Other Noncurrent Liabilities And Deferred Credits (Schedule Of Other Noncurrent Liabilities And Deferred Credits) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Other Noncurrent Liabilities And Deferred Credits [Abstract]
Fair value of derivative contracts (X)	$ 624	$ 703
Asset retirement obligations (C)	503	442
Deferred income taxes (T)	395	388
Accrued compensation and retirement costs	304	314
Environmental remediation (N)	289	302
Deferred alumina sales revenue	116	125
Other	197	302
Other noncurrent liabilities and deferred credits, total	$ 2,428	$ 2,576

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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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.

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- Definition

Represents the noncurrent portion of deferred tax liabilities, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. A noncurrent taxable temporary difference is a difference between the tax basis and the carrying amount of a noncurrent asset or liability in the financial statements prepared in accordance with generally accepted accounting principles. In a classified statement of financial position, an enterprise separates deferred tax liabilities and assets into a current amount and a noncurrent amount. Deferred tax liabilities and assets are classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, are classified according to the expected reversal date of the temporary difference.

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- Definition

Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be extinguished or otherwise disposed of after one year or beyond the normal operating cycle, if longer, net of the effects of master netting arrangements.

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