75000 - Document - Document and Entity Information
link:presentationLink
link:calculationLink
link:definitionLink
75010 - Statement - Statement of Consolidated Operations (unaudited)
link:presentationLink
link:calculationLink
link:definitionLink
75020 - Statement - Statement of Consolidated Comprehensive Income (unaudited)
link:presentationLink
link:calculationLink
link:definitionLink
75030 - Statement - Consolidated Balance Sheet (unaudited)
link:presentationLink
link:calculationLink
link:definitionLink
75040 - Statement - Statement of Consolidated Cash Flows (unaudited)
link:presentationLink
link:calculationLink
link:definitionLink
75050 - Statement - Statement of Changes in Consolidated Mezzanine Equity and Equity (unaudited)
link:presentationLink
link:calculationLink
link:definitionLink
75060 - Statement - Statement of Changes in Consolidated Mezzanine Equity and Equity (unaudited) (Parenthetical)
link:presentationLink
link:calculationLink
link:definitionLink
995455 - Disclosure - Basis of Presentation
link:presentationLink
link:calculationLink
link:definitionLink
995465 - Disclosure - Recently Adopted and Recently Issued Accounting Guidance
link:presentationLink
link:calculationLink
link:definitionLink
995475 - Disclosure - Acquisitions, Divestitures, and Joint Ventures
link:presentationLink
link:calculationLink
link:definitionLink
995485 - Disclosure - Restructuring and Other Charges, Net
link:presentationLink
link:calculationLink
link:definitionLink
995495 - Disclosure - Segment Information
link:presentationLink
link:calculationLink
link:definitionLink
995505 - Disclosure - Earnings Per Share
link:presentationLink
link:calculationLink
link:definitionLink
995515 - Disclosure - Accumulated Other Comprehensive Loss
link:presentationLink
link:calculationLink
link:definitionLink
995525 - Disclosure - Receivables
link:presentationLink
link:calculationLink
link:definitionLink
995535 - Disclosure - Inventories
link:presentationLink
link:calculationLink
link:definitionLink
995545 - Disclosure - Debt
link:presentationLink
link:calculationLink
link:definitionLink
995555 - Disclosure - Pension and Other Postretirement Benefits
link:presentationLink
link:calculationLink
link:definitionLink
995565 - Disclosure - Derivatives and Other Financial Instruments
link:presentationLink
link:calculationLink
link:definitionLink
995575 - Disclosure - Income Taxes
link:presentationLink
link:calculationLink
link:definitionLink
995585 - Disclosure - Contingencies
link:presentationLink
link:calculationLink
link:definitionLink
995595 - Disclosure - Other Financial Information
link:presentationLink
link:calculationLink
link:definitionLink
995605 - Disclosure - Subsequent Events
link:presentationLink
link:calculationLink
link:definitionLink
995615 - Disclosure - Basis of Presentation (Policies)
link:presentationLink
link:calculationLink
link:definitionLink
995625 - Disclosure - Restructuring and Other Charges, Net (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995635 - Disclosure - Segment Information (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995645 - Disclosure - Earnings Per Share (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995655 - Disclosure - Accumulated Other Comprehensive Loss (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995665 - Disclosure - Inventories (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995675 - Disclosure - Pension and Other Postretirement Benefits (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995685 - Disclosure - Derivatives and Other Financial Instruments (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995695 - Disclosure - Income Taxes (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995705 - Disclosure - Contingencies (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995715 - Disclosure - Other Financial Information (Tables)
link:presentationLink
link:calculationLink
link:definitionLink
995725 - Disclosure - Acquisitions, Divestitures, and Joint Ventures - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995735 - Disclosure - Restructuring and Other Charges, Net - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995745 - Disclosure - Restructuring and Other Charges, Net - Schedule of Restructuring and Other Charges, Net by Reportable Segments, Pretax (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995755 - Disclosure - Restructuring and Other Charges, Net - Activity and Reserve Balances for Restructuring and Other Charges (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995765 - Disclosure - Segment Information - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995775 - Disclosure - Segment Information - Schedule of Operating Results, Capital Expenditures and Assets of Alcoa's Reportable Segments (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995785 - Disclosure - Segment Information - Schedule of Segment Adjusted EBITDA to Consolidated Net Income (Loss) Attributable to Alcoa Corporation (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995795 - Disclosure - Segment Information - Schedule of Third-party Sales by Product Division (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995805 - Disclosure - Earnings Per Share - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995815 - Disclosure - Earnings Per Share - Schedule of Computation of Basic and Diluted EPS Attributable to Alcoa Corporation Common Shareholders (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995825 - Disclosure - Accumulated Other Comprehensive Loss - Summary of Changes in Accumulated Other Comprehensive Loss by Component (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995835 - Disclosure - Receivables - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995845 - Disclosure - Inventories - Schedule of Inventory Components (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995855 - Disclosure - Debt - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995865 - Disclosure - Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995875 - Disclosure - Pension and Other Postretirement Benefits - Summary of Information in Curtailment or Settlement of Benefits Requiring Remeasurement, Update to Discount Rates Used to Determine Benefit Obligations of Affected Plans (Details)
link:presentationLink
link:calculationLink
link:definitionLink
995885 - Disclosure - Pension and Other Postretirement Benefits - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995895 - Disclosure - Derivatives and Other Financial Instruments - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995905 - Disclosure - Derivatives and Other Financial Instruments - Schedule of Detail for Level 1, 2 and 3 Derivatives (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995915 - Disclosure - Derivatives and Other Financial Instruments - Schedule of Outstanding Quantities of Derivative Instruments (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995925 - Disclosure - Derivatives and Other Financial Instruments - Schedule of Quantitative Information for Level 3 Derivative Contracts (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995935 - Disclosure - Derivatives and Other Financial Instruments - Schedule of Fair Values of Level 3 Derivative Instruments Recorded as Assets and Liabilities (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995945 - Disclosure - Derivatives and Other Financial Instruments - Schedule of Reconciliation of Activity for Derivative Contracts (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995955 - Disclosure - Derivatives and Other Financial Instruments - Schedule of Carrying Values and Fair Values of Other Financial Instruments (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995965 - Disclosure - Income Taxes - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995975 - Disclosure - Income Taxes - Schedule of Income Taxes (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995985 - Disclosure - Contingencies - Changes in Carrying Value of Recorded Environmental Remediation Reserves (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
995995 - Disclosure - Contingencies - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
996005 - Disclosure - Contingencies - Additional Information - 1 (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
996015 - Disclosure - Contingencies - Estimate Timing of Cash Outflows from Environmental Reserves (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
996025 - Disclosure - Other Financial Information - Schedule of Other Expenses (Income), Net (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
996035 - Disclosure - Other Financial Information - Schedule of Other Noncurrent Assets (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
996045 - Disclosure - Other Financial Information - Schedule of Cash and Cash Equivalents and Restricted Cash (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
996055 - Disclosure - Other Financial Information - Additional Information (Detail)
link:presentationLink
link:calculationLink
link:definitionLink
Minimum required cash contribution to pension plans
Minimum Required Cash Contribution To Pension Plan
Minimum required cash contribution to pension plan.
IRA Section Forty Five X Credit Non Current
IRA Section 45X credit.
IRA Section 45X credit
Business Combination, Acquisition-Related Cost, Expense
Transaction-related costs
Proceeds from the sale of assets
Proceeds from Sale of Property, Plant, and Equipment
Proceeds from Sale of Property, Plant, and Equipment, Total
Schedule of Reconciliation of Activity for Derivative Contracts
Fair Value Assets Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Text Block]
Tabular disclosure of the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and gains or losses recognized in other comprehensive income (loss) and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs) by class of asset and liability.
Retirement Plan Type
Retirement Plan Type [Axis]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax
Total Other comprehensive income (loss) before reclassifications, net of tax
Segments
Segments [Domain]
Dividends, Preferred Stock
Dividends, Preferred Stock, Total
Preferred stock dividends paid
Dividends paid on Alcoa preferred stock ($0.10 per share)
Proceeds from Short-Term Debt
Proceeds from Short-Term Debt, Total
Proceeds from bridge financing
Thereafter
Accrual for Environmental Loss Contingency, Undiscounted, to be Paid, after Year Five
Restructuring Reserve, Total
Restructuring reserve beginning balance
Restructuring reserve ending balance
Restructuring Reserve
Receivables
Financing Receivables [Text Block]
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Preferred stock issued
Preferred Stock, Shares Issued
Balance Sheet Location
Statement of Financial Position Location, Balance [Domain]
Derivative Assets Noncurrent
Total asset derivatives
Fair value of derivative instruments (L)
Fair value measurement, Liabilities, Ending balance
Fair value measurement, Liabilities, Beginning balance
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]
Schedule of Detail for Level 1, 2 and 3 Derivatives
Debt Instruments Maturity Year
Debt instruments maturity year.
Debt instrument maturity date
Contract Costs [Member]
Contract costs.
Equity [Abstract]
Entity Current Reporting Status
Entity Current Reporting Status
Minimum holding period
Minimum holding period.
Minimum Holding Period
Commitments and Contingencies Disclosure [Text Block]
Contingencies
Cash Flow Hedging [Member]
Cash Flow Hedging [Member]
Percentage of shares transferable.
Percentage of Shares Transferable
Percentage of shares transferable
Bauxite [Member]
Bauxite [Member]
Bauxite.
Product and Service
Product and Service [Axis]
Document Fiscal Period Focus
Document Fiscal Period Focus
Senior notes, interest percentage
Debt Instrument, Interest Rate, Stated Percentage
Entity Shell Company
Entity Shell Company
Legal Entity of Counterparty, Type [Axis]
Other Financial Information
Additional Financial Information Disclosure [Text Block]
Convertible Debt [Member]
Convertible Debt
Gas Supply Prepayment
Gas supply prepayment.
Gas supply prepayment
Cash and Cash Equivalent
Cash and Cash Equivalents, at Carrying Value, Total
Cash and cash equivalents
Cash and cash equivalents (L)
Business Combination Successive Annual Periods
Business combination successive annual periods.
Business combination successive annual periods
Certain Employee Obligations [Member]
Certain employee obligation.
Non-U.S. [Member]
Foreign Plan [Member]
Statement [Table]
Statement [Table]
Change in unrecognized net actuarial gain/loss and prior service cost/benefit related to pension and other postretirement benefits, Alcoa Corporation
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent
Noncurrent restricted cash
Restricted Cash, Noncurrent
Alcoa Corporation [Member]
Alcoa Corporation [Member]
Alcoa corporation.
Trento Equity Holdings SL [Member]
Trento Equity Holdings SL.
Increase (Decrease) in Receivables, Total
Increase (Decrease) in Receivables
(Increase) decrease in receivables
Payments to Acquire Businesses, Gross
Business combination, cash amount
Balance at beginning of period
Balance at end of period
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax
Statement [Line Items]
Statement [Line Items]
Business Combination [Domain]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)
Other comprehensive loss (unrealized)
Other comprehensive income (unrealized)
Other comprehensive loss (unrealized)
Entity Filer Category
Entity Filer Category
Settlement of certain other postretirement benefits
Settlement gain
Settlement of certain other postretirement benefits
Settlements
Settlements
Derivative instrument level 1 and 3.
Level 1 and 3 Derivative Instruments [Member]
Derivative Instrument Level1 And3 [Member]
Foreign Currency Translation Adjustments Reclassified to Accumulated Other Comprehensive Loss
Foreign currency translation adjustments reclassified to accumulated other comprehensive loss.
Foreign currency translation adjustments reclassified to AOCI
South Thirty Two Limited [Member]
South32 Limited.
South32 Limited [Member]
Liabilities and Equity
Total liabilities, mezzanine equity, and equity
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Sale of gross customer receivables
Sale of Gross Customer Receivables
Sale of Gross Customer Receivables
Restructuring Type
Restructuring Type [Axis]
Foreign currency translation adjustments, Alcoa Corporation
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent
Schedule of Carrying Values and Fair Values of Other Financial Instruments
Fair Value, by Balance Sheet Grouping [Table Text Block]
Hedging Relationship
Hedging Relationship [Axis]
Total amount reclassified from Accumulated other comprehensive loss, net of tax
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax
Increase (Decrease) in Accrued Taxes Payable, Total
Increase (Decrease) in Accrued Taxes Payable
Increase (decrease) in taxes, including income taxes
Revenue from External Customers by Products and Services [Table Text Block]
Schedule of Third-party Sales by Product Division
Derivative [Line Items]
Derivative [Line Items]
Cash and cash equivalents
Cash and Cash Equivalents, Fair Value Disclosure
Deferred Tax Assets, Valuation Allowance
Deferred tax assets, valuation allowance
Payments For Financial Contributions For The Divestiture Of Businesses
Payments for financial contributions for the divestiture of businesses.
Financial contributions for the divestiture of businesses
Effective federal statutory tax rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Schedule Of Estimate Timing Of Cash Outflows On Environmental Reserves Table [Text Block]
Tabular disclosure of estimate timing of cash outflows on environmental reserves.
Schedule of Estimate Timing of Cash Outflows from Environmental Reserves
Site Remediation at Previously Closed Site [Member]
Site remediation at previously closed site.
Other Noncash Income (Expense), Total
Other
Other Noncash Income (Expense)
Income Tax Authority
Income Tax Jurisdiction [Axis]
(Gain) Loss On Mark To Market Derivative Financial Contracts
(Gain) loss on mark-to-market derivative financial contracts.
Loss (gain) on mark-to-market derivative financial contracts
Income Tax Expense Benefit From Estimated Annualized Effective Tax Rate
Income tax expense (benefit) from estimated annualized effective tax rate.
Income tax expense
Income tax expense (benefit)
Geographical
Geographical [Domain]
Discrete Tax Benefit Expense
Discrete tax (benefit) expense.
Discrete tax (benefit) expense
Discrete tax expense
Income Taxes [Table]
Income Taxes [Table]
Income taxes.
Gain on Mark to Market Noncurrent Marketable Securities
Gain on mark to market noncurrent marketable securities.
Mark-to-market loss on noncurrent marketable securities (O)
Corporate expenses
Segment Reporting Information Corporate Expenses
Segment reporting information corporate expenses.
Japanese Yen Revolving Credit Facility [Member]
Japanese Yen Revolving Credit Facility [Member]
Japanese yen revolving credit facility.
Schedule of Inventory Components
Schedule of Inventory, Current [Table Text Block]
Additional capital
Additional Paid in Capital, Common Stock
Currency [Axis]
Trento Equity [Member]
Trento Equity.
Trento EQT [Member]
Net change in unrecognized gains/losses on cash flow hedges, Alcoa Corporation
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent
Disaggregation Of Revenue [Table]
Disaggregation of Revenue [Table]
Schedule of Computation of Basic and Diluted EPS Attributable to Alcoa Corporation Common Shareholders
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Investment, Name
Investment, Name [Axis]
Basic
Earnings Per Share, Basic
Earnings Per Share, Basic, Total
Repayments of Long-Term Debt
Repayments of Long-Term Debt, Total
Payments on debt (J)
Aluminum forecast sales
Aluminum Forecasted Sales Designated As Fair Value Hedges In Kilo Metric Ton
Aluminum forecasted sales designated as fair value hedges in kilo metric ton.
Pension and Other Postretirement Benefits
Retirement Benefits [Text Block]
Weighted average discount rate
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate
Amortization of net actuarial gain/loss and prior service cost/benefit
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax, Total
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Total
Foreign currency translation adjustments
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Other comprehensive income (loss)
Net loss from asset sales
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property
2026 (excluding the six months ended June 30, 2026)
Accrual for Environmental Loss Contingency, Undiscounted, to be Paid, Remainder of Fiscal Year
Revolving Credit Facility [Member]
Revolving Credit Facility [Member]
Retirement Plan Type
Retirement Plan Type [Domain]
Total current liabilities
Liabilities, Current
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]
Adjustments to reconcile net income to cash from operations:
Hedging Designation
Hedging Designation [Domain]
Restructuring and other charges, net
Restructuring And Other Charges Net
Restructuring and other charges net.
Finished goods
Inventory, Finished Goods, Net of Reserves
Unfavorable Favorable Impact Income Tax Expense Benefit
Unfavorable (favorable) impact income tax expense benefit.
Unfavorable tax impact related to losses in jurisdictions with no tax benefit
Unfavorable (favorable) tax impact related to losses in jurisdictions with no tax benefit
Joint Venture Formation, Fair Value of Joint Venture
Contribution to form the joint venture
Other [Member]
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member]
Consolidation Items
Consolidation Items [Domain]
Business combination aggregate payable cash contingent value
Business combination aggregate payable cash contingent value.
Tax expense
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax
Alcoa Corporation shareholders’ equity:
Equity, Attributable to Parent [Abstract]
Entity Small Business
Entity Small Business
Hedging Designation
Hedging Designation [Axis]
Increase (Decrease) in Accrued Liabilities, Total
Increase (Decrease) in Accrued Liabilities
Increase (decrease) in accrued expenses
Commodity Contract
Commodity Contract [Member]
Retained Earnings (Accumulated Deficit)
Retained Earnings (Accumulated Deficit), Total
Retained earnings (deficit)
Mineracao Rio Do Norte [Member]
Mineracao Rio Do Norte.
Preferred Stock [Member]
Preferred Stock [Member]
Offsetting [Abstract]
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Liability, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]
Net Income Loss Including Portion Attributable to Mezzanine Equity and Non-Controlling Interest
Net income loss including portion attributable to mezzanine equity and non-controlling interest.
Net (loss) income
Investments In Environmental Offsets Ending Year
Investments in environmental offsets ending year.
Investments in environmental offsets ending year
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Worsley Alumina [Member]
Worsley alumina.
Other Receivables [Member]
Other receivables.
Cost of goods sold (exclusive of expenses below)
Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization
Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization, Total
Amendment Flag
Amendment Flag
Product and Service
Product and Service [Domain]
Loss Contingencies [Line Items]
Loss Contingencies [Line Items]
Inventories
Inventory Disclosure [Text Block]
Investigation of Potential Contamination [Member]
Investigation of Potential Contamination [Member]
Investigation of ootential contamination.
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
CHESS Depositary Interests [Member]
C H E S S Depositary Interests [Member]
C H E S S Depositary Interests [Member]
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation
CASH PROVIDED FROM OPERATIONS
Commodity Sell Forwards [Member]
Commodity Sell Forwards [Member]
Commodity Sell Forwards.
South Africa [Member]
SOUTH AFRICA
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description
Foreign Currency Translation [Abstract]
Foreign currency translation
Common Stock [Member]
Common Stock [Member]
Six Point One Two Five Percentage Senior Notes Due Two Thousand And Twenty Eight [Member]
Six Point One Two Five Percentage Senior Notes Due Two Thousand And Twenty Eight [Member]
6.125% Senior Notes Due 2028 [Member]
6.125% Notes, due 2028 [Member]
Hedging Relationship
Hedging Relationship [Domain]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Beginning Balance
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Total
Less: accumulated depreciation, depletion, and amortization
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Schedule of Fair Values of Level 3 Derivative Instruments Recorded as Assets and Liabilities
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Sale Of Ownership Interest Under Agreement Exchange for Cash
Sale of ownership interest under agreement exchange for cash.
Sale of ownership interest under agreement exchange for cash
Contribution to joint venture
Payments to Acquire Interest in Joint Venture
Foreign Exchange Buy Forwards Undesignated [Member]
Foreign exchange buy forwards undesignated.
Foreign Exchange Buy Forwards Undesignated [Member]
Portion at Fair Value Measurement [Member] [Default]
Fair Value Disclosure Item Amounts [Default]
Portion at Fair Value Measurement [Member]
Payment for Pension Benefits
Pension contributions (K)
Entity Address, Address Line One
Entity Address, Address Line One
Fair Value Hierarchy and NAV
Fair Value Hierarchy and NAV [Axis]
EARNINGS PER SHARE ATTRIBUTABLE TO ALCOA CORPORATION COMMON SHAREHOLDERS (F):
Earnings Per Share [Abstract]
Total Segment Adjusted EBITDA
Segment Adjusted EBITDA
Adjusted Ebitda
Adjusted EBITDA.
Charge recorded in provision for income taxes to establish liability for estimated loss
Income Tax Examination, Estimate of Possible Loss
Derivative Assets
Total asset derivatives
Derivative Assets, Fair value
Derivative Asset
Energy [Member]
Energy [Member]
Energy.
Balance Sheet Location
Statement of Financial Position Location, Balance [Axis]
Net income (loss), Noncontrolling interest
Net Income (Loss) Attributable to Noncontrolling Interest, Total
Net Income (Loss) Attributable to Noncontrolling Interest
Net (income) loss attributable to noncontrolling interest
Less: Net income (loss) attributable to noncontrolling interest
Inventory Disclosure [Abstract]
Repayments of Senior Debt
Repayments of Senior Debt, Total
Repayment of senior debt
Midwest aluminum premium for first and last month
Midwest Aluminum Premium For First and Last Month
Midwest aluminum premium for first and last month.
Document Type
Document Type
Midwest aluminum premium
Midwest Aluminum Premium
Midwest aluminum premium.
Aligroup Acquisition [Member]
Aligroup Acquisition [Member]
AliGroup Acquisition.
Business disposition.
Business Disposition [Line Items]
Business Disposition [Line Items]
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Entity Central Index Key
Entity Central Index Key
Minimum members required for strategic risk management committee.
Minimum Members Required For Strategic Risk Management Committee
Minimum members required for strategic risk management committee
Net change in cash and cash equivalents and restricted cash
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation
Subsequent Event Type [Domain]
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax, Total
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax
Tax benefit (expense)
Tax (expense) benefit
Other
Segment Reporting Information Other Income Expense Net
Segment reporting information other income expense net.
Common Stock, Par or Stated Value Per Share
Value per share
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Total Other comprehensive income (loss), net of tax, Alcoa Corporation
Other comprehensive income (loss) (G)
LIABILITIES
Liabilities [Abstract]
Series A Convertible Preferred Stock, Par Value $0.01 Per Share [Member]
Series A Convertible Preferred Stock [Member]
Series A Convertible Preferred Stock [Member]
Series A Convertible Preferred Stock
Retirement Plan Sponsor Location
Retirement Plan Sponsor Location [Domain]
Prepaid pension benefit
Prepaid Pension Cost Non Current
Prepaid Pension Cost Non current.
Euro Power Purchases [Member]
Euro Member Countries, Euro
Alcoa Corporation [Member]
Parent [Member]
Debt Disclosure [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Total
Net change in unrecognized gains/losses on cash flow hedges
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax
Derivative [Table]
Derivative [Table]
Alcoa Nederland holding BV.
Alcoa Nederland Holding B V [Member]
Alcoa Nederland Holding BV [Member]
ANHBV [Member]
Commodity Buy Forwards Electricity [Member]
Commodity buy forwards electricity.
Other non operating income expense.
Other Non Operating Income Expense [Line Items]
Other Non Operating Income Expense [Line Items]
Fair Value [Member]
Estimate of Fair Value Measurement [Member]
Bridge Term Loan Credit Facility [Member]
Bridge Term Loan Credit Facility.
Massena, New York [Member]
Massena New York [Member]
Massena, New York.
Cost of Goods Sold [Member]
Cost of Sales [Member]
Ownership
Ownership [Domain]
Current Fiscal Year End Date
Current Fiscal Year End Date
Income tax benefits recorded in Cost of goods sold
Income Tax Benefits Recorded in Cost of Goods Sold
Income tax benefits recorded in cost of goods sold.
Debt Instrument [Table]
Schedule of Long-Term Debt Instruments [Table]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Total
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures
Carrying value of investment
Investments
Noncurrent restricted cash
Restricted Cash and Cash Equivalent, Noncurrent
Restricted Cash and Cash Equivalents, Noncurrent, Total
Additions To Long Term Debt Issued Less Issuance Discount
Long term debt issued less issuance discount.
Additions to debt (J)
Schedule of Cash and Cash Equivalents and Restricted Cash
Schedule Of Cash And Cash Equivalents And Restricted Cash Table [Text Block]
Schedule of cash and cash equivalents and restricted cash table.
Document Quarterly Report
Document Quarterly Report
Common Stock, Par Value $0.01 Per Share {Member]
Common Stock, Par Value Zero Point Zero One Per Share [Member]
Common stock, par value zero point zero one per share.
Receivables [Abstract]
Entity Address, State or Province
Entity Address, State or Province
Net Additional Asset Retirement Obligations and Environmental Remediation [Member]
Net additional asset retirement obligations and environmental remediation.
Investment, Name
Investment, Name [Domain]
Preferred stock outstanding
Preferred Stock, Shares Outstanding
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Comprehensive income (loss), Alcoa Corporation
Geographical
Geographical [Axis]
Joint Venture Formation
Joint venture formation.
Joint venture formation (C)
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions, Total
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions
Equity loss (income), net of dividends
Operating supplies
Inventory, Supplies, Net of Reserves
Embedded Credit Derivative [Member]
Embedded Credit Derivative [Member]
Embedded credit derivative.
Ownership Interests In Joint Venture
Ownership interests in joint venture.
Ownership interest in joint venture
Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration]
Investments In Environmental Offsets Impacts Caused By Minining Developement And Coservation Programs
Investments in environmental offsets impacts caused by minining developement and Conservation programs.
Investments in environmental offsets impacts caused by minining developement and Conservation programs
Natural Gas [Member]
Energy Related Derivative [Member]
Energy Contracts [Member]
Deferred income taxes
Deferred Income Tax Assets, Net
Other Postretirement Benefits [Member]
Other Postretirement Benefits Plan [Member]
Long-term debt, less amount due within one year
Long-Term Debt, Fair Value
Subsequent Event [Member]
Subsequent Event [Member]
Other assets, noncurrent, total
Other Assets, Noncurrent
Other noncurrent assets (O)
Preferred stock dividends per share
Preferred Stock, Dividends, Per Share, Cash Paid
Ongoing remediation work.
Ongoing Remediation Work [Member]
Ongoing Remediation Work [Member]
Accumulated other comprehensive (loss) income [Member]
AOCI Attributable to Parent [Member]
Derivative Liabilities
Total liability derivatives
Derivative Liabilities
Derivative Liabilities, Fair value
Business Combination, Consideration Transferred
Business Combination, Consideration Transferred, Total
Aggregate purchase consideration
Preferred Stock, Value, Issued
Preferred stock
Selling, general administrative, and other expenses
Selling, General and Administrative Expense
Selling, General and Administrative Expense, Total
Amount of (loss) gain expected to be recognized into earnings over the next 12 months
Cash Flow Hedge Gain (Loss) to be Reclassified within 12 Months
Minimum [Member]
Minimum [Member]
Schedule of Changes in Carrying Value of Recorded Environmental Remediation Reserves
Schedule Of Changes In Carrying Value Of Recorded Environmental Remediation Reserves Table [Text Block]
Tabular disclosure of changes in carrying value of recorded environmental remediation reserves.
Financial Instrument
Financial Instrument [Axis]
Current assets:
Assets, Current [Abstract]
Level 3 Derivative Instruments [Member]
Derivative Instrument Level3 [Member]
Derivative instrument level 3.
Two Thousand Twenty Five Action Plan One Member
Two thousand twenty five action plan one.
2025 Plan Actions [Member]
Action #1 [Member]
Level 3 [Member]
Fair Value, Inputs, Level 3 [Member]
Foreign currency translation and other
Accrual For Environmental Loss Contingencies Foreign Currency Translation Gain Loss And Other
Accrual for environmental loss contingencies foreign currency translation gain (loss) and other.
Amounts borrowed under the credit facility
Proceeds from Long-Term Lines of Credit
Segment Reporting [Abstract]
Environmental remediation (O)
Environmental remediation (N)
Current liabilities:
Liabilities, Current [Abstract]
Restructuring and Other Charges, Net
Restructuring and Related Activities Disclosure [Text Block]
Schedule of Restructuring and Other Charges, Net by Reportable Segments, Pretax
Schedule Of Restructuring Charges Net Before Income Tax Not Allocated To Reportable Segment Table [Text Block]
Schedule of restructuring charges, net before income tax not allocated to reportable segment.
Huntly Australia [Member]
Huntly Australia.
Bauxite and alumina
Other Inventory, Net of Reserves
Accounts Receivable, after Allowance for Credit Loss, Current, Total
Accounts Receivable, after Allowance for Credit Loss, Current
Receivables from customers (H)
Joint venture consideration amount
Joint venture consideration amount.
Total consideration
Interest Rate Contracts [Member]
Interest Rate Contract [Member]
Commitments and Contingencies
CONTINGENCIES AND COMMITMENTS (O)
Other noncurrent liabilities and deferred credits
Deferred Credits and Other Liabilities, Noncurrent
Service cost
Defined Benefit Plan, Service Cost
Alumina [Member]
Alumina [Member]
Alumina.
Foreign currency translation adjustments, Noncontrolling interest
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest
Work-in-process
Inventory, Work in Process, Net of Reserves
Forecast [Member]
Forecast [Member]
Short-Term Debt, Total
Short-term borrowings
Short-Term Debt
Restructuring and Other Charges Benefit Net
Restructuring and other charges (benefit) net.
Restructuring and other charges, net (D)
Restructuring and other charges, net
Restructuring and other charges, net (D)
Marketable Securities, Noncurrent
Noncurrent marketable securities
Noncurrent marketable securities (C & L)
Other Sites [Member]
Other Sites [Member]
Other sites.
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]
Activity and Reserve Balances for Restructuring and Other Charges
U.S. dollar Aluminum Sales, Australia [Member]
AUSTRALIA
Australia [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax, Total
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax
Total Other comprehensive income before reclassifications, net of tax
Net income (loss)
Net loss
Net income
Net income
Aluminum [Member]
Aluminum [Member]
Aluminum.
Loss Contingencies [Table]
Loss Contingencies [Table]
Adjusted operating costs
Adjusted operating costs.
Adjusted operating costs
Weighted Average Number of Shares Outstanding, Basic, Total
Weighted Average Number of Shares Outstanding, Basic
Average shares outstanding - basic
Scenario
Scenario [Axis]
Document Information [Line Items]
Temporary Equity [Abstract]
MEZZANINE EQUITY
2029 [Member]
Two Thousand Twenty Nine [Member]
Two thousand twenty nine.
Payment terms
Payment Terms
Payment Terms.
Investments In Environmental Offsets Starting Year
Investments in environmental offsets starting year.
Investments in environmental offsets starting year
Segments [Axis]
Segments
Liabilities incurred
Liabilities incurred
Accrual for Environmental Loss Contingencies, Charges to Expense for New Losses
Third-party sales
Segment Reporting Information Unrelated Party Sales
Segment reporting information unrelated party sales.
San Ciprian Joint Venture [Member]
San Ciprian Joint Venture.
Subsequent Events
Subsequent Events [Text Block]
Purchased raw materials
Inventory, Raw Materials, Net of Reserves
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Total
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax
Total Other comprehensive income (loss)
San Ciprian (Spain) Aluminum Smelter [Member]
San Ciprian Aluminum Smelter [Member]
San Ciprian Aluminum Smelter.
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition, Total
Stock-based compensation
APIC, Share-Based Payment Arrangement, Increase for Cost Recognition
Boddington Bauxite Mine [Member]
Boddington Bauxite Mine
Payments to Acquire Investments, Total
Additions to investments
Payments to Acquire Investments
Idled Bayside Smelter Property [Member]
Idled Bayside Smelter Property.
Basis of Presentation
Basis of Accounting, Policy [Policy Text Block]
Statement of Stockholders' Equity [Abstract]
Alcoa Special Purpose Vehicle [Member]
Alcoa Special Purpose Vehicle.
Type of Restructuring
Type of Restructuring [Domain]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Disclosure [Line Items]
Foreign currency losses (gains), net
Foreign Currency Transaction Gain (Loss), before Tax, Total
Gain (Loss), Foreign Currency Transaction, before Tax
Entity Address, Address Line Two
Entity Address, Address Line Two
Derivatives and Other Financial Instruments
Fair Value Disclosures [Text Block]
Schedule of Outstanding Quantities of Derivative Instruments
Schedule Of Outstanding Quantities Of Derivative Instruments Table [Text Block]
Schedule of outstanding quantities of derivative instruments.
Debt Instrument, Name [Domain]
Manicouagan Power Limited Partnership [Member]
Manicouagan Power Limited Partnership [Member]
Manicouagan Power Limited Partnership [Member]
Third-Party Sales [Member]
Third Party Sales [Member]
Third party sales.
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]
Deferred mining costs, net
Deferred Costs, Noncurrent
Deferred Costs, Noncurrent, Total
Other segment items
Segment Reporting, Other Segment Item, Amount
Defined Benefit Pension Plans Net Periodic Benefit Cost
Defined benefit pension plans net periodic benefit cost.
Net periodic pension benefit cost (K)
Interest expense
Interest Expense, Total
Interest expense
Interest Expense, Operating and Nonoperating
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Entity
Entity [Domain]
Transformation
Segment Reporting Information Transformation
Segment Reporting Information Transformation.
Credit Facility
Credit Facility [Axis]
Equity Method Investment, Ownership Percentage
Percentage of ownership held
Other Noncurrent Assets [Member]
Other Noncurrent Assets [Member]
Restructuring Plan
Restructuring Plan [Axis]
Related Party
Related and Nonrelated Parties [Axis]
Foreign Jurisdiction [Member]
Foreign Tax Jurisdiction [Member]
Foreign [Member]
Pension Benefits [Member]
Pension Plan [Member]
Reinvested Collection From Previously Sold Receivables
Reinvested collections from previously sold receivables
Reinvested collection from previously sold receivables.
Environmental remediation work completion period
Environmental Remediation Work Completion Period
Environmental remediation work completion period.
Foreign Exchange Contract [Member]
Foreign Exchange Contracts [Member]
Entity Address, City or Town
Entity Address, City or Town
Reversals and other
Restructuring Reserve, Translation and Other Adjustment
Schedule Of Other Non operating Income Expense [Table]
Schedule Of Other Non Operating Income Expense [Table]
Schedule Of Other Non Operating Income Expense [Table]
Number of reportable segments
Number of Reportable Segments
Security Exchange Name
Security Exchange Name
Credit Facility
Credit Facility [Domain]
Redeemable Noncontrolling Interest, Equity, Carrying Amount
Redeemable Noncontrolling Interest, Equity, Carrying Amount, Total
Noncontrolling interest (C)
Ending Balance
Beginning Balance
Property, Plant and Equipment, Gross, Ending Balance
Property, Plant and Equipment, Gross, Beginning Balance
Property, Plant and Equipment, Gross, Total
Properties, plants, and equipment
Property, Plant and Equipment, Gross
Intersegment Eliminations [Member]
Intersegment Eliminations [Member]
Sale of investments
Proceeds from Sale of Investment Projects
Proceeds received from sale of non-core investment
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest
Income before income taxes
Income before income taxes
Mezzanine Equity Non-Controlling Interest [Member]
Mezzanine equity non-controlling interest.
Non-controlling Interest [Member]
Mezzanine Equity Non-Controlling Interest [Member]
Net effect of tax withholding for compensation plans and exercise of stock options
Net Effect Of Tax Withholding, Share Based Compensation Arrangement and Stock Options Exercised
Net Effect Of Tax Withholding, Share Based Compensation Arrangement and Stock Options Exercised
ANH Holdings One B V [Member]
ANH Holdings One B V
Intersegment sales
Segment Reporting Information Intersegment Revenues
Segment reporting information intersegment revenues.
Contract with Customer, Duration [Domain]
Measurement Input Type
Measurement Input Type [Domain]
Retirement Plan Sponsor Location
Retirement Plan Sponsor Location [Axis]
Number of remediation projects
Number Of Remediation Projects
Number of remediation projects.
2027 [Member]
Two Thousand Twenty Seven [Member]
Two thousand twenty seven.
Net change from periodic revaluations
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax
Unrealized gain (loss) recognized in Other comprehensive income (loss)
Inventory sold
Inventories, total
Inventory, Net
Inventories (I)
Cash and cash equivalents and restricted cash, total
Cash and cash equivalents and restricted cash at beginning of year
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD
Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation
MWh of Energy Needed to Produce Forecasted Mt of Aluminum at Rate of 4 Million MWh Per Year [Member]
M Wh Of Energy Needed To Produce Forecasted Mt Of Aluminum At Rate Of4 Million M Wh Per Year [Member]
MWh of Energy Needed to Produce Forecasted Mt of Aluminum at Rate of 4 Million MWh Per Year.
Measurement Basis
Measurement Basis [Axis]
Statistical Measurement
Statistical Measurement [Domain]
2028 [Member]
Two Thousand Twenty Eight [Member]
Two thousand twenty eight.
Total current assets
Assets, Current
Receivables previously secured by credit facility
Receivables Purchase Agreement
Reflects the maximum aggregate revolving value of trade receivables which can be sold.
Document Period End Date
Document Period End Date
Receivables Purchase Agreement [Member]
Receivables Purchase Agreement Member
Receivables purchase agreement.
Other Income and Expenses [Abstract]
Fair Value Hierarchy and NAV
Fair Value Hierarchy and NAV [Domain]
Other
Other Assets, Miscellaneous, Noncurrent
Restricted cash available for capital improvments
Restricted cash available for capital improvments
Restricted cash available for capital improvments.
Statement of Financial Position [Abstract]
Two Thousand Twenty Six [Member]
Two thousand twenty six.
2026 [Member]
Class of Stock [Axis]
Class of Stock
Remaining Ownership Interest Amount
Purchase price for remaining ownership amount.
Purchase price for remaining ownership amount
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax, Total
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax
Tax benefit (expense)
Net Assets Included In Joint Venture Formation
Net assets included in joint venture formation.
Net assets included in joint venture formation
Derivatives Not Designated as Hedging Instruments [Member]
Not Designated as Hedging Instrument [Member]
Total liabilities
Liabilities
Derivative instruments, expiration month and year
Derivative Instrument Maturity Month And Year
Derivative instrument, maturity month and year.
Financial Instruments
Financial Instruments [Domain]
Bridge financing facility maximum commitment amount
Bridge financing facility maximum commitment amount.
Asset Retirement Obligations, Noncurrent, Total
Asset Retirement Obligations, Noncurrent
Asset retirement obligations
Non Rule 10b51 Arr Modified [Flag]
Non rule 10b51 arr modified flag.
Non Rule 10b51 Arr Modified Flag
All Currencies [Domain]
Real Estate Properties
Real Estate Properties [Domain]
Expected return on plan assets
Defined Benefit Plan, Expected Return (Loss) on Plan Assets
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments, Gain (Loss) [Line Items]
Restricted cash
Restricted Cash, Total
Restricted Cash
Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Input Reconciliation [Table]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table]
Foreign Exchange Forward
Foreign Exchange Forward [Member]
Outstanding Energy Derivative Instruments
Outstanding energy derivative instruments.
Outstanding energy derivative instruments
Weighted Average Number of Shares Outstanding, Diluted
Average shares outstanding - diluted
Norway [Member]
Euro Power Purchases, Norway [Member]
NORWAY
Entity File Number
Securities Act File Number
Dividends paid on Alcoa common stock
Payments of Ordinary Dividends, Common Stock
Domestic Plan
Domestic Plan [Member]
Basis of Presentation
Basis of Accounting [Text Block]
Cover [Abstract]
Measurement Input Type
Measurement Input Type [Axis]
Federal value added tax credits
Value Added Tax Receivable
Prepaid expenses and other current assets
Prepaid Expense and Other Assets, Current
Taxes Payable, Current, Total
Taxes, including income taxes
Taxes Payable, Current
Accured tax liabilty
Change in unrecognized net actuarial gain/loss and prior service cost/benefit related to pension and other postretirement benefits, Noncontrolling interest
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Noncontrolling Interest
MWh of Energy Needed to Produce Forecasted Mt of Aluminum at Rate of 2 Million MWh Per Year.
M Wh Of Energy Needed To Produce Forecasted Mt Of Aluminum At Rate Of2 Million M Wh Per Year [Member]
MWh of Energy Needed to Produce Forecasted Mt of Aluminum at Rate of 2 Million MWh Per Year [Member]
Value added tax receivable
Value added tax receivable
Income Tax Credits and Adjustments
Scenario
Scenario [Domain]
Liability, Defined Benefit Pension Plan, Noncurrent
Accrued pension benefits (K)
Number of Operating Segments
Number of operating segments
Aluminum Contracts [Member]
Aluminum Contracts [Member]
Aluminum contracts.
Segment Information
Segment Reporting Disclosure [Text Block]
Contract with Customer, Duration [Axis]
Active or future remediation for significant sites
Accrual Environmental Loss Active Remediation Future Remediation For Significant Individual Sites
Accrual environmental loss active remediation future remediation for significant individual sites.
Net change in unrecognized gains/losses on cash flow hedges, Noncontrolling interest
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Noncontrolling Interest
Corporate [Member]
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Total sales
Revenue from Contract with Customer, Including Assessed Tax
Gain on Sale of Investments
Gain on sale of investments
Unsold customer receivables as collateral sold receivables
Unsold Customer Receivables As Collateral Sold Receivables
Unsold Customer Receivables As Collateral Sold Receivables.
Cash flow hedges (M)
Effect of Cash Flow Hedges on Results of Operations [Abstract]
Received Income Tax Benefit Including Interest Income From Prior Tax Credit
Received income tax benefit including interest income from prior tax credit.
Received income tax benefit including interest income from prior tax credit
Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table]
Derivative Instruments, Gain (Loss) [Table]
Gain (Loss) on Disposition of Assets, Total
Net gain from asset sales
Gain (Loss) on Disposition of Assets
Net loss from investing activities - asset and investment sales (O)
Ownership
Ownership [Axis]
Financial Contracts [Member]
Finance Related Derivative [Member]
Finance related derivative.
Severance and Employee Termination Costs [Member]
Employee Severance [Member]
Comprehensive Income (Loss) Note [Text Block]
Accumulated Other Comprehensive Loss
Curtailments
Curtailment loss
Curtailment of certain other postretirement benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed
Debt instrument redemption price percentage of principal amount redeemed
Noncurrent portion of the reserve
Restructuring Reserve, Noncurrent
Carrying Value [Member]
Reported Value Measurement [Member]
Change in unrecognized net actuarial gain/loss and prior service cost/benefit related to pension and other postretirement benefits
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax, Total
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
Total Other comprehensive income
Other Receivables, Net, Current, Total
Other receivables
Other Receivables, Net, Current
Repurchase of inventory related to agreement
Repurchase of Inventory Related to Agreement
Repurchase of inventory related to agreement.
Twenty Twenty Six Restructuring Plan [Member]
Twenty Twenty Six Restructuring Plan.
2026 Restructuring Plans Action [Member]
Derivative forward energy price for first and last month
Derivative Forward Energy Price For First and Last Month
Derivative forward energy price for first and last month.
Provision for depreciation, depletion, and amortization
Depreciation, Depletion and Amortization, Total
Provision for depreciation, depletion, and amortization
Depreciation, depletion, and amortization
Depreciation, Depletion and Amortization
Amortization of prior service benefit
Amortization of prior service cost
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)
Document Transition Report
Document Transition Report
Research and development expenses
Research and Development Expense
Research and Development Expense, Total
Schedule of Income Taxes
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Comprehensive income (loss)
Net gain on mark-to-market derivative instruments
Unrealized Gain (Loss) on Derivatives
Net gain loss on mark-to-market derivative instruments
Net loss (gain) on mark-to-market derivative instruments
Statement of Cash Flows [Abstract]
Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract]
Effect of dilutive securities:
2036 [Member]
Two Thousand Thirty Six [Member]
Two thousand thirty six.
Other financial information.
Other Financial Information [Abstract]
Accounts and Financing Receivables [Table]
Earnings Per Share
Earnings Per Share [Text Block]
Discontinued Operations and Disposal Groups [Abstract]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value
Fair value measurement, Assets, Beginning balance
Fair value measurement, Assets, Ending balance
Consolidated net income attributable to Alcoa Corporation
Increase (Decrease) in Inventories, Total
Increase (Decrease) in Inventories
Increase in inventories
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax, Total
Balance at beginning of period
Balance at end of period
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax
Interrelationship of Forward Energy Price, LME Forward Price and Consumer Price Index [Member]
Interrelationship Of Forward Energy Price L M E Forward Price And Consumer Price Index [Member]
Interrelationship of forward energy price, LME forward price and consumer price index.
Intangibles, net
Other Intangible Assets, Net
Alumar Refinery.
Alumar Refinery [Member]
Alumar Refinery [Member]
Schedule of Segment Adjusted EBITDA to Consolidated Net Income (Loss) Attributable to Alcoa Corporation
Schedule Of Segment Reporting Information To Consolidate Net Income Loss Attributable To Parent Table [Text Block]
Schedule of segment reporting information to consolidate net income loss attributable to parent.
MWh of Energy Needed to Produce Forecasted Mt of Aluminum at Rate of 18 Million MWh Per Year [Member]
M Wh Of Energy Needed To Produces Forecasted Mt Of Aluminum At Rate Of18 Million M Wh Per Year [Member]
MWh of energy needed to produces forecasted Mt of aluminum at rate of 18 million MWh per year.
Fair Value Inputs Level 1 and Level 2 [Member]
Fair value inputs level 1 and level 2.
Other
Proceeds from (Payment for) Other Financing Activity
Defined benefit plan number of plan participants affected.
Defined Benefit Plan Number Of Plan Participants Affected
Number of employees affected the change in defined benefit plans
Number of affected plan participants
Schedule of Quantitative Information for Level 3 Derivative Contracts
Fair Value Inputs Assets Liabilities Quantitative Information Table [Text Block]
Tabular disclosure of quantitative information about the inputs used in the fair value measurement of assets and liabilities. This disclosure may include, but is not limited to, the fair value of the asset or liability, valuation technique used to measure fair value, the inputs used to measure fair value, the ranges of the inputs, and the weighted averages of the inputs.
ASSETS
Assets [Abstract]
Income Tax Authority, Name
Income Tax Authority, Name [Axis]
Increase (Decrease) in Prepaid Expense and Other Assets
Decrease in prepaid expenses and other current assets
Restructuring and Related Activities [Abstract]
Document Fiscal Year Focus
Document Fiscal Year Focus
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
Summary of Changes in Accumulated Other Comprehensive Loss by Component
INVESTING ACTIVITIES
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]
Retirement Benefits [Abstract]
Accounts Payable, Current, Total
Accounts payable, trade
Accounts Payable, Current
Payments of Ordinary Dividends, Preferred Stock and Preference Stock
Dividends paid on Alcoa preferred stock
Acquisition of Noncontrolling interest
Acquisition of Noncontrolling interest
Acquisition of noncontrolling interest (C)
Ticking Fee Percentage Paid Per Annum
Ticking fee percentage paid per annum.
Ticking fee percentage paid per annum
Components of Net Periodic Benefit Cost
Schedule of Net Benefit Costs [Table Text Block]
Increase (decrease) to other noncurrent assets
Decrease to other noncurrent assets
Increase in noncurrent assets
SPAIN
Spain [Member]
San Ciprian (Spain) Strike [Member]
Accounting Standards Update and Change in Accounting Principle [Abstract]
Percentage of debt yield credit spread
Derivative, Basis Spread on Variable Rate
Restructuring Cost and Reserve [Line Items]
Restructuring Cost and Reserve [Line Items]
Balance at beginning of period
Balance at end of period
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax
Commodity Buy Forwards [Member]
Commodity Buy Forwards [Member]
Commodity Buy Forwards.
Fair Value Disclosures [Abstract]
Commitments and Contingencies Disclosure [Abstract]
Contingencies
Estimated Spread Between The Respective 30-Year Debt Yield Of Alcoa Corporation And The Counterparty [Member]
Estimated Spread Between The Respective Thirty Year Debt Yield Of Alcoa Corporation And The Counterparty [Member]
Estimated spread between the respective thirty year debt yield of Alcoa Corporation and the counterparty.
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Power Contract [Member]
Power Related Derivative [Member]
Power Related Derivative [Member].
Real Estate Property Ownership
Real Estate Property Ownership [Axis]
Long-Term Line of Credit
Line of credit facility, amounts outstanding
Debt Instrument [Axis]
Derivative Instrument
Derivative Instrument [Axis]
Interest cost
Defined Benefit Plan, Interest Cost
Rule 10b51 Arr Modified [Flag]
Rule 10b51 arr modified flag.
Rule 10b51 Arr Modified Flag
Long-Term Debt and Lease Obligation, Current
Long-Term Debt and Lease Obligation, Current, Total
Long-term debt due within one year (J & L)
Interrelationship of Forward Energy Price and Contract Price and Estimated MW of Renewable Energy Produced [Member]
Interrelationship of forward energy price and contract price and estimated MW of renewable energy produced.
Interrelationship of Forward Energy Price and Contract Price and Estimated MW of Renewable Energy Produced [Member]
Debt Instrument, Fair Value Disclosure, Total
Long-term debt due within one year
Debt Instrument, Fair Value Disclosure
CASH USED FOR INVESTING ACTIVITIES
Cash Provided by (Used in) Investing Activity, Including Discontinued Operation
Schedule Of Business Dispositions By Disposition [Table]
Schedule Of Business Dispositions By Disposition [Table]
Schedule Of Business Dispositions By Disposition [Table]
Fair value measurement with unobservable inputs reconciliation recurring basis asset increase decrease settlements and other.
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Increase Decrease Settlements And Other
Settlements and other
Value added tax credits
Value Added Tax Receivable, Noncurrent
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic, Total
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic
Less: Undistributed earnings allocated to preferred stock
Undistributed earnings
Saudi Arabia Joint Venture.
Saudi Arabia Joint Venture [Member]
Saudi Arabia Joint Venture [Member]
Title of 12(b) Security
Title of 12(b) Security
Schedule Of Segment Reporting Information By Segment [Table]
Schedule of Segment Reporting Information, by Segment [Table]
Segment reporting information for reported assets.
Segment Reporting Information Reported Assets
Segment assets
Related Party
Related and Nonrelated Parties [Domain]
Income Taxes
Income Tax Disclosure [Text Block]
Income tax benefits due to inflation reduction act tax credits
Income Tax Benefits due to Inflation Reduction Act Tax Credits
Income tax benefits due to inflation reduction act tax credits.
Cash collections from previously sold receivables yet to be reinvested
Cash Collections From Previously Sold Receivables Yet to be Reinvested
Cash collections from previously sold receivables yet to be reinvested.
Investments In Environmental Offsets Associated Cash Outlays Expected Year
Investments in environmental offsets associated cash outlays expected year.
Investments in environmental offsets associated cash outlays expected year
Accounts Payable [Member]
Document Information [Table]
Restructuring Plan [Domain]
Restructuring Plan
Legal Entity
Legal Entity [Axis]
Commodity Buy Forwards Natural Gas [Member]
Commodity buy forwards natural gas.
Changes in assets and liabilities, excluding effects of divestitures and foreign currency translation adjustments:
Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]
Income Tax Disclosure [Abstract]
Foreign Exchange Sell Forwards [Member]
Foreign Exchange Sell Forwards [Member]
Foreign Exchange Sell Forwards [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table]
Fair Value, Recurring and Nonrecurring [Table]
Borrowings of inventory related to agreement
Short term borrowings of inventory related to agreement.
Short Term Borrowings Of Inventory Related To Agreement
Additional Paid-in Capital [Member]
Additional Capital [Member]
San Ciprian Smelter.
San Ciprian Smelter [Member]
San Ciprián Smelter [Member]
AWAB [Member]
Alcoa World Alumina Brasil (AWAB).
Alcoa World Alumina Brasil [Member]
Alcoa World Alumina Brasil [Member]
Income Statement Location
Statement of Income Location, Balance [Axis]
Trading Symbol
Trading Symbol
Extinguishment of Debt [Axis]
Subsequent Event Type [Axis]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax
Tax benefit
Tax benefit
Employee-related Liabilities, Current, Total
Accrued compensation and retirement costs
Employee-related Liabilities, Current
FINANCING ACTIVITIES
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]
Sale Of Ownership Interest Under Agreement Exchange For Issuance per Share
Sale of ownership interest under agreement exchange for issuance per share.
Sale of ownership interest under agreement exchange for issuance per share
Restructuring and other charges, net
Restructuring and Other Charges Net [Member]]
Restructuring and Other Charges, Net [Member]
Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends
Stock units
Equity Components
Equity Components [Axis]
Counterparty [Member]
Individual Counterparty [Member]
Segment Reporting Information Equity In Net Income Of Equity Method Investees Of The Segments
Segment reporting information equity in net income of equity method investees of the segments.
Equity income (loss)
Other expenses (income), net
Nonoperating Income (Expense), Total
Nonoperating Income (Expense)
Other (expenses) income, net (O)
Other expenses (income), net (O)
Remediation reserve balance, current
Accrued Environmental Loss Contingencies, Current
Equity Component
Equity Component [Domain]
Proceeds from Noncontrolling Interests
Contributions from noncontrolling interest (C)
Business Combination [Axis]
Foreign Exchange Sell Forwards Undesignated [Member]
Foreign Exchange Sell Forwards Undesignated.
Foreign Exchange Sell Forwards Undesignated [Member]
Twenty Twenty Five Restructuring Plan [Member]
Twenty Twenty Five Restructuring Plan.
2025 Restructuring Plans Action [Member]
Statement of Comprehensive Income [Abstract]
Statement of Comprehensive Income [Abstract]
Maximum [Member]
Maximum [Member]
Derivatives Designated as Hedging Instruments [Member]
Designated as Hedging Instrument [Member]
Statistical Measurement
Statistical Measurement [Axis]
Capital expenditures
Segment Reporting Information Capital Expenditures
Segment Reporting Information Capital Expenditures
Common stock
Common Stock, Value, Issued
Sale of ownership interest under agreement exchange for issuance shares
Sale of Ownership Interest under Agreement Exchange for Issuance Shares
Sale of ownership interest under agreement exchange for issuance shares.
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest, Total
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest
Total Other comprehensive income (loss), net of tax, Noncontrolling interest
Line of Credit Facility, Expiration Date
Unsecured revolving credit facility maturity date
Derivative Assets Current
Total asset derivatives
Fair value of derivative instruments (L)
Outstanding Alumina Derivative Instruments
Outstanding alumina derivative instruments.
Outstanding alumina derivative instruments
Principles of Consolidation
Consolidation, Policy [Policy Text Block]
Total equity
Equity, Including Portion Attributable to Noncontrolling Interest
Beginning Balance
Ending Balance
Segment Reporting Information Equity Method Investments
Segment Reporting Information Equity Method Investments
Equity investments
Cash proceeds from financial institution
Proceeds from Issuance of Financial Services Obligations
Legal Entity Type of Counterparty [Domain]
Derivative Instrument Level1 [Member]
Level 1 Derivative Instruments [Member]
Derivative instrument level 1.
Other [Member]
Other Products [Member]
Other Products [Member]
Other products.
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest, Total
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Comprehensive income (loss), Noncontrolling interest
Foreign Exchange Buy Forwards [Member]
Foreign Exchange Buy Forwards [Member]
Foreign Exchange Buy Forwards [Member]
Payments related to tax withholding on stock-based compensation awards
Payment, Tax Withholding, Share-Based Payment Arrangement
Cash payments
Payments against the reserve
Accrual for Environmental Loss Contingencies, Payments
Intersegment eliminations
Intersegment eliminations
Segment Reporting Information Intersegment Eliminations
Segment reporting information intersegment eliminations
Addy, Washington [Member]
Addy Washington [Member]
Addy Washington.
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Table]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Entity Registrant Name
Entity Registrant Name
Debt
Debt Disclosure [Text Block]
Estimated annualized effective tax rate
Estimated Annualized Effective Tax Rate
Estimated annualized effective tax rate.
Noncurrent income taxes
Accrued Income Taxes, Noncurrent
Liability, Other Postretirement Defined Benefit Plan, Noncurrent
Accrued other postretirement benefits (K)
Other, net
Other Nonoperating Income (Expense), Total
Other Nonoperating Income (Expense)
Accumulated Other Comprehensive Income Loss [Table]
Accumulated Other Comprehensive Income (Loss) [Table]
Subsequent Events [Abstract]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Schedule of Other Expenses (Income), Net
Schedule of Other Nonoperating Income (Expense) [Table Text Block]
Income Tax Expense (Benefit)
Income taxes
Provision for income taxes
Provision for income taxes
Provision for income taxes
Common stock dividends per share
Common Stock, Dividends, Per Share, Cash Paid
Sales [Member]
Sales [Member]
Non-controlling interest, ownership percentage
Subsidiary, Ownership Percentage, Noncontrolling Owner
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Settlements and other
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Increase Decrease Settlements And Other
Fair value measurement with unobservable inputs reconciliation recurring basis liability increase decrease settlements and other.
Unrealized gain (loss) in accumulated other comprehensive loss
Accumulated other comprehensive loss (G)
Accumulated Other Comprehensive Income (Loss), Net of Tax
Total Accumulated other comprehensive (loss) income
Consolidation Items
Consolidation Items [Axis]
Cash payments
Payments for Restructuring
Cash payment for restructuring
Payments to Acquire Property, Plant, and Equipment, Total
Capital expenditures
Payments to Acquire Property, Plant, and Equipment
Payment for (Proceeds from) Other Investing Activity
Other
Total assets
Assets
Alumar Smelter.
Alumar Smelter [Member]
Alumar Smelter [Member]
Income Statement [Abstract]
Retirement Plan Name [Domain]
Schedule Of Restructuring And Related Costs [Table]
Restructuring Cost [Table]
Accrual For Environmental Loss Contingencies Undiscounted One To Five Year
Accrual for environmental loss contingencies undiscounted one to five year.
2027 - 2031
Restructuring and other charges, net (D)
Restructuring and other charges, net
Restructuring and other charges, net (D)
Restructuring And Other Charges
Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Includes expenses related to certain asset retirement obligations.
Income Taxes [Line Items]
Income Taxes [Line Items]
Income taxes.
Recognized net actuarial loss
Defined Benefit Plan, Amortization of Gain (Loss)
Deferred income taxes
Deferred Income Tax Expense (Benefit), Total
Deferred Income Tax Expense (Benefit)
Brazilian Federal Revenue Office [Member]
Brazilian Federal Revenue Office [Member]
Brazilian Federal Revenue Office.
Derivative Forward Energy Volume
Derivative forward energy volume
Derivative forward energy volume.
Business Combination [Abstract]
Diluted
Earnings Per Share, Diluted
Earnings Per Share, Diluted, Total
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Schedule of Operating Results, Capital Expenditures and Assets of Alcoa's Reportable Segments
Operating Segments [Member]
Operating Segments [Member]
Increase (Decrease) in Accounts Payable, Trade
Decrease in accounts payable, trade
Derivative forward energy price
Derivative Forward Energy Price
Derivative forward energy price.
Dividends paid on Alcoa common stock ($0.10 per share)
Dividends, Common Stock, Total
Dividends, Common Stock
City Area Code
City Area Code
Other comprehensive income (loss) (G)
Other Comprehensive Income (Loss), Net of Tax, Total
Other Comprehensive Income (Loss), Net of Tax
Total Other comprehensive income (loss), net of tax
Current restricted cash
Restricted Cash and Cash Equivalent, Current
Restricted Cash and Cash Equivalents, Current, Total
Hillside Aluminum Smelter [Member]
Hillside Aluminum Smelter
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]
Debt Instrument, Face Amount
Principal amount of debt
Unsecured revolving credit facility
Line of Credit Facility, Maximum Borrowing Capacity
Bank guarantees totaling
Schedule Of Defined Benefit Plans Disclosures [Table]
Defined Benefit Plan [Table]
Income Loss From Equity Method Investments Nonoperating
This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied and is reflected as nonoperating income on the Statement of Consolidated Operations.
Equity loss
Disallowed tax credits
Tax Credit Previously Claimed And Disallowed By Tax Authority
Tax credit previously claimed and disallowed by tax authority.
Total amount reclassified from Accumulated other comprehensive loss, net of tax
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]
Segment Reporting Information [Line Items]
Segment Reporting Information [Line Items]
Fair Value Net Derivative Asset Liability Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Supplier invoices outstanding
Supplier Invoices Outstanding
Supplier Invoices Outstanding.
Defined benefit plan remeasurement date.
Defined Benefit Plan Remeasurement Date
Plan remeasurement date
Retirement Plan Name [Axis]
Nonoperating Income (Expense) [Member]
Other Expenses, Net [Member]
Other Income, Net [Member]
Derivative Liabilities Current
Total liability derivatives
Fair value of derivative instruments (L)
Properties, plants, and equipment, net
Property, Plant and Equipment, Net
Brazil [Member]
BRAZIL
Acquisitions, Divestitures, and Joint Ventures [Text Block]
Acquisitions, Divestitures, and Joint Ventures.
Acquisitions, Divestitures, and Joint Ventures
Retained Earnings [Member]
Retained (Deficit) Earnings [Member]
San Ciprian Operations [Member]
San ciprian operations.
San Ciprian Operations [Member]
Net amount reclassified to earnings
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax
Realized gain (loss) reclassified from Accumulated other comprehensive loss to earnings
Share-Based Payment Arrangement, Noncash Expense, Total
Stock-based compensation
Share-Based Payment Arrangement, Noncash Expense
Sale Of Ownership Interest Under Agreement Exchange For Issuance Shares Value
Sale of ownership interest under agreement exchange for issuance shares value.
Sale of ownership interest under agreement exchange for issuance shares value
Long-Term Debt and Lease Obligation
Long-Term Debt and Lease Obligation, Total
Long-term debt, less amount due within one year (J & L)
Fair Value, Inputs, Level 1 [Member]
Level 1 [Member]
Cash Provided by (Used in) Financing Activity, Including Discontinued Operation
CASH (USED FOR) PROVIDED FROM FINANCING ACTIVITIES
Extinguishment of Debt, Type [Domain]
Derivative Liabilities Noncurrent
Total liability derivatives
Fair value of derivative instruments (L)
Minority Interest [Member]
Minority interest.
Non-controlling Interest [Member]
Derivative Contract
Derivative Contract [Domain]
Accrued environmental reserves
Total
Beginning balance
Ending balance
Accrual for Environmental Loss Contingencies
Other Income Expenses [Member]
Other income expenses.
Other Income, Net [Member]
Income Tax Authority
Income Tax Jurisdiction [Domain]
Entity Interactive Data Current
Entity Interactive Data Current
Income Statement Location
Statement of Income Location, Balance [Domain]
Fair Value Measurement
Fair Value Measurement [Domain]
CASH FROM OPERATIONS
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]
Accounting Standards Update and Change in Accounting Principle [Text Block]
Recently Adopted and Recently Issued Accounting Guidance
Purchase percentage interest of put option.
Purchase Percentage Interest Of Put Option
Purchase percentage of interest
Business Combination, Consideration Transferred, Equity Interest, Share Issued, Number of Shares
Business acquisition, shares issued
Decrease in noncurrent liabilities
Increase (Decrease) in Other Noncurrent Liabilities
Fair value measurement, Liabilities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings
Unrecognized net actuarial gain/loss and prior service cost/benefit
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment and Tax, Total
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment and Tax
Aluminum Segment [Member]
Aluminum Products Segment [Member]
Aluminum products segment.
Depreciation, depletion, and amortization
Segment Reporting Information Depreciation Depletion And Amortization Expenses
Segment reporting information depreciation depletion and amortization expenses.
Record Noncontrolling Interest
Record noncontrolling interest.
Record noncontrolling interest (C)
Entity Tax Identification Number
Entity Tax Identification Number
EQUITY
Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Share Price
Weighted average price per share
Non-service costs - pension and other postretirement benefits
Pension and Other Postretirement Benefits Cost (Reversal of Cost)
Pension and Other Postretirement Benefits Cost (Reversal of Cost), Total
London Metal Exchange Forward Price for First and Last Month
London metal exchange forward price for first and last month.
LME forward price for first and last month
Mark-to-market loss on noncurrent marketable securities
Marketable Security, Unrealized Gain (Loss)
Market-to-market gain
Mark-to-market losses
Outstanding quantities of derivative instruments
Outstanding Aluminum Derivative Instruments
Outstanding aluminum derivative instruments.
Income Tax Authority, Name
Income Tax Authority, Name [Domain]
Fair value measurement, Assets
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations, Total
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS AND RESTRICTED CASH
Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation
Pension and other postretirement benefits (L)
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Natural Gas Purchases [Member]
Natural gas purchases.
Local Phone Number
Local Phone Number
Saudi Riyals [Member]
SAUDI ARABIA
Gallium Joint Venture [Member]
Gallium Joint Venture.
Accumulated Other Comprehensive Income Loss [Line Items]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net periodic benefit cost
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)
Other current liabilities
Other Liabilities, Current
Total costs and expenses
Costs And Operating Expenses And Nonoperating Income Expenses
The total costs of sales, operating expenses, and nonoperating expenses/income.
Foreign Exchange Swap Undesignated [Member]
Foreign Exchange Swap Undesignated [Member]
Foreign exchange swap undesignated.
Foreign Exchange Swap Member]
Foreign exchange swap.
Foreign Exchange Swap
Prepaid gas transmission contract
Prepaid Gas Transmission Contract
Prepaid Gas Transmission Contract.
Disaggregation Of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Reversals of previously recorded liabilities
Reversals of previously recorded liabilities
Accrual for Environmental Loss Contingencies, Revision in Estimates
Sales
Sales (E)
Revenue from Contract with Customer, Excluding Assessed Tax
Other Costs [Member]
Other Exit Costs [Member]
Other exit costs.
Schedule of Other Noncurrent Assets
Schedule of Other Assets, Noncurrent [Table Text Block]
Class of Stock [Domain]
Class of Stock
Level 1 and 2 Derivative Instruments [Member]
Derivative Instrument Level1 And2 [Member]
Derivative instrument level 1 and 2.
Entity Emerging Growth Company
Entity Emerging Growth Company