net over-/(under-) recovery of expense, including interest, authorized by the MPSC. + References No definition available. + Details
Name: | cms_NetOverUnderRecoveryOfExpenseIncludingInterestAuthorized
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of Former Manufactured Gas Plants + References No definition available. + Details
Name: | cms_NumberOfFormerManufacturedGasPlants
Namespace Prefix: | cms_
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of units planned to be retired. + References No definition available. + Details
Name: | cms_NumberOfUnitsPlannedToBeRetired
Namespace Prefix: | cms_
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percent of energy optimization savings targets achieved during the year. + References No definition available. + Details
Name: | cms_PercentOfSavingsTargetAchieved
Namespace Prefix: | cms_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Power generation of cancelled plant + References No definition available. + Details
Name: | cms_PowerGenerationOfCancelledPlant
Namespace Prefix: | cms_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Cash grant received from government during the current period. + References No definition available. + Details
Name: | cms_ProceedsFromGovernmentGrant
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | cms_RegulatoryMattersLineItems
Namespace Prefix: | cms_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Energy optimization incentive requested for achieving electric and gas savings targets. + References No definition available. + Details
Name: | cms_RequestedEnergyOptimizationIncentive
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of requested recovery. + References No definition available. + Details
Name: | cms_RequestedRecovery
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_CostOfGoodsSoldElectric
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cost of natural gas purchased and associated transportation and storage costs during the period. + References No definition available. + Details
Name: | us-gaap_CostOfNaturalGasPurchases
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of judgment or settlement awarded to (against) the entity in respect of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of public utility's approved rate increase (decrease) by regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's approved return on equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesInterimRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's requested return on equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedReturnOnEquityPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration