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

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

+ Details

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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

+ Details

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- Definition

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

+ 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

+ Details

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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 Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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

+ Details

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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

+ Details

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Stock-Based Compensation (Narrative) (Details)	12 Months Ended
Stock-Based Compensation (Narrative) (Details)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred Compensation Arrangements Plan Term	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	6,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee	500,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,972,977
Consumers Energy Company [Member]
Deferred Compensation Arrangements Plan Term	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	6,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee	500,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,972,977
Stock Options [Member] \| Maximum [Member]
Deferred Compensation Arrangements Plan Term	10 years 1 month
Stock Options [Member] \| Maximum [Member] \| Consumers Energy Company [Member]
Deferred Compensation Arrangements Plan Term	10 years 1 month
TSR Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period	3 years
Share Based Compensation Arrangement By Share Based Payment Award, Percentage	75.00%	75.00%	67.00%
TSR Restricted Stock [Member] \| Consumers Energy Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period	3 years
Share Based Compensation Arrangement By Share Based Payment Award, Percentage	75.00%	75.00%	67.00%
TSR Restricted Stock [Member] \| Minimum [Member]
Percent of Initial Grant Issued on Vesting Date	0.00%
TSR Restricted Stock [Member] \| Minimum [Member] \| Consumers Energy Company [Member]
Percent of Initial Grant Issued on Vesting Date	0.00%
TSR Restricted Stock [Member] \| Maximum [Member]
Percent of Initial Grant Issued on Vesting Date	200.00%
TSR Restricted Stock [Member] \| Maximum [Member] \| Consumers Energy Company [Member]
Percent of Initial Grant Issued on Vesting Date	200.00%
Time-Lapsed Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Share Based Compensation Arrangement By Share Based Payment Award, Percentage	25.00%	25.00%	33.00%
Time-Lapsed Restricted Stock [Member] \| Consumers Energy Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Share Based Compensation Arrangement By Share Based Payment Award, Percentage	25.00%	25.00%	33.00%