Stock-Based Compensation (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation arrangements plan term	10 years
Number of shares authorized (in shares)	6,500,000
Shares available for grant (in shares)	5,927,297
Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation arrangements plan term	10 years
Number of shares authorized (in shares)	6,500,000
Shares available for grant (in shares)	5,927,297
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	0.00%
Minimum \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	200.00%
Maximum \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	200.00%
Performance-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	38 months
Vesting period	3 years
Performance-based awards \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	38 months
Vesting period	3 years
Performance-based awards \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	36 months
Performance-based awards \| Minimum \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	36 months
Market-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Vesting period	3 years
Market-based awards \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Vesting period	3 years
Time-lapse awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Time-lapse awards \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	1 year
Shares forfeited (in shares)	0
Restricted stock units \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	1 year
Shares forfeited (in shares)	0
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares forfeited (in shares)	22,264
Unrecognized compensation cost \| $	$ 24.1
Unrecognized compensation cost recognition period	2 years
Restricted stock \| Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares forfeited (in shares)	21,780
Unrecognized compensation cost \| $	$ 22.9
Unrecognized compensation cost recognition period	2 years

Deferred Compensation Arrangements Plan Term

No definition available.

Name:	cms_DeferredCompensationArrangementsPlanTerm
Namespace Prefix:	cms_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of initial grant of equity-based compensation awards earned depending on the outcome of the market condition or performance condition.

+ References

No definition available.

+ Details

Name:	cms_PercentOfInitialGrantIssuedOnVestingDate
Namespace Prefix:	cms_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- 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_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares authorized for issuance under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=cms_ConsumersEnergyCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=cms_MarketBasedRestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=cms_TimeLapsedRestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: