XML 132 R60.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Regulatory Matters (Narrative) (Details) (USD $) In Millions, unless otherwise specified |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 12 Months Ended |  |  |  | 1 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2011 Consumers Energy Company [Member] | Oct. 31, 2011 Consumers Energy Company [Member] | May 31, 2011 Consumers Energy Company [Member] | Dec. 31, 2010 Consumers Energy Company [Member] | Jun. 30, 2011 2010 Electric Rate Case [Member] Consumers Energy Company [Member] | Dec. 31, 2010 2010 Electric Rate Case [Member] Consumers Energy Company [Member] | Jun. 30, 2011 Power Supply Cost Recover (PSCR) [Member] Consumers Energy Company [Member] | Nov. 30, 2011 Gas Cost Recover (GCR) [Member] Consumers Energy Company [Member] | Mar. 31, 2011 Electric Revenue Decoupling Mechanism [Member] Consumers Energy Company [Member] | Nov. 30, 2011 Uncollectible Expense Tracking Mechanism [Member] Consumers Energy Company [Member] | Mar. 31, 2011 Uncollectible Expense Tracking Mechanism [Member] Consumers Energy Company [Member] | May 31, 2011 2010 Gas Rate Case [Member] Consumers Energy Company [Member] | Aug. 31, 2010 2010 Gas Rate Case [Member] Consumers Energy Company [Member] | Sep. 30, 2011 Gas Revenue Decoupling Mechanism [Member] Consumers Energy Company [Member] | Dec. 31, 2011 Big Rock Decommissioning And Related Costs [Member] Consumers Energy Company [Member] | Sep. 30, 2011 Big Rock Decommissioning And Related Costs [Member] Consumers Energy Company [Member] | Feb. 28, 2010 Big Rock Decommissioning And Related Costs [Member] Consumers Energy Company [Member] | Dec. 31, 2010 Refund Of Revenue In Excess Of Nuclear Decommissioning Costs [Member] Consumers Energy Company [Member] | Apr. 30, 2010 Refund Of Revenue In Excess Of Nuclear Decommissioning Costs [Member] Consumers Energy Company [Member] | Dec. 31, 2011 2011 Electric Energy Optimization Plan [Member] Consumers Energy Company [Member] | Dec. 31, 2011 2011 Gas Energy Optimization Plan [Member] Consumers Energy Company [Member] | Dec. 31, 2011 Big Rock Nuclear Decommissioning And Related Costs [Member] Consumers Energy Company [Member] | Sep. 30, 2011 Big Rock Nuclear Decommissioning And Related Costs [Member] Consumers Energy Company [Member] | Dec. 31, 2010 Big Rock Nuclear Decommissioning And Related Costs [Member] Consumers Energy Company [Member] | Jul. 31, 2011 DOE Settlement [Member] Consumers Energy Company [Member] | Dec. 31, 2011 DOE Settlement [Member] Consumers Energy Company [Member]
Annual Rate Increase Authorized by the MPSC |  |  |  |  |  |  |  | $ 146 |  |  |  |  |  | $ 31 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Annual Rate Increase Requested by Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 55 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Difference Between the Annual Rate Increase Authorized by MPSC and the Annual Rate Increase Self-implemented by Consumers |  |  |  |  |  |  |  | 4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of rates to be refunded to customers |  |  |  |  |  |  | 0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Requested Recovery |  |  |  |  |  |  |  |  |  |  | 27 |  | 3 |  |  | 16 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory assets | 2,466 | 2,093 | 2,466 |  |  | 2,093 |  |  |  |  |  |  |  |  |  |  | 85 |  |  |  |  |  |  | 85 | [1] |  | 85 | [1] |  |
Amount Paid to Transfer Ownership and Responsibility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 30 |  |  |  |  |  |  |  |  |  |  |  |  |
Regulatory liabilities | 125 | 22 | 125 |  |  | 22 |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 |  |  |  |  |  |  |  |  |  | 120
Amended Annual Renewable Energy Plan Surcharge Billed To Customers |  |  |  |  | 23 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed Amended Annual Renewable Energy Plan Surcharge Billed To Customers |  |  |  | 20 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Litigation Settlement, Gross |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 120 |
Proposed Recovery Of Regulatory Asset |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 85 |  |  |  |
Proposed Refund Of Spent Nuclear Fuel Disposal Costs Collected |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 23 |  |  |  |  |  |  |  |  |  |  |  |
Remaining Portion of Litigation Settlement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 12 |  |  |  |  |  |  |  |  |  |  |  |
Percentage of Difference Between Rate Base Expense and Actual Expense To Collect/Refund |  |  |  |  |  |  |  |  |  |  |  |  | 80.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Authorized Recovery |  |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Contributions to Fund Decommissioning Costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 44 |  |  |  |  |  |  |  |  |  |  |
Revenue Collected in Excess of the Costs Incurred to Decommission Big Rock, Plus Interest, and Ordered for Refund |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 85 |  |  |  |  |  |  |  |  |
Nuclear Fuel Storage Costs Incurred as a Result of the DOE's Failure to Accept Spent Nuclear Fuel |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 55 |  |  |  |  |  |  |  |  |  |  |  |  |
Annual Amount Of Reduction Of Renewable Energy Plan Surcharge Billed To Customers |  |  |  |  | 54 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proposed Annual Amount Of Reduction Of Renewable Energy Plan Surcharge Billed To Customers |  |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Authorized Energy Optimization Incentive for Exceeding Savings Targets |  |  | 8 |  | 6 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percent of Savings Target Achieved |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 138.00% | 129.00% |  |  |  |  |  |  |
Energy Optimization Incentive to be Requested for Exceeding 2011 Savings Targets |  |  | 15 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rate of Return on Equity Requested by Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 11.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rate of Return On Equity Authorized by the MPSC |  |  |  |  |  |  |  |  |  |  |  |  |  | 10.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Over/(Under) Recovery, Including Interest, Authorized by the MPSC |  |  |  |  |  |  |  |  | $ (31) | $ 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
[1] | These regulatory assets represent expenditures for which the MPSC has provided, or Consumers expects, recovery without a return on investment.

X
- Definition The amended annual renewable energy plan surcharge billed to customers. + References No definition available. + Details
Name: | cms_AmendedAnnualRenewableEnergyPlanSurchargeBilledToCustomers
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount that Consumers paid to transfer ownership and responsibility for the Big Rock ISFSI + References No definition available. + Details
Name: | cms_AmountPaidToTransferOwnershipAndResponsibility
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The annual amount by which the renewable energy plan surcharge billed to customers will be reduced + References No definition available. + Details
Name: | cms_AnnualAmountOfReductionOfRenewableEnergyPlanSurchargeBilledToCustomers
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The annual rate increase authorized by the MPSC. + References No definition available. + Details
Name: | cms_AnnualRateIncreaseAuthorized
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The annual rate increase requested by Consumers. + References No definition available. + Details
Name: | cms_AnnualRateIncreaseRequested
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition The amount the MPSC authorized Consumers to collect for its uncollectible expense tracking mechanism. + References No definition available. + Details
Name: | cms_AuthorizedRecovery
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The contribution to fund decommissioning costs. + References No definition available. + Details
Name: | cms_ContributionToFundDecommissioningCosts
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The difference between the annual rate increase authorized and self-implemented annual rate increase. + References No definition available. + Details
Name: | cms_DifferenceBetweenAnnualRateIncreaseAuthorizedAndSelfImplementedAnnualRateIncrease
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Energy optimization incentive to be requested for achieving electric and gas savings targets. + References No definition available. + Details
Name: | cms_EnergyOptimizationIncentiveToBeRequested
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 Nuclear fuel storage costs incurred by Consumers as a result of the DOE's failure to accept spent nuclear fuel. + References No definition available. + Details
Name: | cms_NuclearFuelStorageCostsIncurred
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The percentage of the difference between the level of expense included in rates and actual expense that will be collected or refunded. + References No definition available. + Details
Name: | cms_PercentageOfDifferenceBetweenRateBaseExpenseAndActualExpenseToCollectRefund
Namespace Prefix: | cms_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percent of Consumers' energy optimization savings targets achieved during 2011. + References No definition available. + Details
Name: | cms_PercentOfSavingsTargetAchieved
Namespace Prefix: | cms_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The proposed amended annual renewable energy plan surcharge billed to customers. + References No definition available. + Details
Name: | cms_ProposedAmendedAnnualRenewableEnergyPlanSurchargeBilledToCustomers
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The annual amount by which the renewable energy plan surcharge billed to customers will be reduced. + References No definition available. + Details
Name: | cms_ProposedAnnualAmountOfReductionOfRenewableEnergyPlanSurchargeBilledToCustomers
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The portion of the settlement proceeds Consumers has requested to use as recovery for its Big Rock Nuclear Decommissioning And Related Costs regulatory asset. + References No definition available. + Details
Name: | cms_ProposedRecoveryOfRegulatoryAsset
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Proposed Refund Of Spent Nuclear Fuel Disposal Costs Collected + References No definition available. + Details
Name: | cms_ProposedRefundOfSpentNuclearFuelDisposalCostsCollected
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The rate of return on equity authorized by the MPSC. + References No definition available. + Details
Name: | cms_RateOfReturnOnEquityAuthorized
Namespace Prefix: | cms_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The rate of return on equity requested by Consumers. + References No definition available. + Details
Name: | cms_RateOfReturnOnEquityRequested
Namespace Prefix: | cms_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The remaining portion of the settlement proceeds received from the DOE. + References No definition available. + Details
Name: | cms_RemainingPortionOfLitigationSettlement
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount for which Consumers 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 Revenue collected in excess of the costs incurred to decommission, plus interest, and for which the MPSC ordered a refund. + References No definition available. + Details
Name: | cms_RevenueCollectedInExcessOfCostsToDecommissionPlusInterest
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Current regulatory liabilities generally represent obligations to make refunds to customers for various reasons including overpayment. + References No definition available. + Details
Name: | us-gaap_CustomerRefundLiabilityCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition This element represents the gross amount awarded, to be received by, or to be remitted to the entity in settlement of litigation occurring during the period. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 9, 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 340 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382 + Details
Name: | us-gaap_RegulatoryAssetsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 11 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_RegulatoryLiabilityCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant