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Investments (Tables) | 6 Months Ended
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Jun. 30, 2016
Investments Schedule [Abstract] |
Summary of Unaudited Financial Information for Alcoa's Equity Investments | A summary of unaudited financial information for Alcoa’s equity investments is as follows (amounts represent 100% of investee financial information):
|  | Second quarter ended June 30, |  |  | Six months ended June 30, |
|  | 2016 |  |  | 2015 |  |  | 2016 |  |  | 2015 |
Sales |  | $ | 904 |  |  | $ | 971 |  |  | $ | 1,796 |  |  | $ | 1,857 |
Cost of goods sold |  |  | 679 |  |  |  | 862 |  |  |  | 1,360 |  |  |  | 1,557 |
Net income (loss) |  |  | 14 |  |  |  | (45 | ) |  |  | 29 |  |  |  | (86 | )

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