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Plant, Property, and Equipment (Public Utilities Property Plant and Equipment Schedule of Composite Depreciation Rate Table) (Details) - Consumers Energy Company [Member] | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Electric Utility Property [Member] |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service | 3.50% | 3.50% | 3.50%
Gas Utility Property [Member] |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service | 2.80% | 2.80% | 2.80%
Other property [Member] |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service | 8.70% | 7.70% | 7.00%

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- Definition Composite depreciation rate for public utility plants in service. + References No definition available. + Details
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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. + References No definition available. + Details
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