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Minimum Required Terms of Leases on Cast House Building and Equipment

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Number of employees.

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Period of Operationalizing Rolling Mill Equipment of Transaction Closing Date

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Period of Services Performed, Processing of Metal

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Period of Supply with Aluminum

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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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Total remaining unamortized or unaccreted amounts of premiums, discounts, and intangible assets, in years subsequent to the year of acquisition, when the total amounts of remaining discounts, premiums, and intangible assets exceed 30 percent of stockholders' equity.

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Amount of asset recognized arising from contingent consideration in a business combination.

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Amount of gain on the sale of property that does not qualify for gain recognition as of the balance sheet date.

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- Definition

Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

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- Definition

Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation.

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- Definition

Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Acquisitions and Divestitures - 2018 Divestitures (Details) $ in Millions				3 Months Ended		12 Months Ended
	Dec. 31, 2018 USD ($) employee	Oct. 31, 2018 USD ($)	Apr. 02, 2018 USD ($) employee	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Restructuring and other charges						$ 9	$ 165	$ 155
Gain (loss) on disposition of business						109	(57)	(3)
Latin America Extrusions (LAE)
Business Acquisition [Line Items]
Balance sheet adjustment	$ 2			$ 2		2
Number of employees \| employee			612
Consideration			$ 2
Texarkana, Texas Rolling Mill And Cast House
Business Acquisition [Line Items]
Period of operationalizing rolling mill equipment of transaction closing date		36 months
Minimum required terms of leases on cast house building and equipment		18 months
Period of supply with aluminum		24 months
Gain (loss) on disposition of business		$ 154
Contingent consideration	5			5		5
Deferred gain on sale of property	$ 95			95		95
Eger
Business Acquisition [Line Items]
Number of employees \| employee	180
Consideration	$ 2			2		2
Gain (loss) on disposition of business				$ (43)		(43)
Disposed of by Sale \| Texarkana, Texas Rolling Mill And Cast House
Business Acquisition [Line Items]
Proceeds from divestiture of businesses		63
Consideration		302
Additional contingent consideration		$ 50
Divested Businesses \| Disposed of by Sale \| Latin America Extrusions (LAE)
Business Acquisition [Line Items]
Restructuring and other charges					$ 41
Transportation and Construction Solutions \| Latin America Extrusions (LAE)
Business Acquisition [Line Items]
Sales						25	115	103
Building and Construction Systems \| Third-Party Sales
Business Acquisition [Line Items]
Sales						1,140	1,070	1,010
Engineered Products and Solutions \| Eger
Business Acquisition [Line Items]
Sales						$ 32	$ 38	$ 29
Ta Chen International, Inc. \| Texarkana, Texas Rolling Mill And Cast House
Business Acquisition [Line Items]
Period of services performed, processing of metal		6 years