$KALU
KAISER ALUMINUM CORP Stock $kalu

$kalu Overview Financials Valuation SEC Filings Company Website

2019 Q4 Form 10-K Financial Statement

#000081159620000010 Filed on February 25, 2020

Income Statement

Concept	2019 Q4	2019 Q3	2019 Q2
Revenue	$368.7M	$374.9M	$375.3M
YoY Change	-5.32%	-4.63%	-9.65%
Cost Of Revenue	$298.0M	$298.6M	$303.5M
YoY Change	-6.08%	-7.64%	-11.62%
Gross Profit	$70.70M	$76.30M	$71.80M
YoY Change	-1.94%	9.31%	-0.28%
Gross Profit Margin	19.18%	20.35%	19.13%
Selling, General & Admin	$22.30M	$23.30M	$27.20M
YoY Change	-0.45%	-2.51%	3.03%
% of Gross Profit	31.54%	30.54%	37.88%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$12.80M	$12.30M	$12.10M
YoY Change	11.3%	11.82%	11.01%
% of Gross Profit	18.1%	16.12%	16.85%
Operating Expenses	$35.90M	$35.60M	$39.40M
YoY Change	1.99%	2.01%	5.63%
Operating Profit	$9.600M	$40.70M	$32.40M
YoY Change	-73.98%	16.62%	-6.63%
Interest Expense	-$5.700M	$5.800M	$5.800M
YoY Change	42.5%	1.75%	1.75%
% of Operating Profit	-59.38%	14.25%	17.9%
Other Income/Expense, Net	-$1.600M	-$800.0K	-$100.0K
YoY Change	-44.83%	-214.29%	-80.0%
Pretax Income	-$18.00M	$34.10M	$26.50M
YoY Change	-160.0%	14.05%	-7.02%
Income Tax	-$7.400M	$8.700M	$7.300M
% Of Pretax Income		25.51%	27.55%
Net Earnings	-$10.60M	$25.40M	$19.20M
YoY Change	-144.92%	17.05%	-7.25%
Net Earnings / Revenue	-2.87%	6.78%	5.12%
Basic Earnings Per Share	-$0.66	$1.59	$1.19
Diluted Earnings Per Share	-$0.66	$1.57	$1.18
COMMON SHARES
Basic Shares Outstanding	15.88M shares	15.96M	16.06M
Diluted Shares Outstanding		16.13M	16.24M

Balance Sheet

Concept	2019 Q4	2019 Q3	2019 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$343.0M	$197.4M	$146.8M
YoY Change	111.34%	8.05%	-37.77%
Cash & Equivalents	$264.3M	$172.1M	$122.4M
Short-Term Investments	$78.70M	$168.1M	$114.6M
Other Short-Term Assets	$19.40M	$18.40M	$21.70M
YoY Change	2.65%	-23.97%	-25.17%
Inventory	$177.6M	$192.5M	$231.1M
Prepaid Expenses
Receivables	$167.1M	$188.1M	$178.1M
Other Receivables	$18.10M	$26.10M	$25.10M
Total Short-Term Assets	$779.8M	$668.6M	$649.7M
YoY Change	18.76%	-0.65%	-7.82%
LONG-TERM ASSETS
Property, Plant & Equipment	$622.0M	$614.3M	$613.8M
YoY Change	1.67%	3.17%	5.07%
Goodwill	$18.80M	$44.00M	$44.00M
YoY Change	-57.27%	1.38%	134.04%
Intangibles
YoY Change
Long-Term Investments
YoY Change
Other Assets	$38.40M	$36.50M	$41.30M
YoY Change	-0.52%	-6.41%	2.74%
Total Long-Term Assets	$746.4M	$757.7M	$772.4M
YoY Change	-2.14%	0.62%	7.43%
TOTAL ASSETS
Total Short-Term Assets	$779.8M	$668.6M	$649.7M
Total Long-Term Assets	$746.4M	$757.7M	$772.4M
Total Assets	$1.526B	$1.426B	$1.422B
YoY Change	7.53%	0.02%	-0.12%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$92.00M	$93.80M	$101.3M
YoY Change	-24.22%	-22.09%	-23.26%
Accrued Expenses	$71.00M	$72.80M	$68.60M
YoY Change	-8.51%	13.93%	24.95%
Deferred Revenue	$200.0K
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$1.200M	$1.200M	$1.200M
YoY Change
Total Short-Term Liabilities	$170.4M	$175.8M	$178.9M
YoY Change	-17.08%	-8.68%	-7.83%
LONG-TERM LIABILITIES
Long-Term Debt	$492.6M	$371.1M	$370.9M
YoY Change	32.99%	0.24%	0.24%
Other Long-Term Liabilities	$67.00M	$26.30M	$24.70M
YoY Change	0.9%	1.94%	-0.4%
Total Long-Term Liabilities	$559.6M	$397.4M	$395.6M
YoY Change	28.11%	0.35%	0.2%
TOTAL LIABILITIES
Total Short-Term Liabilities	$170.4M	$175.8M	$178.9M
Total Long-Term Liabilities	$559.6M	$397.4M	$395.6M
Total Liabilities	$792.3M	$674.9M	$675.8M
YoY Change	16.7%	1.72%	1.96%
SHAREHOLDERS EQUITY
Retained Earnings	$172.8M	$193.0M	$177.3M
YoY Change	15.05%	42.33%	44.03%
Common Stock	$1.063B	$1.062B	$1.059B
YoY Change	0.34%	0.39%	0.43%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$463.4M	$460.1M	$448.1M
YoY Change	10.2%	17.7%	18.54%
Treasury Stock Shares	$6.683M	6.650M shares	6.521M shares
Shareholders Equity	$733.9M	$751.4M	$746.3M
YoY Change
Total Liabilities & Shareholders Equity	$1.526B	$1.426B	$1.422B
YoY Change	7.53%	0.02%	-0.12%

Cashflow Statement

Concept	2019 Q4	2019 Q3	2019 Q2
OPERATING ACTIVITIES
Net Income	-$10.60M	$25.40M	$19.20M
YoY Change	-144.92%	17.05%	-7.25%
Depreciation, Depletion And Amortization	$12.80M	$12.30M	$12.10M
YoY Change	11.3%	11.82%	11.01%
Cash From Operating Activities	$78.40M	$83.40M	$47.70M
YoY Change	107.96%	192.63%	-17.62%
INVESTING ACTIVITIES
Capital Expenditures	-$19.50M	-$10.80M	-$16.30M
YoY Change	-6.7%	-82.18%	1.24%
Acquisitions
YoY Change
Other Investing Activities	-$53.00M	-$800.0K	-$2.400M
YoY Change	-202.12%	-94.74%	-121.05%
Cash From Investing Activities	-$72.50M	-$11.60M	-$18.70M
YoY Change	-333.87%	-84.7%	297.87%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	86.20M	-22.20M	-21.50M
YoY Change	-325.65%	-0.89%	-4.87%
NET CHANGE
Cash From Operating Activities	78.40M	83.40M	47.70M
Cash From Investing Activities	-72.50M	-11.60M	-18.70M
Cash From Financing Activities	86.20M	-22.20M	-21.50M
Net Change In Cash	92.10M	49.60M	7.500M
YoY Change	201.97%	-171.16%	-75.49%
FREE CASH FLOW
Cash From Operating Activities	$78.40M	$83.40M	$47.70M
Capital Expenditures	-$19.50M	-$10.80M	-$16.30M
Free Cash Flow	$97.90M	$94.20M	$64.00M
YoY Change	67.06%	5.72%	-13.51%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2019	dei	Amendment Flag AmendmentFlag	false
CY2019	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2019	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2019	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
CY2019	dei	Entity Central Index Key EntityCentralIndexKey	0000811596
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CY2018Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	90000000	shares
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	90000000	shares
CY2018Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	22471705	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	22550827	shares
CY2018Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	16234603	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	15868304	shares
CY2018Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2019Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	5000000	shares
CY2018Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2019Q4	us-gaap	Preferred Stock Shares Issued PreferredStockSharesIssued	0	shares
CY2018Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2019Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2018Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	6237102	shares
CY2019Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	6682523	shares
CY2019	dei	Document Type DocumentType	10-K
CY2019	dei	Document Annual Report DocumentAnnualReport	true
CY2019	dei	Document Period End Date DocumentPeriodEndDate	2019-12-31
CY2019	dei	Document Transition Report DocumentTransitionReport	false
CY2019	dei	Entity File Number EntityFileNumber	1-09447
CY2019	dei	Entity Registrant Name EntityRegistrantName	KAISER ALUMINUM CORPORATION
CY2019	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2019	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	94-3030279
CY2019	dei	Entity Address Address Line1 EntityAddressAddressLine1	27422 Portola Parkway
CY2019	dei	Entity Address Address Line2 EntityAddressAddressLine2	Suite 200
CY2019	dei	Entity Address City Or Town EntityAddressCityOrTown	Foothill Ranch
CY2019	dei	Entity Address State Or Province EntityAddressStateOrProvince	CA
CY2019	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	92610-2831
CY2019	dei	City Area Code CityAreaCode	(949)
CY2019	dei	Local Phone Number LocalPhoneNumber	614-1740
CY2019	dei	Security12b Title Security12bTitle	Common stock, par value $0.01 per share
CY2019	dei	Trading Symbol TradingSymbol	KALU
CY2019	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2019	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2019	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2019	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2019	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2019	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2019	dei	Entity Small Business EntitySmallBusiness	false
CY2019	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2019	dei	Entity Shell Company EntityShellCompany	false
CY2019Q2	dei	Entity Public Float EntityPublicFloat	1500000000	USD
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CY2019Q4	us-gaap	Assets Assets	1526200000	USD
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CY2018Q4	us-gaap	Liabilities Current LiabilitiesCurrent	205500000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	25200000	USD
CY2018Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	0	USD
CY2019Q4	kalu	Net Liability In Respect Of Veba NetLiabilityInRespectOfVeba	32600000	USD
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CY2019Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	4500000	USD
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CY2019Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2018Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
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CY2019	us-gaap	Net Income Loss NetIncomeLoss	62000000.0	USD
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CY2019	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	0	USD
CY2018	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	-600000	USD
CY2017	us-gaap	Other Comprehensive Income Availableforsale Securities Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent	500000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	7800000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	-13900000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax Parent OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTaxParent	700000	USD
CY2019	kalu	Other Comprehensive Income Loss Other OtherComprehensiveIncomeLossOther	0	USD
CY2018	kalu	Other Comprehensive Income Loss Other OtherComprehensiveIncomeLossOther	-100000	USD
CY2017	kalu	Other Comprehensive Income Loss Other OtherComprehensiveIncomeLossOther	200000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	10200000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-11700000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	0	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	72200000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	80000000.0	USD
CY2017	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	45400000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	45400000	USD
CY2017	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	200000	USD
CY2017	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	4500000	USD
CY2017Q1	us-gaap	Cumulative Effect Of New Accounting Principle In Period Of Adoption CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	300000	USD
CY2017	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	77800000	USD
CY2017	us-gaap	Treasury Stock Retired Cost Method Amount TreasuryStockRetiredCostMethodAmount	0	USD
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	35000000.0	USD
CY2017	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	13000000.0	USD
CY2018Q1	us-gaap	Cumulative Effect Of New Accounting Principle In Period Of Adoption CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	10300000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	91700000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-11700000	USD
CY2018	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	6900000	USD
CY2018	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	61900000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	37700000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	10100000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	740400000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	62000000.0	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	10200000	USD
CY2019	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	300000	USD
CY2019	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	6200000	USD
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	42900000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	39400000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	9500000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	733900000	USD
CY2019	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	96.18
CY2018	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	100.28
CY2017	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	82.97
CY2019Q4	us-gaap	Stock Repurchase Program Remaining Authorized Repurchase Amount1 StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1	105600000	USD
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.40
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.20
CY2017	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.00
CY2019	us-gaap	Net Income Loss NetIncomeLoss	62000000.0	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	91700000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	45400000	USD
CY2019	us-gaap	Depreciation Depreciation	46300000	USD
CY2018	us-gaap	Depreciation Depreciation	42100000	USD
CY2017	us-gaap	Depreciation Depreciation	38300000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2800000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1800000	USD
CY2017	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1400000	USD
CY2019	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	1200000	USD
CY2018	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	1000000.0	USD
CY2017	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	1200000	USD
CY2019	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	21100000	USD
CY2018	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	36700000	USD
CY2017	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	89000000.0	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	9800000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	10300000	USD
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	13300000	USD
CY2019	us-gaap	Asset Impairment Charges AssetImpairmentCharges	26100000	USD
CY2018	us-gaap	Asset Impairment Charges AssetImpairmentCharges	1400000	USD
CY2017	us-gaap	Asset Impairment Charges AssetImpairmentCharges	19200000	USD
CY2019	us-gaap	Gain Loss On Repurchase Of Debt Instrument GainLossOnRepurchaseOfDebtInstrument	-20300000	USD
CY2018	us-gaap	Gain Loss On Repurchase Of Debt Instrument GainLossOnRepurchaseOfDebtInstrument	0	USD
CY2017	us-gaap	Gain Loss On Repurchase Of Debt Instrument GainLossOnRepurchaseOfDebtInstrument	0	USD
CY2019	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	0	USD
CY2018	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	200000	USD
CY2017	us-gaap	Gain Loss On Sale Of Property Plant Equipment GainLossOnSaleOfPropertyPlantEquipment	500000	USD
CY2019	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	900000	USD
CY2018	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	2900000	USD
CY2017	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	2300000	USD
CY2019	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	7000000.0	USD
CY2018	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	6600000	USD
CY2017	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	4800000	USD
CY2019	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-8600000	USD
CY2018	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-21900000	USD
CY2017	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	15500000	USD
CY2019	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	-20200000	USD
CY2018	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	22300000	USD
CY2017	us-gaap	Increase Decrease In Accounts And Other Receivables IncreaseDecreaseInAccountsAndOtherReceivables	30900000	USD
CY2019	us-gaap	Increase Decrease In Contract With Customer Asset IncreaseDecreaseInContractWithCustomerAsset	-300000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	132200000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	135200000	USD
CY2018	us-gaap	Increase Decrease In Contract With Customer Asset IncreaseDecreaseInContractWithCustomerAsset	-700000	USD
CY2017	us-gaap	Increase Decrease In Contract With Customer Asset IncreaseDecreaseInContractWithCustomerAsset	0	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-37500000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	45000000.0	USD
CY2017	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	6300000	USD
CY2019	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	1700000	USD
CY2018	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	400000	USD
CY2017	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	1700000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	-24500000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	29200000	USD
CY2017	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	13000000.0	USD
CY2019	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	-7500000	USD
CY2018	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	-2600000	USD
CY2017	us-gaap	Increase Decrease In Other Accrued Liabilities IncreaseDecreaseInOtherAccruedLiabilities	-4700000	USD
CY2019	us-gaap	Other Postretirement Benefits Payments OtherPostretirementBenefitsPayments	2100000	USD
CY2018	us-gaap	Other Postretirement Benefits Payments OtherPostretirementBenefitsPayments	15700000	USD
CY2017	us-gaap	Other Postretirement Benefits Payments OtherPostretirementBenefitsPayments	20000000.0	USD
CY2019	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	-5800000	USD
CY2018	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	4100000	USD
CY2017	us-gaap	Increase Decrease In Other Noncurrent Assets And Liabilities Net IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	2200000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	232300000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	150200000	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	141500000	USD
CY2019	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	60200000	USD
CY2018	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	74100000	USD
CY2017	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	75500000	USD
CY2017	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	247500000	USD
CY2019	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	700000	USD
CY2018	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	900000	USD
CY2017	us-gaap	Payments To Acquire Available For Sale Securities Equity PaymentsToAcquireAvailableForSaleSecuritiesEquity	0	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	91100000	USD
CY2018	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	283900000	USD
CY2017	us-gaap	Proceeds From Sale And Maturity Of Available For Sale Securities ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities	296900000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
CY2018	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	43200000	USD
CY2017	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	200000	USD
CY2018	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	600000	USD
CY2017	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	600000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-101800000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	31100000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-25500000	USD
CY2019	us-gaap	Repayments Of Unsecured Debt RepaymentsOfUnsecuredDebt	391500000	USD
CY2018	us-gaap	Repayments Of Unsecured Debt RepaymentsOfUnsecuredDebt	0	USD
CY2017	us-gaap	Repayments Of Unsecured Debt RepaymentsOfUnsecuredDebt	0	USD
CY2019	us-gaap	Proceeds From Issuance Of Unsecured Debt ProceedsFromIssuanceOfUnsecuredDebt	500000000.0	USD
CY2018	us-gaap	Proceeds From Issuance Of Unsecured Debt ProceedsFromIssuanceOfUnsecuredDebt	0	USD
CY2017	us-gaap	Proceeds From Issuance Of Unsecured Debt ProceedsFromIssuanceOfUnsecuredDebt	0	USD
CY2019	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	8800000	USD
CY2018	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	0	USD
CY2017	us-gaap	Payments Of Financing Costs PaymentsOfFinancingCosts	0	USD
CY2019	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	1400000	USD
CY2018	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	700000	USD
CY2017	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	400000	USD
CY2019	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	6200000	USD
CY2018	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	6900000	USD
CY2017	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	4500000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	44200000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	60700000	USD
CY2017	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	79500000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	39400000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	37700000	USD
CY2017	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	35000000.0	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	8500000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-106000000.0	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-119400000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	139000000.0	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	75300000	USD
CY2017	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect	-3400000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	139600000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	64300000	USD
CY2016Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	67700000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	278600000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	139600000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	64300000	USD
CY2019	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	1	segment
CY2019	us-gaap	Use Of Estimates UseOfEstimates	<div style="line-height:120%;padding-top:12px;text-align:left;text-indent:18px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-style:italic;">Use of Estimates in the Preparation of Financial Statements.</span><span style="font-family:inherit;font-size:10pt;"> The preparation of financial statements in accordance with GAAP requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities known to exist as of the date the financial statements are published and the reported amounts of revenues and expenses during the reporting period. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of our consolidated financial statements; accordingly, it is possible that the actual results could differ from these estimates and assumptions, which could have a material effect on the reported amounts of our consolidated financial position and results of operations.</span></div>
CY2019	us-gaap	Effect Of Lifo Inventory Liquidation On Income EffectOfLIFOInventoryLiquidationOnIncome	3600000	USD
CY2019Q4	us-gaap	Inventory Lifo Reserve InventoryLIFOReserve	11900000	USD
CY2018Q4	us-gaap	Inventory Lifo Reserve InventoryLIFOReserve	31700000	USD
CY2019	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	1600000	USD
CY2018	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	1700000	USD
CY2017	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	2200000	USD
CY2019	us-gaap	Loss Contingency Undiscounted Amount Of Insurance Related Assessment Liability LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability	29200000	USD
CY2018	us-gaap	Loss Contingency Undiscounted Amount Of Insurance Related Assessment Liability LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability	27600000	USD
CY2019	us-gaap	Workers Compensation Discount Percent WorkersCompensationDiscountPercent	0.0175
CY2018	us-gaap	Workers Compensation Discount Percent WorkersCompensationDiscountPercent	0.0300
CY2019Q4	us-gaap	Accrued Employee Benefits Current And Noncurrent AccruedEmployeeBenefitsCurrentAndNoncurrent	3500000	USD
CY2018Q4	us-gaap	Accrued Employee Benefits Current And Noncurrent AccruedEmployeeBenefitsCurrentAndNoncurrent	3600000	USD
CY2019	us-gaap	Advertising Expense AdvertisingExpense	400000	USD
CY2018	us-gaap	Advertising Expense AdvertisingExpense	300000	USD
CY2017	us-gaap	Advertising Expense AdvertisingExpense	700000	USD
CY2019	us-gaap	Research And Development Expense ResearchAndDevelopmentExpense	10500000	USD
CY2018	us-gaap	Research And Development Expense ResearchAndDevelopmentExpense	9800000	USD
CY2017	us-gaap	Research And Development Expense ResearchAndDevelopmentExpense	10000000.0	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	125600000	USD
CY2019Q4	us-gaap	Billed Contract Receivables BilledContractReceivables	168500000	USD
CY2018Q4	us-gaap	Billed Contract Receivables BilledContractReceivables	179500000	USD
CY2019Q4	us-gaap	Unbilled Contracts Receivable UnbilledContractsReceivable	0	USD
CY2018Q4	us-gaap	Unbilled Contracts Receivable UnbilledContractsReceivable	1100000	USD
CY2019Q4	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	168500000	USD
CY2018Q4	us-gaap	Accounts Receivable Gross Current AccountsReceivableGrossCurrent	180600000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	1400000	USD
CY2019Q4	us-gaap	Cash Cash	28200000	USD
CY2018Q4	us-gaap	Cash Cash	22900000	USD
CY2019Q4	us-gaap	Commercial Paper At Carrying Value CommercialPaperAtCarryingValue	236100000	USD
CY2018Q4	us-gaap	Commercial Paper At Carrying Value CommercialPaperAtCarryingValue	102700000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	264300000	USD
CY2018Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	800000	USD
CY2019Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	167100000	USD
CY2018Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	179800000	USD
CY2019Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	42600000	USD
CY2018Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	48000000.0	USD
CY2019Q4	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	63500000	USD
CY2018Q4	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	85600000	USD
CY2019Q4	us-gaap	Inventory Raw Materials Net Of Reserves InventoryRawMaterialsNetOfReserves	65000000.0	USD
CY2018Q4	us-gaap	Inventory Raw Materials Net Of Reserves InventoryRawMaterialsNetOfReserves	75000000.0	USD
CY2019Q4	us-gaap	Inventory Supplies Net Of Reserves InventorySuppliesNetOfReserves	6500000	USD
CY2018Q4	us-gaap	Inventory Supplies Net Of Reserves InventorySuppliesNetOfReserves	6500000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	177600000	USD
CY2018Q4	us-gaap	Inventory Net InventoryNet	215100000	USD
CY2019Q4	us-gaap	Land Land	21400000	USD
CY2018Q4	us-gaap	Land Land	21400000	USD
CY2019Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	104500000	USD
CY2018Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	97000000.0	USD
CY2019Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	813500000	USD
CY2018Q4	us-gaap	Machinery And Equipment Gross MachineryAndEquipmentGross	755600000	USD
CY2019Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	33200000	USD
CY2018Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	43600000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	972600000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	917600000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	352200000	USD
CY2018Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	307400000	USD
CY2019Q4	us-gaap	Assets Held For Sale Not Part Of Disposal Group AssetsHeldForSaleNotPartOfDisposalGroup	1600000	USD
CY2018Q4	us-gaap	Assets Held For Sale Not Part Of Disposal Group AssetsHeldForSaleNotPartOfDisposalGroup	1600000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	622000000.0	USD
CY2018Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	611800000	USD
CY2019Q4	us-gaap	Bank Overdrafts BankOverdrafts	4200000	USD
CY2018Q4	us-gaap	Bank Overdrafts BankOverdrafts	4800000	USD
CY2019Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	6200000	USD
CY2018Q4	us-gaap	Taxes Payable Current TaxesPayableCurrent	6500000	USD
CY2019Q4	kalu	Accrued Annual Veba Contribution AccruedAnnualVebaContribution	2900000	USD
CY2018Q4	kalu	Accrued Annual Veba Contribution AccruedAnnualVebaContribution	2100000	USD
CY2019Q4	us-gaap	Interest Payable Current InterestPayableCurrent	2300000	USD
CY2018Q4	us-gaap	Interest Payable Current InterestPayableCurrent	2900000	USD
CY2019Q4	us-gaap	Accrued Environmental Loss Contingencies Current AccruedEnvironmentalLossContingenciesCurrent	5500000	USD
CY2018Q4	us-gaap	Accrued Environmental Loss Contingencies Current AccruedEnvironmentalLossContingenciesCurrent	2600000	USD
CY2019Q4	us-gaap	Accrued Liabilities And Other Liabilities AccruedLiabilitiesAndOtherLiabilities	22900000	USD
CY2018Q4	us-gaap	Accrued Liabilities And Other Liabilities AccruedLiabilitiesAndOtherLiabilities	25100000	USD
CY2019Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	44000000.0	USD
CY2018Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	44000000.0	USD
CY2019Q4	us-gaap	Self Insurance Reserve Noncurrent SelfInsuranceReserveNoncurrent	27700000	USD
CY2018Q4	us-gaap	Self Insurance Reserve Noncurrent SelfInsuranceReserveNoncurrent	24600000	USD
CY2019Q4	us-gaap	Accrued Environmental Loss Contingencies Noncurrent AccruedEnvironmentalLossContingenciesNoncurrent	11500000	USD
CY2018Q4	us-gaap	Accrued Environmental Loss Contingencies Noncurrent AccruedEnvironmentalLossContingenciesNoncurrent	14300000	USD
CY2019Q4	us-gaap	Other Sundry Liabilities Noncurrent OtherSundryLiabilitiesNoncurrent	27800000	USD
CY2018Q4	us-gaap	Other Sundry Liabilities Noncurrent OtherSundryLiabilitiesNoncurrent	27500000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	67000000.0	USD
CY2018Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	66400000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P20Y
CY2019	kalu	Lessee Operating Lease Optionto Terminate Duration LesseeOperatingLeaseOptiontoTerminateDuration	P1Y
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P5Y9M18D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P10Y4M24D
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.045
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.058
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	25800000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	6600000	USD
CY2019Q4	kalu	Rightof Use Asset Total RightofUseAssetTotal	32400000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	3900000	USD
CY2019Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	1200000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	25200000	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	5400000	USD
CY2019Q4	kalu	Lease Liability Total LeaseLiabilityTotal	35700000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	7500000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	1200000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	1500000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	300000	USD
CY2019	us-gaap	Lease Cost LeaseCost	10500000	USD
CY2018	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	8200000	USD
CY2017	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	7900000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	2800000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	1600000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	5400000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	1400000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	4600000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	1300000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	3800000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	1200000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	3500000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	700000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	3300000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	1300000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	18700000	USD
CY2019Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	7500000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	39300000	USD
CY2019Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	900000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	10200000	USD
CY2019Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	6600000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	29100000	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Due Current CapitalLeasesFutureMinimumPaymentsDueCurrent	1700000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	6100000	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Due In Two Years CapitalLeasesFutureMinimumPaymentsDueInTwoYears	1400000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	3700000	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Due In Three Years CapitalLeasesFutureMinimumPaymentsDueInThreeYears	1200000	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Due In Four Years CapitalLeasesFutureMinimumPaymentsDueInFourYears	1100000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	2400000	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Due In Five Years CapitalLeasesFutureMinimumPaymentsDueInFiveYears	1000000.0	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	2200000	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Due Thereafter CapitalLeasesFutureMinimumPaymentsDueThereafter	1800000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	20800000	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Due CapitalLeasesFutureMinimumPaymentsDue	8200000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	38000000.0	USD
CY2018Q4	us-gaap	Capital Leases Future Minimum Payments Interest Included In Payments CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments	1200000	USD
CY2018Q4	us-gaap	Capital Lease Obligations CapitalLeaseObligations	7000000.0	USD
CY2018Q4	us-gaap	Capital Lease Obligations CapitalLeaseObligations	7000000.0	USD
CY2018Q4	us-gaap	Capital Leased Assets Gross CapitalLeasedAssetsGross	8300000	USD
CY2018Q4	us-gaap	Capital Leases Lessee Balance Sheet Assets By Major Class Accumulated Deprecation CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation	1300000	USD
CY2018	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	25200000	USD
CY2018	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	25200000	USD
CY2018Q2	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	18400000	USD
CY2018Q4	us-gaap	Goodwill Gross GoodwillGross	62400000	USD
CY2019	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	0	USD
CY2019Q4	us-gaap	Goodwill Gross GoodwillGross	62400000	USD
CY2018Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	18400000	USD
CY2019	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	25200000	USD
CY2019Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	43600000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	44000000.0	USD
CY2019	us-gaap	Goodwill Period Increase Decrease GoodwillPeriodIncreaseDecrease	-25200000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	18800000	USD
CY2017Q4	us-gaap	Goodwill Gross GoodwillGross	37200000	USD
CY2018	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	25200000	USD
CY2018Q4	us-gaap	Goodwill Gross GoodwillGross	62400000	USD
CY2017Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	18400000	USD
CY2018	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2018Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss	18400000	USD
CY2017Q4	us-gaap	Goodwill Goodwill	18800000	USD
CY2018	us-gaap	Goodwill Period Increase Decrease GoodwillPeriodIncreaseDecrease	25200000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	44000000.0	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	43900000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	14300000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	29600000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	43900000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	11500000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	32400000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2800000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1800000	USD
CY2017	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1400000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	2800000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	2800000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	2800000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	2600000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	1800000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	16800000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	29600000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Next Twelve Months DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	8200000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	7900000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Three DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	7700000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	7400000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	7100000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	31100000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	70600000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	68100000	USD
CY2019	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	8800000	USD
CY2018	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	8800000	USD
CY2017	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	8900000	USD
CY2019	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	1600000	USD
CY2018	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	1000000.0	USD
CY2017	us-gaap	Deferred Compensation Arrangement With Individual Compensation Expense DeferredCompensationArrangementWithIndividualCompensationExpense	1800000	USD
CY2019	us-gaap	Multiemployer Plan Contributions By Employer MultiemployerPlanContributionsByEmployer	5000000.0	USD
CY2018	us-gaap	Multiemployer Plan Contributions By Employer MultiemployerPlanContributionsByEmployer	4700000	USD
CY2017	us-gaap	Multiemployer Plan Contributions By Employer MultiemployerPlanContributionsByEmployer	4600000	USD
CY2019Q4	kalu	Multiemployer Plans Collective Bargaining Arrangement Percentage Of Employers Participants To All Employees MultiemployerPlansCollectiveBargainingArrangementPercentageOfEmployersParticipantsToAllEmployees	0.51
CY2019	us-gaap	Multiemployer Plan Contributions By Employer MultiemployerPlanContributionsByEmployer	5000000.0	USD
CY2018	us-gaap	Multiemployer Plan Contributions By Employer MultiemployerPlanContributionsByEmployer	4700000	USD
CY2017	us-gaap	Multiemployer Plan Contributions By Employer MultiemployerPlanContributionsByEmployer	4600000	USD
CY2019	us-gaap	Multiemployer Plan Collective Bargaining Arrangement Required Percentage Of Contributions MultiemployerPlanCollectiveBargainingArrangementRequiredPercentageOfContributions	0.05
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	486023	shares
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	80.99
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	95.28
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P2Y9M18D
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10100000	USD
CY2017	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	13100000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	2400000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	2500000	USD
CY2017	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	4900000	USD
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	16400000	USD
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	19400000	USD
CY2017	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	12000000.0	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	9700000	USD
CY2019Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	7200000	USD
CY2018Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	12600000	USD
CY2019Q4	us-gaap	Margin Deposit Assets MarginDepositAssets	0	USD
CY2019Q4	us-gaap	Customer Deposits Current CustomerDepositsCurrent	200000	USD
CY2019	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	1215200000	USD
CY2018	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	1300700000	USD
CY2017	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	1085900000	USD
CY2019	us-gaap	Debt Instrument Term DebtInstrumentTerm	P12M
CY2018Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	6300000	USD
CY2017Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	5900000	USD
CY2016Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	5500000	USD
CY2019	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	200000	USD
CY2018	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	0	USD
CY2017	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	0	USD
CY2019	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	500000	USD
CY2018	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	400000	USD
CY2017	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	400000	USD
CY2019	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-100000	USD
CY2018	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	0	USD
CY2017	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	0	USD
CY2019Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	6500000	USD
CY2018Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	6300000	USD
CY2017Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	5900000	USD
CY2019	kalu	Period For Final Feasibility Study PeriodForFinalFeasibilityStudy	P12M
CY2018	us-gaap	Investment Income Interest InvestmentIncomeInterest	300000	USD
CY2017	us-gaap	Investment Income Interest InvestmentIncomeInterest	200000	USD
CY2018Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	16900000	USD
CY2017Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	16600000	USD
CY2016Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	17200000	USD
CY2019	us-gaap	Accrual For Environmental Loss Contingencies Increase Decrease For Revision In Estimates AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates	1800000	USD
CY2018	us-gaap	Accrual For Environmental Loss Contingencies Increase Decrease For Revision In Estimates AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates	1700000	USD
CY2017	us-gaap	Accrual For Environmental Loss Contingencies Increase Decrease For Revision In Estimates AccrualForEnvironmentalLossContingenciesIncreaseDecreaseForRevisionInEstimates	300000	USD
CY2019	us-gaap	Accrual For Environmental Loss Contingencies Payments1 AccrualForEnvironmentalLossContingenciesPayments1	1700000	USD
CY2018	us-gaap	Accrual For Environmental Loss Contingencies Payments1 AccrualForEnvironmentalLossContingenciesPayments1	1400000	USD
CY2017	us-gaap	Accrual For Environmental Loss Contingencies Payments1 AccrualForEnvironmentalLossContingenciesPayments1	900000	USD
CY2019Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	17000000.0	USD
CY2018Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	16900000	USD
CY2017Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	16600000	USD
CY2019Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	17000000.0	USD
CY2019	kalu	Expected Period Related To Remediation Expenditures For Environmental Contingencies ExpectedPeriodRelatedToRemediationExpendituresForEnvironmentalContingencies	P30Y
CY2019Q4	us-gaap	Loss Contingency Range Of Possible Loss Portion Not Accrued LossContingencyRangeOfPossibleLossPortionNotAccrued	11600000	USD
CY2019	kalu	Time Period Within Which Companys Recorded Estimate Of Its Obligation May Change TimePeriodWithinWhichCompanysRecordedEstimateOfItsObligationMayChange	P12M
CY2019	us-gaap	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths	-5500000	USD
CY2019	us-gaap	Investment Income Interest InvestmentIncomeInterest	600000	USD
CY2019	kalu	Defined Benefit Plan Net Periodic Cost Benefit Veb As DefinedBenefitPlanNetPeriodicCostBenefitVEBAs	6500000	USD
CY2018	kalu	Defined Benefit Plan Net Periodic Cost Benefit Veb As DefinedBenefitPlanNetPeriodicCostBenefitVEBAs	6000000.0	USD
CY2017	kalu	Defined Benefit Plan Net Periodic Cost Benefit Veb As DefinedBenefitPlanNetPeriodicCostBenefitVEBAs	4500000	USD
CY2019	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	4400000	USD
CY2018	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	5400000	USD
CY2017	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	3200000	USD
CY2019	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	700000	USD
CY2018	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	-1000000.0	USD
CY2017	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	0	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-20300000	USD
CY2018	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2017	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	0	USD
CY2019	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	400000	USD
CY2018	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	400000	USD
CY2017	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	1100000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-20700000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	-900000	USD
CY2017	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	0	USD
CY2017	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	300000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	76300000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	114600000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	127900000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	4100000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	5400000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	5100000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	80400000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	120000000.0	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	133000000.0	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-5700000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1100000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1800000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-2800000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	19600000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	300000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	4500000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	24400000	USD
CY2019	kalu	Federal Income Tax Provision Benefit Other FederalIncomeTaxProvisionBenefitOther	-2700000	USD
CY2019	kalu	Foreign Income Tax Provision Benefit Other ForeignIncomeTaxProvisionBenefitOther	100000	USD
CY2019	kalu	State Income Tax Provision Benefit Other StateIncomeTaxProvisionBenefitOther	-600000	USD
CY2019	us-gaap	Other Income Tax Expense Benefit Continuing Operations OtherIncomeTaxExpenseBenefitContinuingOperations	-3200000	USD
CY2019	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	11200000	USD
CY2019	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	1500000	USD
CY2019	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	5700000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18400000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-11900000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	1900000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1500000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-8500000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	34700000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-100000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	1400000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	36000000.0	USD
CY2018	kalu	Federal Income Tax Provision Benefit Other FederalIncomeTaxProvisionBenefitOther	700000	USD
CY2018	kalu	Foreign Income Tax Provision Benefit Other ForeignIncomeTaxProvisionBenefitOther	0	USD
CY2018	kalu	State Income Tax Provision Benefit Other StateIncomeTaxProvisionBenefitOther	100000	USD
CY2018	us-gaap	Other Income Tax Expense Benefit Continuing Operations OtherIncomeTaxExpenseBenefitContinuingOperations	800000	USD
CY2018	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	23500000	USD
CY2018	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	1800000	USD
CY2018	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	3000000.0	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	28300000	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-3100000	USD
CY2017	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	800000	USD
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1000000.0	USD
CY2017	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-1300000	USD
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	82000000.0	USD
CY2017	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	1000000.0	USD
CY2017	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	5700000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	88700000	USD
CY2017	kalu	Federal Income Tax Provision Benefit Other FederalIncomeTaxProvisionBenefitOther	100000	USD
CY2017	kalu	Foreign Income Tax Provision Benefit Other ForeignIncomeTaxProvisionBenefitOther	100000	USD
CY2017	kalu	State Income Tax Provision Benefit Other StateIncomeTaxProvisionBenefitOther	0	USD
CY2017	us-gaap	Other Income Tax Expense Benefit Continuing Operations OtherIncomeTaxExpenseBenefitContinuingOperations	200000	USD
CY2017	us-gaap	Federal Income Tax Expense Benefit Continuing Operations FederalIncomeTaxExpenseBenefitContinuingOperations	79000000.0	USD
CY2017	us-gaap	Foreign Income Tax Expense Benefit Continuing Operations ForeignIncomeTaxExpenseBenefitContinuingOperations	1900000	USD
CY2017	us-gaap	State And Local Income Tax Expense Benefit Continuing Operations StateAndLocalIncomeTaxExpenseBenefitContinuingOperations	6700000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	87600000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	16900000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	25200000	USD
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	46500000	USD
CY2019	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	100000	USD
CY2018	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-1700000	USD
CY2017	us-gaap	Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance	-500000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	1700000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	600000	USD
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost	2300000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	-100000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	1500000	USD
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense Other IncomeTaxReconciliationNondeductibleExpenseOther	0	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4500000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	2500000	USD
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4300000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	7700000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	0	USD
CY2017	us-gaap	Income Tax Reconciliation Tax Credits Research IncomeTaxReconciliationTaxCreditsResearch	0	USD
CY2019	kalu	Effective Income Tax Rate Reconciliation Tax Contingency Current Year Taxpositions Amount EffectiveIncomeTaxRateReconciliationTaxContingencyCurrentYearTaxpositionsAmount	300000	USD
CY2018	kalu	Effective Income Tax Rate Reconciliation Tax Contingency Current Year Taxpositions Amount EffectiveIncomeTaxRateReconciliationTaxContingencyCurrentYearTaxpositionsAmount	0	USD
CY2017	kalu	Effective Income Tax Rate Reconciliation Tax Contingency Current Year Taxpositions Amount EffectiveIncomeTaxRateReconciliationTaxContingencyCurrentYearTaxpositionsAmount	0	USD
CY2019	kalu	Effective Income Tax Rate Reconciliation Tax Contingency Prior Year Taxpositions Amount EffectiveIncomeTaxRateReconciliationTaxContingencyPriorYearTaxpositionsAmount	2400000	USD
CY2018	kalu	Effective Income Tax Rate Reconciliation Tax Contingency Prior Year Taxpositions Amount EffectiveIncomeTaxRateReconciliationTaxContingencyPriorYearTaxpositionsAmount	0	USD
CY2017	kalu	Effective Income Tax Rate Reconciliation Tax Contingency Prior Year Taxpositions Amount EffectiveIncomeTaxRateReconciliationTaxContingencyPriorYearTaxpositionsAmount	0	USD
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	100000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	500000	USD
CY2017	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	100000	USD
CY2019	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	200000	USD
CY2018	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	-400000	USD
CY2017	us-gaap	Income Tax Reconciliation Repatriation Of Foreign Earnings IncomeTaxReconciliationRepatriationOfForeignEarnings	5900000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Settlements Foreign IncomeTaxReconciliationTaxSettlementsForeign	0	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Settlements Foreign IncomeTaxReconciliationTaxSettlementsForeign	100000	USD
CY2017	us-gaap	Income Tax Reconciliation Tax Settlements Foreign IncomeTaxReconciliationTaxSettlementsForeign	29000000.0	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18400000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	28300000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	87600000	USD
CY2017	us-gaap	Income Tax Reconciliation Change In Enacted Tax Rate IncomeTaxReconciliationChangeInEnactedTaxRate	-2500000	USD
CY2019Q4	kalu	Deferred Tax Assets Operating Loss Carryforwards And Tax Credits DeferredTaxAssetsOperatingLossCarryforwardsAndTaxCredits	48700000	USD
CY2018Q4	kalu	Deferred Tax Assets Operating Loss Carryforwards And Tax Credits DeferredTaxAssetsOperatingLossCarryforwardsAndTaxCredits	48700000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Pensions DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions	8700000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Pensions DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions	8000000.0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	30100000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	27200000	USD
CY2019Q4	kalu	Deferred Tax Assets Leased Assets DeferredTaxAssetsLeasedAssets	7100000	USD
CY2018Q4	kalu	Deferred Tax Assets Leased Assets DeferredTaxAssetsLeasedAssets	0	USD
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Inventory DeferredTaxAssetsInventory	9400000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Inventory DeferredTaxAssetsInventory	20000000.0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	9900000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	8400000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	94100000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	95500000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	78500000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	62000000.0	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	6300000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Leasing Arrangements DeferredTaxLiabilitiesLeasingArrangements	0	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Capitalized Inventory Costs DeferredTaxLiabilitiesDeferredExpenseCapitalizedInventoryCosts	2000000.0	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Deferred Expense Capitalized Inventory Costs DeferredTaxLiabilitiesDeferredExpenseCapitalizedInventoryCosts	1800000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	86800000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	63800000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	7300000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	31700000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	7300000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net Noncurrent DeferredTaxAssetsLiabilitiesNetNoncurrent	11800000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	4500000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	31700000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Liabilities Net Noncurrent DeferredTaxAssetsLiabilitiesNetNoncurrent	35900000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	4200000	USD
CY2019Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	121300000	USD
CY2019Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	5700000	USD
CY2019	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	1500000	USD
CY2018	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	-4600000	USD
CY2017	us-gaap	Valuation Allowance Deferred Tax Asset Change In Amount ValuationAllowanceDeferredTaxAssetChangeInAmount	-2700000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1500000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1500000	USD
CY2016Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1800000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	300000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	2300000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	17259000	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16874000	shares
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.88
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.53
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.67
CY2019	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2018	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	300000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	4100000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1500000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	1500000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	4100000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	900000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	300000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	200000	USD
CY2019Q4	kalu	Accrued Interest And Penalty On Unrecognized Tax Benefits Current AccruedInterestAndPenaltyOnUnrecognizedTaxBenefitsCurrent	0	USD
CY2019Q4	us-gaap	Income Tax Examination Increase Decrease In Liability From Prior Year IncomeTaxExaminationIncreaseDecreaseInLiabilityFromPriorYear	-100000	USD
CY2018Q4	us-gaap	Income Tax Examination Increase Decrease In Liability From Prior Year IncomeTaxExaminationIncreaseDecreaseInLiabilityFromPriorYear	-100000	USD
CY2017Q4	us-gaap	Income Tax Examination Increase Decrease In Liability From Prior Year IncomeTaxExaminationIncreaseDecreaseInLiabilityFromPriorYear	-100000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	62000000.0	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	91700000	USD
CY2017	us-gaap	Net Income Loss NetIncomeLoss	45400000	USD
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15997000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16585000	shares
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	16996000	shares
CY2019	us-gaap	Incremental Common Shares Attributable To Nonvested Shares With Forfeitable Dividends IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends	206000	shares
CY2018	us-gaap	Incremental Common Shares Attributable To Nonvested Shares With Forfeitable Dividends IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends	289000	shares
CY2017	us-gaap	Incremental Common Shares Attributable To Nonvested Shares With Forfeitable Dividends IncrementalCommonSharesAttributableToNonvestedSharesWithForfeitableDividends	263000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	16203000	shares
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.83
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.43
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.63
CY2017	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	52000	shares
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	23600000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	21600000	USD
CY2017	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	21100000	USD
CY2019	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	4500000	USD
CY2018	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	7000000.0	USD
CY2017	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	7400000	USD
CY2019	us-gaap	Other Significant Noncash Transaction Value Of Consideration Given1 OtherSignificantNoncashTransactionValueOfConsiderationGiven1	0	USD
CY2018	us-gaap	Other Significant Noncash Transaction Value Of Consideration Given1 OtherSignificantNoncashTransactionValueOfConsiderationGiven1	1300000	USD
CY2017	us-gaap	Other Significant Noncash Transaction Value Of Consideration Given1 OtherSignificantNoncashTransactionValueOfConsiderationGiven1	100000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1800000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	3800000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	1000000.0	USD
CY2018	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	6500000	USD
CY2017	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	1200000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	264300000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	125600000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	51100000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	300000	USD
CY2018Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	300000	USD
CY2017Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	300000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	14000000.0	USD
CY2018Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	13700000	USD
CY2017Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	12900000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	278600000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	139600000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	64300000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1514100000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1585900000	USD
CY2017	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1397500000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1514100000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1585900000	USD
CY2019	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1514100000	USD
CY2018	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1585900000	USD
CY2017	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	1397500000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	5500000	USD
CY2018	us-gaap	Income Taxes Paid IncomeTaxesPaid	3600000	USD
CY2017	us-gaap	Income Taxes Paid IncomeTaxesPaid	1300000	USD
CY2019Q4	us-gaap	Noncurrent Assets NoncurrentAssets	622000000.0	USD
CY2018Q4	us-gaap	Noncurrent Assets NoncurrentAssets	611800000	USD
CY2017Q4	us-gaap	Noncurrent Assets NoncurrentAssets	571400000	USD
CY2019Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	395200000	USD
CY2019Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	375300000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	374900000	USD
CY2019Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	368700000	USD
CY2019Q1	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	315100000	USD
CY2019Q2	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	303500000	USD
CY2019Q3	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	298600000	USD
CY2019Q4	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	298000000.0	USD
CY2019Q1	us-gaap	Gross Profit GrossProfit	80100000	USD
CY2019Q2	us-gaap	Gross Profit GrossProfit	71800000	USD
CY2019Q3	us-gaap	Gross Profit GrossProfit	76300000	USD
CY2019Q4	us-gaap	Gross Profit GrossProfit	70700000	USD
CY2019Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	43000000.0	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	32400000	USD
CY2019Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	40700000	USD
CY2019Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	9600000	USD
CY2019Q1	us-gaap	Net Income Loss NetIncomeLoss	28000000.0	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	19200000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	25400000	USD
CY2019Q4	us-gaap	Net Income Loss NetIncomeLoss	-10600000	USD
CY2019Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.74
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.59
CY2018Q2	us-gaap	Gross Profit GrossProfit	72000000.0	USD
CY2018Q3	us-gaap	Gross Profit GrossProfit	69800000	USD
CY2018Q4	us-gaap	Gross Profit GrossProfit	72100000	USD
CY2018Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	37100000	USD
CY2018Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	34700000	USD
CY2018Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	34900000	USD
CY2018Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	36900000	USD
CY2018Q1	us-gaap	Net Income Loss NetIncomeLoss	25700000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	20700000	USD
CY2018Q3	us-gaap	Net Income Loss NetIncomeLoss	21700000	USD
CY2019Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.66
CY2019Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.71
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.18
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.57
CY2019Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.66
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2019Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.60
CY2019Q4	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	25200000	USD
CY2019	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-20300000	USD
CY2018Q1	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	388000000.0	USD
CY2018Q2	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	415400000	USD
CY2018Q3	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	393100000	USD
CY2018Q4	us-gaap	Revenue From Contract With Customer Excluding Assessed Tax RevenueFromContractWithCustomerExcludingAssessedTax	389400000	USD
CY2018Q1	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	316700000	USD
CY2018Q2	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	343400000	USD
CY2018Q3	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	323300000	USD
CY2018Q4	us-gaap	Cost Of Goods And Service Excluding Depreciation Depletion And Amortization CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization	317300000	USD
CY2018Q1	us-gaap	Gross Profit GrossProfit	71300000	USD
CY2018Q4	us-gaap	Net Income Loss NetIncomeLoss	23600000	USD
CY2018Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.54
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.24
CY2018Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.31
CY2018Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.44
CY2018Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.51
CY2018Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.22
CY2018Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.29
CY2018Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.41
CY2018Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.55
CY2018Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.55
CY2018Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.55
CY2018Q4	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.55

Files In Submission

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$KALU
KAISER ALUMINUM CORP Stock $kalu

2019 Q4 Form 10-K Financial Statement

#000081159620000010 Filed on February 25, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$KALU KAISER ALUMINUM CORP Stock $kalu

2019 Q4 Form 10-K Financial Statement

#000081159620000010 Filed on February 25, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$KALU
KAISER ALUMINUM CORP Stock $kalu