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Plant, Property, and Equipment (Schedule of Capital Leased Assets) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Capital Leases, Assets, Rollforward [Roll Forward] |  |  |
Additions | $ 2,081 | $ 1,722 | $ 1,633
Consumers Energy Company |  |  |
Capital Leases, Assets, Rollforward [Roll Forward] |  |  |
Additions | 1,825 | 1,683 | 1,618
Accumulated amortization | 212 | 193 |
Consumers Energy Company | Assets Held under Capital Leases |  |  |
Capital Leases, Assets, Rollforward [Roll Forward] |  |  |
Balance at beginning of period | 312 | 310 |
Additions | 0 | 3 |
Net retirements and other adjustments | (3) | (1) |
Balance at end of period | $ 309 | $ 312 | $ 310

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- Definition Capital Leases, Assets, Rollforward [Roll Forward] + References No definition available. + Details
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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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=84164758&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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 2) -URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=84164758&loc=d3e45014-112735 + 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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