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Segment Information - Schedule of Segment ATOI to Consolidated Net Income Attributable to Alcoa (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2016 | Jun. 30, 2015
Segment Reporting Information [Line Items] |  |  |  |
Total segment ATOI | $ 444 | $ 567 | $ 735 | $ 1,223
Metal price lag | 7 | (39) | 8 | (62)
Interest expense | (129) | (124) | (256) | (246)
Noncontrolling interests | (43) | (67) | (38) | (127)
Consolidated net income attributable to Alcoa | 135 | 140 | 151 | 335
Other [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Impact of LIFO | (10) | 36 | (6) | 43
Interest expense | (84) | (80) | (167) | (160)
Noncontrolling interests | (43) | (67) | (38) | (127)
Corporate expense | (77) | (65) | (132) | (127)
Restructuring and other charges | (15) | (159) | (76) | (320)
Other | $ (87) | $ (53) | $ (173) | $ (135)

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