XML 109 R80.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Pension and Other Postretirement Benefits - Weighted Average assumptions used in calculating benefit obligations (Details) | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
Pension |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rate | 5.19% | 5.50%
Rate of compensation increase, group 1 | 3.50% | 4.00%
Rate of compensation increase, group 2 |  | 3.50%
Measurement date | Dec. 31, 2023 | Dec. 31, 2022
OPEB |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Discount rate | 5.19% | 5.57%
Rate of compensation increase, group 1 | 3.50% | 4.00%
Rate of compensation increase, group 2 |  | 3.50%
Measurement date | Dec. 31, 2023 | Dec. 31, 2022

X
- Definition The maximum expected rate of compensation increases (for pay-related plans). + References No definition available. + Details
Name: | cenx_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncreaseAfterFiscalYear
Namespace Prefix: | cenx_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Measurement Date, Benefit Obligation + References No definition available. + Details
Name: | cenx_MeasurementDateBenefitObligation
Namespace Prefix: | cenx_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (k)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |