Public Utilitiies Requested Investment Recovery Mechanism

No definition available.

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- Definition

Energy optimization incentive requested for achieving electric and gas savings targets.

+ References

No definition available.

+ Details

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Namespace Prefix:	cms_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

+ Details

Name:	us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix:	us-gaap_
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Amount of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency.

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No definition available.

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Name:	us-gaap_PublicUtilitiesInterimRateIncreaseDecreaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

- Definition

Percentage of public utility's requested return on equity.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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- Details

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- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=cms_ElectricRateCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=cms_PlannedInvestments2016Member
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- Details

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- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=cms_GasRateCaseMember
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Regulatory Matters (Narrative) (Details) - Consumers Energy Company [Member] - USD ($) $ in Millions	1 Months Ended			6 Months Ended
	Jan. 31, 2015	Dec. 31, 2014	Jul. 31, 2014	Jun. 30, 2015	May. 31, 2015
Public Utilities, General Disclosures [Line Items]
Energy optimization incentive requested for exceeding savings targets					$ 17
Electric Rate Case [Member]
Public Utilities, General Disclosures [Line Items]
Annual rate increase requested		$ 163
Rate of return on equity requested		10.70%
Annual rate increase self-implemented				$ 110
Electric Rate Case [Member] \| 2016 and 2017 Planned Investments [Member]
Public Utilities, General Disclosures [Line Items]
Investment recovery mechanism requested		$ 163
Electric Rate Case [Member] \| 2018 Planned Investments [Member]
Public Utilities, General Disclosures [Line Items]
Investment recovery mechanism requested		$ 78
Gas Rate Case [Member]
Public Utilities, General Disclosures [Line Items]
Annual rate increase requested			$ 88
Annual rate increase authorized	$ 45
Rate of return on equity authorized	10.30%