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Plant, Property, and Equipment (Public Utilities Property Plant and Equipment Schedule of Accumulated Depreciation and Amortization) (Details) - USD ($) $ in Millions | Dec. 31, 2015 | Dec. 31, 2014
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Public Utility, Property, Plant and Equipment [Line Items] |  |
Accumulated Depreciation, Depletion and Amortization | $ 5,747 | $ 5,415
Consumers Energy Company [Member] |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Accumulated depreciation and amortization | 5,676 | 5,346
Utility Plant Assets [Member] |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Accumulated Depreciation, Depletion and Amortization | 5,674 | 5,345
Utility Plant Assets [Member] | Consumers Energy Company [Member] |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Accumulated depreciation and amortization | 5,674 | 5,345
Non-Utility Plant Assets [Member] |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Accumulated Depreciation, Depletion and Amortization | 73 | 70
Non-Utility Plant Assets [Member] | Consumers Energy Company [Member] |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |
Accumulated depreciation and amortization | $ 2 | $ 1

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- Definition Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.14) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Period end book value of accumulated depreciation on property, plant and equipment (PPE) that is owned by the regulated operations of the public utility. + 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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