Other Financial Information - Schedule of Other Noncurrent Liabilities and Deferred Credits (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Other Financial Information [Abstract]
Accrued compensation and retirement costs	$ 107	$ 127
Deferred alumina sales revenue	61	68
Other	54	84
Other noncurrent liabilities and deferred credits, total	$ 222	$ 279

Other Financial Information [Abstract]

No definition available.

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- Definition

Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

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Carrying amount as of the balance sheet date of unearned revenue or income, not otherwise specified in the taxonomy, which is expected to be taken into income after one year or beyond the normal operating cycle, if longer and noncurrent obligations not separately disclosed in the balance sheet (other liabilities, noncurrent).

+ References

No definition available.

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- Definition

The noncurrent portion of deferred revenue amount as of balance sheet date. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized, and is not expected to be recognized in the next twelve months. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

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Obligations not otherwise itemized or categorized in the footnotes to the financial statements that are expected to be paid after one year (or the normal operating cycle, if longer), from the balance sheet date.

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