Acquisitions and Divestitures	3 Months Ended
Mar. 31, 2016
Business Combinations [Abstract]
Acquisitions and Divestitures	E. Acquisitions and Divestitures – In March 2015, Alcoa completed the acquisition of an aerospace structural castings company, TITAL, for $205 (€189) in cash. Alcoa recognized goodwill of $117 for this transaction, none of which is deductible for income tax purposes. The purchase price allocation has been finalized. In July 2015, Alcoa completed the acquisition of RTI International Metals, Inc. (RTI). RTI was a global supplier of titanium and specialty metal products and services for the commercial aerospace, defense, energy, and medical device end markets. The purpose of this acquisition was to expand Alcoa’s range of titanium offerings and add advanced technologies and materials, primarily related to the aerospace end market. Alcoa purchased all outstanding shares of RTI common stock in a stock-for-stock transaction valued at $870 (based on the $9.96 per share July 23, 2015 closing price of Alcoa’s common stock). Each issued and outstanding share of RTI common stock prior to the completion of the transaction was converted into the right to receive 2.8315 shares of Alcoa common stock. In total, Alcoa issued 87,397,414 shares of its common stock to consummate this transaction. The operating results and assets and liabilities of RTI were included within Alcoa’s Engineered Products and Solutions segment since the date of acquisition. Based on the preliminary allocation of the purchase price, goodwill of $251 was recorded for this transaction, none of which is estimated to be deductible for income tax purposes. The final allocation of the purchase price will be based on management’s best estimates, including a third-party valuation of the assets acquired and other studies related to potential environmental and contingent liabilities. In March 2016, Alcoa reached an agreement for the sale of its Remmele Medical business for $102 in cash, subject to post-closing adjustments (this transaction closed on April 29, 2016). This business, which was acquired by Alcoa in July 2015 in conjunction with the RTI acquisition, generated sales of approximately $16 in the first quarter of 2016. The operating results and assets and liabilities of the business were included in the Engineered Products and Solutions segment. Also in March 2016, Alcoa’s majority-owned subsidiary, Alcoa of Australia Limited (AofA), which is part of Alcoa World Alumina and Chemicals (AWAC), reached an agreement to sell its 20% interest in DBP, the owner and operator of the Dampier to Bunbury Natural Gas Pipeline (DBNGP) for $154 (A$205) in cash. As part of the transaction, AofA will maintain its current access to approximately 30% of the DBNGP transmission capacity for gas supply to its three alumina refineries in Western Australia. See Note G for additional information. Additionally in March 2016, Alcoa sold certain company-owned life insurance contracts for $234 in cash. No gain or loss was recognized on the sale of these contracts. These contracts were included in Other noncurrent assets on the accompanying Consolidated Balance Sheet at December 31, 2015. In the first quarter of 2015, Alcoa completed the divestiture of an operation in Russia (see below) and had post-closing adjustments, as provided for in the respective purchase agreements, related to three divestitures completed in December 2014. The divestiture and post-closing adjustments combined resulted in a net cash payment of $8 and a net loss of $149 ($142 after-tax and noncontrolling interest), which was recorded in Restructuring and other charges (see Note D) on the accompanying Statement of Consolidated Operations. These four divestitures are no longer subject to post-closing adjustments. In March 2015, Alcoa completed the sale of a rolling mill located in Belaya Kalitva, Russia to a wholly-owned subsidiary of Stupino Titanium Company. While owned by Alcoa, the operating results and assets and liabilities of the rolling mill were included in the Global Rolled Products segment.

E. Acquisitions and Divestitures – In March 2015, Alcoa completed the acquisition of an aerospace structural castings company, TITAL, for $205 (€189) in cash. Alcoa recognized goodwill of $117 for this transaction, none of which is deductible for income tax purposes. The purchase price allocation has been finalized.

In July 2015, Alcoa completed the acquisition of RTI International Metals, Inc. (RTI). RTI was a global supplier of titanium and specialty metal products and services for the commercial aerospace, defense, energy, and medical device end markets. The purpose of this acquisition was to expand Alcoa’s range of titanium offerings and add advanced technologies and materials, primarily related to the aerospace end market. Alcoa purchased all outstanding shares of RTI common stock in a stock-for-stock transaction valued at $870 (based on the $9.96 per share July 23, 2015 closing price of Alcoa’s common stock). Each issued and outstanding share of RTI common stock prior to the completion of the transaction was converted into the right to receive 2.8315 shares of Alcoa common stock. In total, Alcoa issued 87,397,414 shares of its common stock to consummate this transaction. The operating results and assets and liabilities of RTI were included within Alcoa’s Engineered Products and Solutions segment since the date of acquisition. Based on the preliminary allocation of the purchase price, goodwill of $251 was recorded for this transaction, none of which is estimated to be deductible for income tax purposes. The final allocation of the purchase price will be based on management’s best estimates, including a third-party valuation of the assets acquired and other studies related to potential environmental and contingent liabilities.

In March 2016, Alcoa reached an agreement for the sale of its Remmele Medical business for $102 in cash, subject to post-closing adjustments (this transaction closed on April 29, 2016). This business, which was acquired by Alcoa in July 2015 in conjunction with the RTI acquisition, generated sales of approximately $16 in the first quarter of 2016. The operating results and assets and liabilities of the business were included in the Engineered Products and Solutions segment.

Also in March 2016, Alcoa’s majority-owned subsidiary, Alcoa of Australia Limited (AofA), which is part of Alcoa World Alumina and Chemicals (AWAC), reached an agreement to sell its 20% interest in DBP, the owner and operator of the Dampier to Bunbury Natural Gas Pipeline (DBNGP) for $154 (A$205) in cash. As part of the transaction, AofA will maintain its current access to approximately 30% of the DBNGP transmission capacity for gas supply to its three alumina refineries in Western Australia. See Note G for additional information.

Additionally in March 2016, Alcoa sold certain company-owned life insurance contracts for $234 in cash. No gain or loss was recognized on the sale of these contracts. These contracts were included in Other noncurrent assets on the accompanying Consolidated Balance Sheet at December 31, 2015.

In the first quarter of 2015, Alcoa completed the divestiture of an operation in Russia (see below) and had post-closing adjustments, as provided for in the respective purchase agreements, related to three divestitures completed in December 2014. The divestiture and post-closing adjustments combined resulted in a net cash payment of $8 and a net loss of $149 ($142 after-tax and noncontrolling interest), which was recorded in Restructuring and other charges (see Note D) on the accompanying Statement of Consolidated Operations. These four divestitures are no longer subject to post-closing adjustments.

In March 2015, Alcoa completed the sale of a rolling mill located in Belaya Kalitva, Russia to a wholly-owned subsidiary of Stupino Titanium Company. While owned by Alcoa, the operating results and assets and liabilities of the rolling mill were included in the Global Rolled Products segment.