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Environmental Loss Contingency, Statement Of Financial Position, Extensible Enumeration, Not Disclosed Flag

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Number Of Former Manufactured Gas Plants

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Regulatory Asset, Estimate Of Shared Costs

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Total costs accrued as of the balance sheet date for environmental loss contingencies.

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Rate applied to the undiscounted amount of environmental loss contingencies to arrive at the present value recorded as of the balance sheet date.

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Undiscounted amount of the accrual for environmental loss contingencies.

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The proportionate share of interest (percent) in a jointly owned utility plant.

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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.

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The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

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Contingencies and Commitments (Narrative) (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2025 USD ($) facility	Dec. 31, 2022 USD ($)	Dec. 31, 2024 USD ($)
Loss Contingencies [Line Items]
Environmental Loss Contingency, Statement Of Financial Position, Extensible Enumeration, Not Disclosed Flag	recorded liability
Regulatory assets	$ 3,570		$ 3,569
Consumers Energy Company
Loss Contingencies [Line Items]
Regulatory assets	3,570		$ 3,569
Consumers Energy Company \| MGP sites
Loss Contingencies [Line Items]
Regulatory assets	$ 86
Consumers Energy Company \| Ludington
Loss Contingencies [Line Items]
Ownership share	51.00%
Consumers Energy Company \| Ludington Plant Overhaul Contract Dispute
Loss Contingencies [Line Items]
Damages sought		$ 15
Estimate of shared costs	$ 350
Bay Harbor
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 47
Discount rate	4.34%
Accrual for environmental loss contingencies, inflation rate	1.00%
Accrual for environmental loss contingencies, gross	$ 59
NREPA \| Electric Utility \| Consumers Energy Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	4
NREPA \| Minimum \| Electric Utility \| Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs	4
NREPA \| Maximum \| Electric Utility \| Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs	5
CERCLA Liability \| Consumers Energy Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	3
CERCLA Liability \| Minimum \| Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs	3
CERCLA Liability \| Maximum \| Consumers Energy Company
Loss Contingencies [Line Items]
Remediation and other response activity costs	8
MGP sites \| Consumers Energy Company
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 59
Number of former MGPs \| facility	23
Regulatory asset collection period	10 years