Recently Adopted and Recently Issued Accounting Guidance	9 Months Ended
Sep. 30, 2015
Accounting Changes and Error Corrections [Abstract]
Recently Adopted and Recently Issued Accounting Guidance	B. Recently Adopted and Recently Issued Accounting Guidance Adopted On January 1, 2015, Alcoa adopted changes issued by the Financial Accounting Standards Board (FASB) to reporting discontinued operations and disclosures of disposals of components of an entity. These changes require a disposal of a component to meet a higher threshold in order to be reported as a discontinued operation in an entity’s financial statements. The threshold is defined as a strategic shift that has, or will have, a major effect on an entity’s operations and financial results such as a disposal of a major geographical area or a major line of business. Additionally, the following two criteria have been removed from consideration of whether a component meets the requirements for discontinued operations presentation: (i) the operations and cash flows of a disposal component have been or will be eliminated from the ongoing operations of an entity as a result of the disposal transaction, and (ii) an entity will not have any significant continuing involvement in the operations of the disposal component after the disposal transaction. Furthermore, equity method investments now may qualify for discontinued operations presentation. These changes also require expanded disclosures for all disposals of components of an entity, whether or not the threshold for reporting as a discontinued operation is met, related to profit or loss information and/or asset and liability information of the component. The adoption of these changes had no impact on the Consolidated Financial Statements. This guidance will need to be considered in the event Alcoa initiates a disposal of a component. In September 2015, the FASB issued changes to the accounting for measurement-period adjustments related to business combinations. Currently, an acquiring entity is required to retrospectively adjust the balance sheet amounts of the acquiree recognized at the acquisition date with a corresponding adjustment to goodwill during the measurement period, as well as revise comparative information for prior periods presented within financial statements as needed, including revising income effects, such as depreciation and amortization, as a result of changes made to the balance sheet amounts of the acquiree. Such adjustments are required when new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have affected the measurement of the amounts initially recognized or would have resulted in the recognition of additional assets or liabilities. The measurement period is the period after the acquisition date during which the acquirer may adjust the balance sheet amounts recognized for a business combination (generally up to one year from the date of acquisition). The changes eliminate the requirement to make such retrospective adjustments, and, instead require the acquiring entity to record these adjustments in the reporting period they are determined. Additionally, the changes require the acquiring entity to present separately on the face of the income statement or disclose in the notes to the financial statements the portion of the amount recorded in current-period income by line item that would have been recorded in previous reporting periods if the adjustment to the balance sheet amounts had been recognized as of the acquisition date. These changes were to become effective for Alcoa on January 1, 2016; however, early adoption is permitted. As such, Alcoa elected to early adopt these changes upon issuance and applied the new requirements to two acquisitions (Firth Rixson and TITAL – see Note E) that are in the midst of their respective measurement period. At September 30, 2015, Alcoa recognized adjustments to the original balance sheet amounts of these two acquisitions, resulting in the recognition of amounts in current period income that would have been recorded in previous reporting periods had the adjustments to the balance sheet amounts been recognized as of the respective acquisition date. Such amounts recorded in current period income were not material to the Statement of Consolidated Operations for the third quarter and nine months ended September 30, 2015. Issued In January 2015, the FASB issued changes to the presentation of extraordinary items. Such items are defined as transactions or events that are both unusual in nature and infrequent in occurrence, and, currently, are required to be presented separately in an entity’s income statement, net of income tax, after income from continuing operations. The changes eliminate the concept of an extraordinary item and, therefore, the presentation of such items will no longer be required. Notwithstanding this change, an entity will still be required to present and disclose a transaction or event that is both unusual in nature and infrequent in occurrence in the notes to the financial statements. These changes become effective for Alcoa on January 1, 2016. Management has determined that the adoption of these changes will not have an impact on the Consolidated Financial Statements. In February 2015, the FASB issued changes to the analysis that an entity must perform to determine whether it should consolidate certain types of legal entities. These changes (i) modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities or voting interest entities, (ii) eliminate the presumption that a general partner should consolidate a limited partnership, (iii) affect the consolidation analysis of reporting entities that are involved with variable interest entities, particularly those that have fee arrangements and related party relationships, and (iv) provide a scope exception from consolidation guidance for reporting entities with interests in legal entities that are required to comply with or operate in accordance with requirements that are similar to those in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds. These changes become effective for Alcoa on January 1, 2016. Management is currently evaluating the potential impact of these changes on the Consolidated Financial Statements. In April 2015, the FASB issued changes to the presentation of debt issuance costs. Currently, such costs are required to be presented as a noncurrent asset in an entity’s balance sheet and amortized into interest expense over the term of the related debt instrument. The changes require that debt issuance costs be presented in an entity’s balance sheet as a direct deduction from the carrying value of the related debt liability. The amortization of debt issuance costs remains unchanged. These changes become effective for Alcoa on January 1, 2016. In August 2015, the FASB issued an update to these changes based on an announcement of the staff of the U.S. Securities and Exchange Commission. This change provides an exception to the April 2015 FASB changes allowing debt issuance costs related to line-of-credit arrangements to continue to be presented as an asset regardless of whether there are any outstanding borrowings under such arrangement. This additional change also becomes effective for Alcoa on January 1, 2016. Management has determined that the adoption of all of these changes will result in a decrease of approximately $60 to both Other noncurrent assets and Long-term debt, less amount due within one year on the accompanying Consolidated Balance Sheet. In July 2015, the FASB issued changes to the subsequent measurement of inventory. Currently, an entity is required to measure its inventory at the lower of cost or market, whereby market can be replacement cost, net realizable value, or net realizable value less an approximately normal profit margin. The changes require that inventory be measured at the lower of cost and net realizable value, thereby eliminating the use of the other two market methodologies. Net realizable value is defined as the estimated selling prices in the ordinary course of business less reasonably predictable costs of completion, disposal, and transportation. These changes do not apply to inventories measured using LIFO (last-in, first-out) or the retail inventory method. Currently, Alcoa applies the net realizable value market option to measure non-LIFO inventories at the lower of cost or market. These changes become effective for Alcoa on January 1, 2017. Management has determined that the adoption of these changes will not have an impact on the Consolidated Financial Statements.

B. Recently Adopted and Recently Issued Accounting Guidance

Adopted

On January 1, 2015, Alcoa adopted changes issued by the Financial Accounting Standards Board (FASB) to reporting discontinued operations and disclosures of disposals of components of an entity. These changes require a disposal of a component to meet a higher threshold in order to be reported as a discontinued operation in an entity’s financial statements. The threshold is defined as a strategic shift that has, or will have, a major effect on an entity’s operations and financial results such as a disposal of a major geographical area or a major line of business. Additionally, the following two criteria have been removed from consideration of whether a component meets the requirements for discontinued operations presentation: (i) the operations and cash flows of a disposal component have been or will be eliminated from the ongoing operations of an entity as a result of the disposal transaction, and (ii) an entity will not have any significant continuing involvement in the operations of the disposal component after the disposal transaction. Furthermore, equity method investments now may qualify for discontinued operations presentation. These changes also require expanded disclosures for all disposals of components of an entity, whether or not the threshold for reporting as a discontinued operation is met, related to profit or loss information and/or asset and liability information of the component. The adoption of these changes had no impact on the Consolidated Financial Statements. This guidance will need to be considered in the event Alcoa initiates a disposal of a component.

In September 2015, the FASB issued changes to the accounting for measurement-period adjustments related to business combinations. Currently, an acquiring entity is required to retrospectively adjust the balance sheet amounts of the acquiree recognized at the acquisition date with a corresponding adjustment to goodwill during the measurement period, as well as revise comparative information for prior periods presented within financial statements as needed, including revising income effects, such as depreciation and amortization, as a result of changes made to the balance sheet amounts of the acquiree. Such adjustments are required when new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have affected the measurement of the amounts initially recognized or would have resulted in the recognition of additional assets or liabilities. The measurement period is the period after the acquisition date during which the acquirer may adjust the balance sheet amounts recognized for a business combination (generally up to one year from the date of acquisition). The changes eliminate the requirement to make such retrospective adjustments, and, instead require the acquiring entity to record these adjustments in the reporting period they are determined. Additionally, the changes require the acquiring entity to present separately on the face of the income statement or disclose in the notes to the financial statements the portion of the amount recorded in current-period income by line item that would have been recorded in previous reporting periods if the adjustment to the balance sheet amounts had been recognized as of the acquisition date. These changes were to become effective for Alcoa on January 1, 2016; however, early adoption is permitted. As such, Alcoa elected to early adopt these changes upon issuance and applied the new requirements to two acquisitions (Firth Rixson and TITAL – see Note E) that are in the midst of their respective measurement period. At September 30, 2015, Alcoa recognized adjustments to the original balance sheet amounts of these two acquisitions, resulting in the recognition of amounts in current period income that would have been recorded in previous reporting periods had the adjustments to the balance sheet amounts been recognized as of the respective acquisition date. Such amounts recorded in current period income were not material to the Statement of Consolidated Operations for the third quarter and nine months ended September 30, 2015.

Issued

In January 2015, the FASB issued changes to the presentation of extraordinary items. Such items are defined as transactions or events that are both unusual in nature and infrequent in occurrence, and, currently, are required to be presented separately in an entity’s income statement, net of income tax, after income from continuing operations. The changes eliminate the concept of an extraordinary item and, therefore, the presentation of such items will no longer be required. Notwithstanding this change, an entity will still be required to present and disclose a transaction or event that is both unusual in nature and infrequent in occurrence in the notes to the financial statements. These changes become effective for Alcoa on January 1, 2016. Management has determined that the adoption of these changes will not have an impact on the Consolidated Financial Statements.

In February 2015, the FASB issued changes to the analysis that an entity must perform to determine whether it should consolidate certain types of legal entities. These changes (i) modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities or voting interest entities, (ii) eliminate the presumption that a general partner should consolidate a limited partnership, (iii) affect the consolidation analysis of reporting entities that are involved with variable interest entities, particularly those that have fee arrangements and related party relationships, and (iv) provide a scope exception from consolidation guidance for reporting entities with interests in legal entities that are required to comply with or operate in accordance with requirements that are similar to those in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds. These changes become effective for Alcoa on January 1, 2016. Management is currently evaluating the potential impact of these changes on the Consolidated Financial Statements.

In April 2015, the FASB issued changes to the presentation of debt issuance costs. Currently, such costs are required to be presented as a noncurrent asset in an entity’s balance sheet and amortized into interest expense over the term of the related debt instrument. The changes require that debt issuance costs be presented in an entity’s balance sheet as a direct deduction from the carrying value of the related debt liability. The amortization of debt issuance costs remains unchanged. These changes become effective for Alcoa on January 1, 2016. In August 2015, the FASB issued an update to these changes based on an announcement of the staff of the U.S. Securities and Exchange Commission. This change provides an exception to the April 2015 FASB changes allowing debt issuance costs related to line-of-credit arrangements to continue to be presented as an asset regardless of whether there are any outstanding borrowings under such arrangement. This additional change also becomes effective for Alcoa on January 1, 2016. Management has determined that the adoption of all of these changes will result in a decrease of approximately $60 to both Other noncurrent assets and Long-term debt, less amount due within one year on the accompanying Consolidated Balance Sheet.

In July 2015, the FASB issued changes to the subsequent measurement of inventory. Currently, an entity is required to measure its inventory at the lower of cost or market, whereby market can be replacement cost, net realizable value, or net realizable value less an approximately normal profit margin. The changes require that inventory be measured at the lower of cost and net realizable value, thereby eliminating the use of the other two market methodologies. Net realizable value is defined as the estimated selling prices in the ordinary course of business less reasonably predictable costs of completion, disposal, and transportation. These changes do not apply to inventories measured using LIFO (last-in, first-out) or the retail inventory method. Currently, Alcoa applies the net realizable value market option to measure non-LIFO inventories at the lower of cost or market. These changes become effective for Alcoa on January 1, 2017. Management has determined that the adoption of these changes will not have an impact on the Consolidated Financial Statements.