XML 1034 R121.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 31, 2013 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
Income Taxes [Line Items] |  |  |  |  |
Tax benefit included in discontinued operations |  |  |  | $ 1 |
Tax benefit (charge) realized from exercise of employee stock options |  | (1) | (1) | 6 |
Unamortized tax-deductible goodwill resulting from intercompany stock sales and reorganizations |  | 35 |  |  |
Unamortized tax-deduction rate on goodwill |  | 30.00% |  |  |
Percentage of temporary tax differences that reverse within the carryforward period |  | 30.00% |  |  |
Percentage of temporary tax differences that reverse within tax planning strategies |  | 5.00% |  |  |
Percentage of deferred tax asset exclusive of reversing temporary differences |  | 65.00% |  |  |
Discrete income tax charge for valuation allowances | 372 |  |  |  |
Valuation allowance | 1,804 | 1,804 | 1,400 | 1,398 | 1,268
Holiday period, years |  |  |  | 10 years |
Decrease to the net deferred tax asset and noncash charge to earnings |  |  |  | 50 |
Income tax benefit for operational losses related to certain foreign jurisdictions that are excluded from the estimated annual effective tax rate calculation |  | 5,200 |  |  |
Percentage of the effect of unrecognized tax benefit, if recorded |  | (1.00%) | 6.00% | 2.00% |
Interest and penalties recognized |  | 2 | 3 | 2 |
Income related to accrued interest and penalties |  | 12 | 7 | 2 |
Amount accrued for payment of interest and penalties | 11 | 11 | 15 |  |
Spanish Consolidated Tax Group [Member] |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Discrete income tax charge for valuation allowances |  | 372 |  |  |
Valuation allowance | 237 | 237 |  |  |
Foreign Tax Authority [Member] |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Valuation allowance | $ 135 | $ 135 |  |  |
Foreign tax credits carry forward period |  | 10 years |  |  |
Minimum [Member] | Spanish Consolidated Tax Group [Member] |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Deferred tax assets expiry period |  | 2014 |  |  |
Minimum [Member] | Foreign Tax Authority [Member] |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Foreign tax credits expiry period |  | 2016 |  |  |
Maximum [Member] | Spanish Consolidated Tax Group [Member] |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Deferred tax assets expiry period |  | 2030 |  |  |
Maximum [Member] | Foreign Tax Authority [Member] |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |
Foreign tax credits expiry period |  | 2023 |  |  |

X
- Definition Decrease in net deferred tax asset and noncash charge to earnings. + References No definition available. + Details
Name: | aa_DecreaseInNetDeferredTaxAssetAndNoncashChargeToEarnings
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Deferred tax assets expiry year. + References No definition available. + Details
Name: | aa_DeferredTaxAssetsExpiryYear
Namespace Prefix: | aa_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Discrete Income Tax Expense + References No definition available. + Details
Name: | aa_DiscreteIncomeTaxExpense
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Foreign tax credit carry forwards expiring year. + References No definition available. + Details
Name: | aa_ForeignTaxCreditCarryForwardsExpiringYear
Namespace Prefix: | aa_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Foreign tax credits carryforward period. + References No definition available. + Details
Name: | aa_ForeignTaxCreditsCarryforwardPeriod
Namespace Prefix: | aa_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | aa_IncomeTaxesLineItems
Namespace Prefix: | aa_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Income tax expense, payment of interest and penalties. + References No definition available. + Details
Name: | aa_IncomeTaxExpensePaymentOfInterestAndPenalties
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Income tax holiday, holiday period. + References No definition available. + Details
Name: | aa_IncomeTaxHolidayHolidayPeriod
Namespace Prefix: | aa_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of deferred tax asset exclusive of reversing temporary differences. + References No definition available. + Details
Name: | aa_PercentageOfDeferredTaxAssetExclusiveOfReversingTemporaryDifferences
Namespace Prefix: | aa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of the effect of unrecognized tax benefit, if recorded. + References No definition available. + Details
Name: | aa_PercentageOfEffectOfUnrecognizedTaxBenefitIfRecorded
Namespace Prefix: | aa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of temporary tax differences that reverse within the carryforward period. + References No definition available. + Details
Name: | aa_PercentageOfTemporaryTaxDifferencesThatReverseWithinCarryforwardPeriod
Namespace Prefix: | aa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of temporary tax differences that reverse within tax planning strategies. + References No definition available. + Details
Name: | aa_PercentageOfTemporaryTaxDifferencesThatReverseWithinTaxPlanningStrategies
Namespace Prefix: | aa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unamortized tax deductible goodwill resulting from intercompany stock sales and reorganizations. + References No definition available. + Details
Name: | aa_UnamortizedTaxDeductibleGoodwillResultingFromIntercompanyStockSalesAndReorganizations
Namespace Prefix: | aa_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Unamortized tax deduction rate on goodwill. + References No definition available. + Details
Name: | aa_UnamortizedTaxDeductionRateOnGoodwill
Namespace Prefix: | aa_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319 + Details
Name: | us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tax benefit from provision recognizing a loss for initial, or subsequent, write-down to fair value (less cost to sell) of a of a disposal group that is classified as a component of the entity, which remains unsold as of the reporting date. May include a tax on the (gain) for the recognition of a subsequent increase in fair value (less cost to sell), but not in excess of the cumulative loss previously recognized through write-downs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=18498875&loc=d3e38679-109324 + Details
Name: | us-gaap_DiscontinuedOperationTaxExpenseBenefitFromProvisionForGainLossOnDisposal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
Name: | us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in foreign income tax contingency. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319 + Details
Name: | us-gaap_IncomeTaxReconciliationTaxContingenciesForeign
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of statutory penalties accrued for a tax position claimed or expected to be claimed by the entity, in its tax return. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant