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

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-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

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 2
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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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-Paragraph 2
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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ 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
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- Definition

Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ 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
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- 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.

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- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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-Publisher FASB
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-Topic 718
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- 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.

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Stock-Based Compensation (Schedule Of Restricted Stock Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of Shares
Granted (in shares)	527,400
Consumers Energy Company
Number of Shares
Granted (in shares)	504,755
Restricted stock
Number of Shares
Granted (in shares)	512,326
Vested (in shares)	(551,897)
Forfeited (in share)	(329,874)
Weighted-Average Grant Date Fair Value per Share
Granted (in dollars per share)	$ 45.56	$ 43.57	$ 26.49
Vested (in dollars per share)	30.98
Forfeitured (in dollars per share)	$ 51.22
Restricted stock \| Consumers Energy Company
Number of Shares
Granted (in shares)	490,346
Vested (in shares)	(532,833)
Forfeited (in share)	(314,056)
Weighted-Average Grant Date Fair Value per Share
Granted (in dollars per share)	$ 45.53	43.57	26.51
Vested (in dollars per share)	31.04
Forfeitured (in dollars per share)	$ 51.22
Restricted stock units
Number of Shares
Granted (in shares)	15,074
Vested (in shares)	(15,234)
Forfeited (in share)	0
Weighted-Average Grant Date Fair Value per Share
Granted (in dollars per share)	$ 49.76	50.35	41.77
Vested (in dollars per share)	$ 49.24
Restricted stock units \| Consumers Energy Company
Number of Shares
Granted (in shares)	14,409
Vested (in shares)	(14,517)
Forfeited (in share)	0
Weighted-Average Grant Date Fair Value per Share
Granted (in dollars per share)	$ 49.70	$ 51.15	$ 42.01
Vested (in dollars per share)	$ 49.50
Restricted Stock and Restricted Stock Units
Number of Shares
Nonvested, at beginning of period (in shares)	1,186,962
Nonvested, at end of period (in shares)	817,357	1,186,962
Weighted-Average Grant Date Fair Value per Share
Weighted-average grant date fair value per share, at beginning of period (in dollars per share)	$ 44.56
Weighted-average grant date fair value per share, at end of period (in dollars per share)	$ 51.68	$ 44.56
Restricted Stock and Restricted Stock Units \| Consumers Energy Company
Number of Shares
Nonvested, at beginning of period (in shares)	1,138,182
Nonvested, at end of period (in shares)	781,531	1,138,182
Weighted-Average Grant Date Fair Value per Share
Weighted-average grant date fair value per share, at beginning of period (in dollars per share)	$ 44.57
Weighted-average grant date fair value per share, at end of period (in dollars per share)	$ 51.73	$ 44.57