Alcoa Corp. engages in the production of bauxite, alumina and aluminum products. It operates through the following segments: Bauxite, Alumina, Aluminum, Cast Products, Energy and Rolled Products. The Bauxite segment portfolio represents its bauxite mining assets and it is mined and sold primarily to internal customers within the Alumina segment, who then process it into alumina. The Alumina segment represents its worldwide refining system, which processes bauxite into alumina, which is mainly sold directly to internal and external smelter customers worldwide. The Aluminum segment represents its worldwide smelter system, which receives alumina, mostly from the Alumina segment, and produces molten primary aluminum. The Cast Products segment represents its worldwide cast house system, which are made from molten aluminum, purchased primarily from its Aluminum segment, which is then formed into various value-added ingot products, including billet and slab, for use in fabrication operations