XML 56 R81.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Plant, Property, and Equipment (Schedule of Finance Leases and Other Financing Obligations) (Details) - Consumers Energy Company - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018
Finance Leases and Other Financing Obligations, Rollforward [Roll Forward] |  |
Balance at beginning of period | $ 309 | $ 312
Additions | 26 | 0
Net retirements and other adjustments | 5 | (3)
Balance at end of period | 340 | 309
Less accumulated depreciation and amortization | $ 239 | $ 212

X
- Definition Finance Lease Asset, Net Retirements And Adjustments + References No definition available. + Details
Name: | cms_FinanceLeaseAssetNetRetirementsAndAdjustments
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Finance Lease Assets, Additions + References No definition available. + Details
Name: | cms_FinanceLeaseAssetsAdditions
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Finance Lease Right-Of-Use Asset, Accumulated Amortization + References No definition available. + Details
Name: | cms_FinanceLeaseRightOfUseAssetAccumulatedAmortization
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Finance Lease, Right-Of-Use Asset, Before Accumulated Amortization + References No definition available. + Details
Name: | cms_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_MovementInPropertyPlantAndEquipmentRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=cms_ConsumersEnergyCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |