XML 1154 R154.htm IDEA: XBRL DOCUMENT v2.4.0.8
Derivatives and Other Financial Instruments - Schedule of Quantitative Information for Level 3 Derivative Contracts (Detail) (USD $)
 12 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Sep. 30, 2012
Dec. 31, 2013
Interrelationship of Future Aluminum and Oil Prices [Member]
Aluminum Contracts [Member]
Dec. 31, 2013
Interrelationship of Future Aluminum and Oil Prices [Member]
Aluminum Contracts [Member]
Minimum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Interrelationship of Future Aluminum and Oil Prices [Member]
Aluminum Contracts [Member]
Maximum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Interrelationship of Future Aluminum Prices, Foreign Currency Exchange Rates, and U.S. Consumer Price Index [Member]
Aluminum Contracts [Member]
Dec. 31, 2013
Interrelationship of Future Aluminum Prices, Foreign Currency Exchange Rates, and U.S. Consumer Price Index [Member]
Aluminum Contracts [Member]
Minimum [Member]
Discounted Cash Flow [Member]
Index
Dec. 31, 2013
Interrelationship of Future Aluminum Prices, Foreign Currency Exchange Rates, and U.S. Consumer Price Index [Member]
Aluminum Contracts [Member]
Maximum [Member]
Discounted Cash Flow [Member]
Index
Dec. 31, 2013
Interrelationship of LME Price to Overall Energy Price [Member]
Aluminum Contracts [Member]
Dec. 31, 2013
Interrelationship of LME Price to Overall Energy Price [Member]
Aluminum Contracts [Member]
Minimum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Interrelationship of LME Price to Overall Energy Price [Member]
Aluminum Contracts [Member]
Maximum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Price of Electricity Beyond Forward Curve [Member]
Energy Contracts [Member]
Dec. 31, 2013
Price of Electricity Beyond Forward Curve [Member]
Energy Contracts [Member]
Minimum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Price of Electricity Beyond Forward Curve [Member]
Energy Contracts [Member]
Maximum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Price of Aluminum Beyond Forward Curve [Member]
Aluminum Contracts [Member]
Dec. 31, 2013
Price of Aluminum Beyond Forward Curve [Member]
Aluminum Contracts [Member]
Minimum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Price of Aluminum Beyond Forward Curve [Member]
Aluminum Contracts [Member]
Maximum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Credit Spread Between Alcoa and Counterparty [Member]
Embedded Credit Derivative [Member]
Dec. 31, 2013
Credit Spread Between Alcoa and Counterparty [Member]
Embedded Credit Derivative [Member]
Minimum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Credit Spread Between Alcoa and Counterparty [Member]
Embedded Credit Derivative [Member]
Maximum [Member]
Discounted Cash Flow [Member]
Dec. 31, 2013
Credit Spread Between Alcoa and Counterparty [Member]
Embedded Credit Derivative [Member]
Median [Member]
Discounted Cash Flow [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]                                            
Derivative Assets, Fair value $ 390,000,000 $ 596,000,000 $ 596,000,000        $ 324,000,000     $ 25,000,000     $ 6,000,000                  
Price of aluminum beyond forward curve                                 2,485 2,647        
Derivative Liabilities, Fair value 479,000,000 679,000,000                           410,000,000     21,000,000      
Expected future aluminum prices         1,774 2,221   1,784 2,064   1,839 2,239                    
Maturity year of future aluminum price         2014 2018   2014 2016   2014 2019         2023 2027        
Expected future oil prices         89 112                                
Percentage of credit spread                                       0.98% 1.66% 1.32%
Price of electricity beyond forward curve                           $ 82 $ 154              
Maturity year of future oil price         2018 2014                                
Maturity date of electricity beyond forward curve                           2014 2036              
Foreign currency exchange rate               1                            
Foreign currency exchange rate               0.89 0.83                          
Foreign currency exchange rate expected year               2014 2016                          
Consumer price index base year                 1982                          
Expected consumer price index               231 246                          
Consumer price index base                 100                          
Expected consumer price index, Year               2014 2016