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v2.4.1.9

Related Party Transactions - Consumers (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Sep. 30, 2014 | Nov. 30, 2014
Related Party Transaction [Line Items] |  |  |  |  |
Purchased power - related parties | $ 90 cms_PurchasedPowerRelatedParties | $ 90 cms_PurchasedPowerRelatedParties | $ 87 cms_PurchasedPowerRelatedParties |  |
Accounts payable - related parties | 10 us-gaap_DueToRelatedPartiesCurrent | 10 us-gaap_DueToRelatedPartiesCurrent |  |  |
Consumers Energy Company [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Purchased power - related parties | 89 cms_PurchasedPowerRelatedParties / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember | 89 cms_PurchasedPowerRelatedParties / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember | 86 cms_PurchasedPowerRelatedParties / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember |  |
Accounts payable - related parties | 12 us-gaap_DueToRelatedPartiesCurrent / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember | 13 us-gaap_DueToRelatedPartiesCurrent / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember |  |  |
Investment Owned, Balance, Shares | 1.1 us-gaap_InvestmentOwnedBalanceShares / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember |  |  |  |
Investments | 38 us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember | 29 us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember |  |  |
Future purchase power, related parties |  |  |  | 3 cms_FuturePurchasePowerRelatedParties / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember |
Consumers Energy Company [Member] | Credit Agreement [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Maximum borrowing capacity |  |  |  |  | 300 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity / us-gaap_CreditFacilityAxis = us-gaap_LineOfCreditMember / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember
Amount outstanding | $ 0 us-gaap_LineOfCredit / us-gaap_CreditFacilityAxis = us-gaap_LineOfCreditMember / dei_LegalEntityAxis = cms_ConsumersEnergyCompanyMember |  |  |  |

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- Definition Future purchase power, related parties + References No definition available. + Details
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Balance Type: | debit
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- Definition Cost of electricity purchased from related parties and sold during the reporting period. + References No definition available. + Details
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Balance Type: | debit
Period Type: | duration

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- Definition Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(k)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph k -Subparagraph 1 -Article 4 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19 -Subparagraph a -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(a)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Balance held at close of period in number of shares. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-12C.Column B) -URI http://asc.fasb.org/extlink&oid=34726532&loc=d3e611225-123010 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 6 -Subparagraph (SX 210.12-14.Column B) -URI http://asc.fasb.org/extlink&oid=34726532&loc=d3e611322-123010 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-12.Column B) -URI http://asc.fasb.org/extlink&oid=34726532&loc=d3e611133-123010 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12C -Paragraph Column B -Article 12 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Paragraph Column B -Article 12 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 14 -Paragraph Column B -Article 12 + Details
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- Definition Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Details
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