XML 128 R98.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Retirement Benefits (Schedule of SERP Trust Assets, ABO and Contributions) (Details) - DB SERP - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
ABO | $ 105 | $ 115
Consumers Energy Company |  |
Defined Benefit Plan Disclosure [Line Items] |  |
ABO | 76 | 83
Trust assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Trust assets | 127 | 132
Trust assets | Consumers Energy Company |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Trust assets | $ 95 | $ 98

X
- Definition Defined Benefit Plan, Trust Assets + References No definition available. + Details
Name: | cms_DefinedBenefitPlanTrustAssets
Namespace Prefix: | cms_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=cms_DbSerpTrustAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |