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Income tax examination assessment outstanding.

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Letters Of Credit, Total

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Number of cleanup locations.

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Percentage of cost of goods sold.

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Separation And Distribution Agreement, Surety Bonds, Amount Outstanding

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Tax Agreement, Indemnification of Ultimate Liability, Percent

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- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

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Amount of cash outflow to settle environmental loss contingencies.

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Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable in twelve months or in the next operating cycle if longer.

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The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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Fair value portion of guarantee, including, but not limited to, financial standby letter of credit, fair value guarantee, guarantee of collection of scheduled contractual cash flows from financial assets, and contracts that contingently require the guarantor to make payments or perform services.

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Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.

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The change in the reserve for commissions, expenses and taxes recorded on the balance sheet, which is needed to adjust net income to arrive at net cash flows provided by or used in operations.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of plaintiffs that have filed claims pertaining to a loss contingency.

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Contingencies and Commitments (Details) € in Millions, $ in Millions		3 Months Ended		6 Months Ended
	Jun. 06, 2019 plaintiff	Jun. 30, 2020 USD ($)	Jun. 30, 2020 EUR (€)	Jun. 30, 2020 USD ($) location	Jun. 30, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2018	Nov. 01, 2016 USD ($)
Loss Contingencies [Line Items]
Number of cleanup locations \| location				30
Remediation reserve balance						$ 8	$ 8
Remediation reserve balance, classified as a current liability						3	$ 4
Payments related to remediation expenses applied against the reserve		$ 1
Income tax examination assessment outstanding		174		$ 174	€ 154
Income tax reserve		60	€ 54
Tax indemnification receivable		50		50	€ 45
Number of plaintiffs \| plaintiff	247
Guarantees of third party related to project financing		25		25
Combined fair value of guarantees		16		16		9
Total amount committed under outstanding surety bonds		43		43
Surety bonds, amount outstanding		26		26
Bank Loan Obligations
Loss Contingencies [Line Items]
Letters of credit, total amount		66		66
Other Noncurrent Liabilities and Deferred Credits \| Separation Agreement
Loss Contingencies [Line Items]
Guarantees of third party related to project financing		$ 1,167		$ 1,167		$ 1,353
Alcoa Corporation
Loss Contingencies [Line Items]
Tax agreement, indemnification of ultimate liability (percent)		49.00%		49.00%	49.00%			49.00%
Arconic Corporation
Loss Contingencies [Line Items]
Tax agreement, indemnification of ultimate liability (percent)		34.00%		34.00%	34.00%
Howmet Aerospace
Loss Contingencies [Line Items]
Tax agreement, indemnification of ultimate liability (percent)		17.00%		17.00%	17.00%
Recurring Costs of Managing Hazardous Substances and Environmental Programs \| Maximum
Loss Contingencies [Line Items]
Percentage of cost of goods sold (percent)				1.00%
Alcoa Corporation Workers Compensation Claims
Loss Contingencies [Line Items]
Letters of credit, total amount outstanding									$ 54