Stock-Based Compensation (Narrative) (Details)	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangements Plan Term	5 years
Number of shares authorized	6,000,000
Maximum shares issuable per employee	500,000
Shares available for grant	2,068,751
Consumers Energy Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Arrangements Plan Term	5 years
Number of shares authorized	6,000,000
Maximum shares issuable per employee	500,000
Shares available for grant	2,068,751
TSR Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Type of award grant, percentage	75.00%	75.00%
Service period	3 years
TSR Restricted Stock [Member] \| Consumers Energy Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Type of award grant, percentage	75.00%	75.00%
Service period	3 years
TSR Restricted Stock [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of Initial Grant Issued on Vesting Date	0.00%
TSR Restricted Stock [Member] \| Minimum [Member] \| Consumers Energy Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of Initial Grant Issued on Vesting Date	0.00%
TSR Restricted Stock [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of Initial Grant Issued on Vesting Date	200.00%
TSR Restricted Stock [Member] \| Maximum [Member] \| Consumers Energy Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of Initial Grant Issued on Vesting Date	200.00%
Time-Lapsed Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Type of award grant, percentage	25.00%	25.00%
Vesting period	3 years
Time-Lapsed Restricted Stock [Member] \| Consumers Energy Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Type of award grant, percentage	25.00%	25.00%
Vesting period	3 years

Deferred Compensation Arrangements Plan Term

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

The highest quantity of shares an employee can be awarded under the plan per period.

+ References

No definition available.

+ Details

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- Definition

Share Based Compensation Arrangement By Share Based Payment Award, Percentage

+ References

No definition available.

+ Details

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- 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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- 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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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