Guarantees And Other Contingencies [Line Items]

No definition available.

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- Definition

Annual contribution to be paid by counterparty to a renewable resources program.

+ References

No definition available.

+ Details

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- Definition

The price per MWh of available capacity that must be paid, in connection with an unconditional purchase obligation that has not been recognized for financial reporting purposes.

+ References

No definition available.

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- Definition

Unrecorded Unconditional Purchase Obligation, Fixed Energy Charge Per Mwh, Off-Peak

+ References

No definition available.

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- Definition

Unrecorded Unconditional Purchase Obligation, Fixed Energy Charge Per Mwh, On-Peak

+ References

No definition available.

+ Details

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- Definition

Maximum number of power units that may be acquired, in connection with an unconditional purchase obligation that has not been recognized for financial reporting purposes.

+ References

No definition available.

+ Details

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- Definition

The minimum number of units that must be purchased, in connection with unconditional purchase obligations that have not been recognized for financial reporting purposes.

+ References

No definition available.

+ Details

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- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

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Balance Type:	credit
Period Type:	instant

- Definition

Describe the approximate term of the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

+ Details

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121559207&loc=d3e25336-109308

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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Period Type:	instant

- Definition

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

+ Details

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Period Type:	instant

- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121559207&loc=d3e25336-109308

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount purchased during the period under an unrecorded unconditional purchase obligation (for example, under the take-or-pay or throughput contract).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121559207&loc=d3e25336-109308

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- Details

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- Details

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Contingencies and Commitments (Guarantees) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / MW $ / MWh MW	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jul. 31, 2020
Variable Interest Entity, Primary Beneficiary \| Aviator Wind Class B Membership
Guarantees And Other Contingencies [Line Items]
Ownership percentage				49.00%
Guarantees
Guarantees And Other Contingencies [Line Items]
Expiration Date	indefinite
Maximum Obligation	$ 30
Carrying Amount	$ 0
Guarantees \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Expiration Date	indefinite
Maximum Obligation	$ 30
Carrying Amount	$ 0
Indemnification Agreement From Purchase Of Variable Interest Entity
Guarantees And Other Contingencies [Line Items]
Expiration Date	indefinite
Maximum Obligation	$ 349
Carrying Amount	$ 0
Indemnity Obligations From Stock And Asset Sales Agreements
Guarantees And Other Contingencies [Line Items]
Expiration Date	indefinite
Maximum Obligation	$ 153
Carrying Amount	2
Tax And Other Indemnity Obligations \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Carrying Amount	1
MCV PPA \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Total	2,815
2021	349
2022	340
2023	358
2024	376
2025	329
Beyond 2025	$ 1,063
PPA minimum quantity required \| MW	1,240
PPA fixed energy charge per MWh, on-peak (in dollars per MWh) \| $ / MWh	6.30
PPA fixed energy charge per MWh, off-peak (in dollars per MWh) \| $ / MWh	6.00
Annual contribution to renewable resources program by counterparty	$ 5
Purchases	$ 298	$ 318	$ 353
MCV PPA \| Consumers Energy Company \| Year End Through March 2025
Guarantees And Other Contingencies [Line Items]
PPA capacity charge per MWh (in dollars per MWh) \| $ / MW	10.14
MCV PPA \| Consumers Energy Company \| March 2025 Through Termination
Guarantees And Other Contingencies [Line Items]
PPA capacity charge per MWh (in dollars per MWh) \| $ / MW	5.00
Palisades PPA \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Total	$ 517
2021	398
2022	119
2023	0
2024	0
2025	0
Beyond 2025	0
Purchases	403	395	375
Related-party PPAs \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Total	318
2021	58
2022	58
2023	58
2024	58
2025	39
Beyond 2025	47
Other PPAs \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Total	5,248
2021	252
2022	274
2023	315
2024	350
2025	364
Beyond 2025	3,693
Purchases	327	$ 336	$ 350
Total PPAs \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Total	8,898
2021	1,057
2022	791
2023	731
2024	784
2025	732
Beyond 2025	4,803
Other
Guarantees And Other Contingencies [Line Items]
Total	3,179
2021	1,391
2022	871
2023	265
2024	199
2025	171
Beyond 2025	282
Other \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Total	2,605
2021	1,333
2022	777
2023	207
2024	154
2025	130
Beyond 2025	$ 4
Palisades Power Purchase Agreement \| Financing Obligation \| Consumers Energy Company
Guarantees And Other Contingencies [Line Items]
Annual average capacity (in MW) \| MW	798