XML 63 R52.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Derivatives, Hedging Programs and Other Financial Instruments, Material Derivative Positions (Details) mmlbs in Millions | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 EUR (€) MMBTU mmlbs
--- | --- | --- | --- | --- | ---
Not Designated as Hedging Instrument | Option on Securities | Purchase |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount |  |  |  |  | 13.4
Not Designated as Hedging Instrument | Aluminum | Purchase |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount |  |  |  |  | 151.9
Not Designated as Hedging Instrument | Aluminum | Sales |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount |  |  |  |  | 1.8
Not Designated as Hedging Instrument | Midwest premium swap contracts | Purchase |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount |  |  |  |  | 150.1
Not Designated as Hedging Instrument | Natural Gas | Purchase |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount | MMBTU |  |  |  |  | 3,650,000
Designated as Hedging Instrument | Alloy Metal Hedge | Purchase |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount |  |  |  |  | 4.6
Designated as Hedging Instrument | Foreign Exchange Contract | Purchase |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Notional Amount | € |  |  |  |  | € 301,304
Scenario, Forecast | Natural Gas |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage | 39.00% | 71.00% | 71.00% | 72.00% |
Scenario, Forecast | Electricity Member |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Derivative, Nonmonetary Notional Amount, Percent of Required Need, Coverage | 18.00% | 55.00% | 55.00% | 54.00% |

X
- Definition Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNonmonetaryNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:monetaryItemType
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_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of expected requirements covered by the aggregate notional amount of derivative contracts expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract as a percentage of expected need. + References No definition available. + Details
Name: | us-gaap_DerivativeNonmonetaryNotionalAmountPercentOfRequiredNeedCoverage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_OptionOnSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_LongMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=kalu_AluminumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_ShortMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=kalu_MidwestPremiumSwapContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=kalu_NaturalGasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=kalu_AlloyMetalHedgeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=kalu_ElectricityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |