Other Noncurrent Liabilities and Deferred Credits - Schedule of Other Noncurrent Liabilities and Deferred Credits (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Payables And Accruals [Abstract]
Asset retirement obligations (C)	$ 544	$ 535
Environmental remediation (N)	461	458
Fair value of derivative contracts (X)	420	606
Income taxes (T)	403	460
Accrued compensation and retirement costs	342	322
Liability related to the resolution of a legal matter (N)	296
Deferred credit related to derivative contract (X)	157	330
Deferred alumina sales revenue	101	108
Other	247	259
Other noncurrent liabilities and deferred credits, total	$ 2,971	$ 3,078

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

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Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all domestic and foreign income tax obligations due beyond one year or the operating cycle, whichever is longer. Alternate captions include income taxes payable, noncurrent.

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Carrying amount of estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs, which is expected to be paid after one year or beyond 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.

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