XML 104 R57.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Significant Accounting Policies (Details) | 12 Months Ended
--- | ---
Dec. 31, 2016
Minimum [Member] | EnerBank [Member] |
Significant Accounting Policies [Line Items] |
Same as cash, fee recognition period | 3 months
Authorized contractor, fee recognition period | 1 year
Maximum [Member] | Consumers Energy Company [Member] |
Significant Accounting Policies [Line Items] |
Financial incentive as percentage of energy optimization program spending | 15.00%
Energy optimization spending limit | 2.00%
Maximum [Member] | EnerBank [Member] |
Significant Accounting Policies [Line Items] |
Same as cash, fee recognition period | 24 months
Authorized contractor, fee recognition period | 12 years

X
- Definition Authorized contractor, fee recognition period + References No definition available. + Details
Name: | cms_AuthorizedContractorFeeRecognitionPeriod
Namespace Prefix: | cms_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The limit, as a percentage of retail revenue, of energy optimization program spending. + References No definition available. + Details
Name: | cms_EnergyOptimizationSpendingLimit
Namespace Prefix: | cms_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Financial incentive as percentage of energy optimization program spending + References No definition available. + Details
Name: | cms_FinancialIncentiveAsPercentageOfEnergyOptimizationProgramSpending
Namespace Prefix: | cms_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Same as cash, fee recognition period + References No definition available. + Details
Name: | cms_SameAsCashFeeRecognitionPeriod
Namespace Prefix: | cms_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | cms_SignificantAccountingPoliciesLineItems
Namespace Prefix: | cms_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=cms_EnerBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=cms_ConsumersEnergyCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |