Accrual For Environmental Loss Contingencies, Net Of Discount

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- Definition

Accrual For Environmental Loss Contingencies, Reversed, Amortization Period

+ References

No definition available.

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- Definition

Asset Retirement Obligation And Accrual For Environmental Loss Contingencies

+ References

No definition available.

+ Details

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- Definition

Environmental Loss Contingencies, Regulatory Item

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

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- Definition

Number Of Coal Mine Asset Retirement Obligations Revised

+ References

No definition available.

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- Definition

The number of mine pits in final reclamation.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/recommendedDisclosureRef
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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
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- Definition

Undiscounted amount of the accrual for environmental loss contingencies.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

Increase (decrease) in the accrual for environmental loss contingencies during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
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- Definition

Amount of increase (decrease) in asset retirement obligations.

+ References

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ASSET RETIREMENT AND ENVIRONMENTAL RECLAMATION OBLIGATIONS - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2022 USD ($)	Dec. 31, 2023 USD ($) pit asset_retirement_obligation	Dec. 31, 2022 USD ($)
Asset Retirement Obligation And Accrual For Environmental Loss Contingencies [Line Items]
Number of coal mine asset retirement obligations revised \| asset_retirement_obligation		2
Increase (decrease) in asset retirement obligations			$ 36.8
Environmental Loss Contingency, Statement Of Financial Position, Extensible Enumeration, Not Disclosed Flag		environmental remediation liability
Colowyo Mine Pits - Final Reclamation
Asset Retirement Obligation And Accrual For Environmental Loss Contingencies [Line Items]
Number of mine pits in final reclamation \| pit		2
Colowyo Mine Pits - Increased AROs
Asset Retirement Obligation And Accrual For Environmental Loss Contingencies [Line Items]
Increase (decrease) in asset retirement obligations		$ 25.5
Colowyo Mine Pits - Decreased AROs
Asset Retirement Obligation And Accrual For Environmental Loss Contingencies [Line Items]
Increase (decrease) in asset retirement obligations		(1.4)
New Horizon Mine
Asset Retirement Obligation And Accrual For Environmental Loss Contingencies [Line Items]
Increase (decrease) in environmental reclamation obligations	$ 44.9
Environmental reclamation obligations		67.3
Discounted basis of environmental reclamation obligation		$ 36.8
Discount rate of environmental reclamation obligations (as a percent)		3.25%
Undiscounted future cash outflows of environmental reclamation obligations		$ 57.9
Regulatory item recognized		$ 44.9
Amortization period for portion of environmental reclamation obligations reversed		25 years