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Preferred and Common Stock - Schedule of Unrecognized Compensation Expense (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2013
Equity [Abstract] |
2014 | $ 36
2015 | 18
2016 | 1
Totals | $ 55

X
- Definition Share based compensation, unrecognized compensation expense expected to be recognized in year one. + References No definition available. + Details
Name: | aa_ShareBasedCompensationUnrecognizedCompensationExpenseExpectedToBeRecognizedInYearOne
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Share based compensation, unrecognized compensation expense expected to be recognized in year three. + References No definition available. + Details
Name: | aa_ShareBasedCompensationUnrecognizedCompensationExpenseExpectedToBeRecognizedInYearThree
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Share based compensation, unrecognized compensation expense expected to be recognized in year two. + References No definition available. + Details
Name: | aa_ShareBasedCompensationUnrecognizedCompensationExpenseExpectedToBeRecognizedInYearTwo
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Share based compensation, unrecognized compensation expense expected to be recognized total. + References No definition available. + Details
Name: | aa_ShareBasedCompensationUnrecognizedCompensationExpenseExpectedToBeRecognizedTotal
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_EquityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration