Derivatives And Other Financial Instruments (Outstanding Forward Contracts That Were Entered Into Hedge Forward Transactions) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Jun. 30, 2011	Dec. 31, 2010
Aluminum contracts (kmt)	1,194	1,285
Energy Contract [Member]
Electricity (megawatt hours)	100,578,295	100,578,295
Foreign exchange contracts	$ 10	$ 20

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aa_OutstandingForwardContractsEnteredIntoAsHedgeForecastedTransactionsForeignExchangeContracts

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aa

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xbrli:monetaryItemType

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debit

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duration