XML 194 R43.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Accumulated Other Comprehensive Loss ("AOCL") (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2024
Additional financial information disclosures [Abstract] |
Components of Accumulated Other Comprehensive Loss |
Components of AOCL | 2024 |  | 2023
Defined benefit plan liabilities | $ | (107.0) |  |  | $ | (101.8) |
Unrealized gain on financial instruments | 1.4 |  |  | 1.6 |
Other comprehensive loss before income tax effect | (105.6) |  |  | (100.2) |
Income tax effect(1) | 2.3 |  |  | 2.3 |
Accumulated other comprehensive loss | $ | (103.3) |  |  | $ | (97.9) |
(1)The allocation of the income tax effect to the components of other comprehensive loss is as follows:
| 2024 |  | 2023
Defined benefit plan liabilities | $ | 2.6 |  |  | $ | 2.6 |
Unrealized loss on financial instruments | (0.3) |  |  | (0.3) |
The following table summarizes the changes in the accumulated balances for each component of AOCL:
| Defined benefit plan and other postretirement liabilities |  | Unrealized gain (loss) on financial instruments |  | Total, net of tax
Balance, December 31, 2021 | $ | (84.0) |  |  | $ | 1.7 |  |  | $ | (82.3) |
Other comprehensive income (loss) before reclassifications | (5.9) |  |  | — |  |  | (5.9) |
Net amount reclassified to net income (loss) | (5.7) |  |  | (0.1) |  |  | (5.8) |
Balance, December 31, 2022 | (95.6) |  |  | 1.6 |  |  | (94.0) |
Other comprehensive income (loss) before reclassifications | (10.1) |  |  | — |  |  | (10.1) |
Net amount reclassified to net income (loss) | 6.3 |  |  | (0.1) |  |  | 6.2 |
Balance, December 31, 2023 | (99.4) |  |  | 1.5 |  |  | (97.9) |
Other comprehensive income (loss) before reclassifications | (11.9) |  |  | — |  |  | (11.9) |
Net amount reclassified to net income (loss) | 6.7 |  |  | (0.2) |  |  | 6.5 |
Balance, December 31, 2024 | $ | (104.6) |  |  | $ | 1.3 |  |  | $ | (103.3) |
Reclassification out of AOCL | Reclassifications out of AOCL were included in the Consolidated Statements of Operations as follows:
|  |  |  | Year Ended December 31,
AOCL Components |  | Location |  | 2024 |  | 2023 |  | 2022
Defined benefit plan and other postretirement liabilities |  | Cost of goods sold |  | $ | (8.5) |  |  | $ | (1.0) |  |  | $ | 3.5 |
|  | Other income, net |  | — |  |  | — |  |  | (8.9) |
|  | Selling, general and administrative expenses |  | 1.1 |  |  | (0.2) |  |  | 3.3 |
|  | Other operating expense (income), net |  | 2.2 |  |  | (2.6) |  |  | (9.0) |
|  | Income tax expense |  | — |  |  | — |  |  | (0.3) |
|  | Net of tax |  | $ | (5.2) |  |  | $ | (3.8) |  |  | $ | (11.4) |
Gain (loss) on financial instruments |  | Cost of goods sold |  | $ | (0.2) |  |  | $ | (0.1) |  |  | $ | (0.2) |
|  | Income tax effect |  | $ | — |  |  | — |  |  | (0.1) |
|  | Net of tax |  | $ | (0.2) |  |  | $ | (0.1) |  |  | $ | (0.3) |

X
- Definition Additional financial information disclosures + References No definition available. + Details
Name: | cenx_AdditionalfinancialinformationdisclosuresAbstract
Namespace Prefix: | cenx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of information about items reclassified out of accumulated other comprehensive income (loss). + References No definition available. + Details
Name: | us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of accumulated other comprehensive income (loss). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482790/220-10-45-14A Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 830 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481674/830-30-50-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 830 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481694/830-30-45-20 + Details
Name: | us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration