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Plant, Property, and Equipment (Public Utilities Property Plant and Equipment Schedule of Composite Depreciation Rate Table) (Details) - Consumers Energy Company | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Electric utility property |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Composite depreciation rate | 3.90% | 3.90% | 3.90%
Gas utility property |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Composite depreciation rate | 2.90% | 2.90% | 2.90%
Other property |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Composite depreciation rate | 9.80% | 10.00% | 10.10%

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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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