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Plant, Property, and Equipment (Schedule of Capital Leased Asssets) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Property, Plant and Equipment [Line Items] |  |  |  |
Capital Leased Assets, Gross, Additions | [1] | $ 1,741 | $ 1,616 | $ 1,408
Consumers Energy Company [Member] |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |
Capital Leased Assets, Gross, Additions | [1] | 1,694 | 1,612 | 1,403
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation |  | 152 | 143 |
Consumers Energy Company [Member] | Assets Held under Capital Leases [Member] |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |
Balance at beginning of period |  | 295 | 291 |
Capital Leased Assets, Gross, Additions |  | 17 | 7 |
Capital Leased Assets, Gross, Net retirements and other adjustments |  | (12) | (3) |
Balance at end of period |  | $ 300 | $ 295 | $ 291
[1] | Amounts include purchase of capital lease additions. Amounts also include a portion of Consumers' capital expenditures for plant and equipment attributable to both the electric and gas utility businesses.

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- Definition Amount before accumulated depreciation of leased 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 840 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6455314&loc=d3e45014-112735 + Details
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- Definition The total charge for the use of long-lived depreciable assets subject to a lease meeting the criteria for capitalization. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6455314&loc=d3e45014-112735 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 2) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 + Details
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- Definition Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
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- Definition Amount of divestiture of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
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