Acquisitions and Divestitures	9 Months Ended
Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions and Divestitures	Acquisitions and Divestitures In March 2017, Arconic completed the sale of its Fusina, Italy rolling mill to Slim Aluminium. While owned by Arconic, the operating results and assets and liabilities of the Fusina, Italy rolling mill were included in the Global Rolled Products segment. As part of the transaction, Arconic injected $10 of cash into the business and provided a third-party guarantee with a fair value of $5 related to Slim Aluminium’s environmental remediation. The Company recorded a loss on the sale of $60, which was recorded in Restructuring and other charges (see Note E) on the Statement of Consolidated Operations in the first quarter of 2017. The rolling mill generated third-party sales of approximately $37 in the first quarter of 2017. At the time of the divestiture, the rolling mill had approximately 312 employees. On April 2, 2018, Arconic completed the sale of its Latin America extrusions business to a subsidiary of Hydro Extruded Solutions AS for $5 in cash, subject to post-closing adjustments that are not expected to be significant. The sales price approximates the carrying value of the net assets sold on the closing date, following the charge of $41 recognized in the fourth quarter of 2017 related to the non-cash impairment of the net book value of the business. The operating results and assets and liabilities of the business were included in the Transportation and Construction Solutions segment. This business generated sales of approximately $30 in the third quarter of 2017, and $25 and $86 in the nine months ended September 30, 2018 and 2017, respectively. On July 31, 2018, the Company announced that it had initiated a sale process of its Building and Construction Systems (BCS) business, as part of the Company’s ongoing strategy and portfolio review that commenced in January 2018. BCS is part of the Transportation and Construction Solutions segment and generated third-party sales of approximately $1,070 for the year ended December 31, 2017. The sale process is in its early stages. The Company’s decision regarding whether to sell the business will not be finalized until final binding offers are evaluated at a later stage in the sale process. Until the Company makes that final decision, the BCS business will remain classified as held and in-use in the Consolidated Financial Statements. On October 31, 2018, the Company sold its Texarkana, Texas rolling mill and cast house, which had a combined net book value of $63, to Ta Chen International, Inc. for $302 in cash, subject to post-closing adjustments, plus additional contingent consideration of up to $50. The contingent consideration relates to the achievement of various milestones within 36 months of the transaction closing date associated with operationalizing the rolling mill equipment. The Texarkana rolling mill facility had previously been idle since late 2009. In early 2016, the Company restarted the Texarkana cast house to meet demand for aluminum slab. As part of the agreement, the Company will continue to produce aluminum slab at the facility for a period of 18 months through a lease back of the cast house building and equipment, after which time, Ta Chen will perform toll processing of metal for the Company for a period of six months. The Company will supply Ta Chen with cold-rolled aluminum coil during this 24-month period. The sale of the rolling mill and cast house will be accounted for separately. The gain on the sale of the rolling mill is estimated to be approximately $150 to $165 including the fair value of contingent consideration of $4, which will be recorded in the fourth quarter of 2018. The Company will reevaluate its estimate of the amount of contingent consideration to which it will be entitled at the end of each reporting period and recognize any changes thereto in the Statement of Consolidated Operations. The Company will have continuing involvement related to the cast house, and, therefore will use the failed-sale-leaseback accounting model. Under such model, the Company is deemed to still own the cast house building and equipment sold to Ta Chen, and therefore the Company must continue to reflect these assets in its Consolidated Balance Sheet and depreciate them over the remaining useful life. Additionally, the Company will record the cash proceeds associated with the cast house as a noncurrent liability in its Consolidated Balance Sheet. The Company will defer a gain estimated at approximately $85 to $100 associated with the cast house assets.

Acquisitions and Divestitures

In March 2017, Arconic completed the sale of its Fusina, Italy rolling mill to Slim Aluminium. While owned by Arconic, the operating results and assets and liabilities of the Fusina, Italy rolling mill were included in the Global Rolled Products segment. As part of the transaction, Arconic injected $10 of cash into the business and provided a third-party guarantee with a fair value of $5 related to Slim Aluminium’s environmental remediation. The Company recorded a loss on the sale of $60, which was recorded in Restructuring and other charges (see Note E) on the Statement of Consolidated Operations in the first quarter of 2017. The rolling mill generated third-party sales of approximately $37 in the first quarter of 2017. At the time of the divestiture, the rolling mill had approximately 312 employees.

On April 2, 2018, Arconic completed the sale of its Latin America extrusions business to a subsidiary of Hydro Extruded Solutions AS for $5 in cash, subject to post-closing adjustments that are not expected to be significant. The sales price approximates the carrying value of the net assets sold on the closing date, following the charge of $41 recognized in the fourth quarter of 2017 related to the non-cash impairment of the net book value of the business. The operating results and assets and liabilities of the business were included in the Transportation and Construction Solutions segment. This business generated sales of approximately $30 in the third quarter of 2017, and $25 and $86 in the nine months ended September 30, 2018 and 2017, respectively.

On July 31, 2018, the Company announced that it had initiated a sale process of its Building and Construction Systems (BCS) business, as part of the Company’s ongoing strategy and portfolio review that commenced in January 2018. BCS is part of the Transportation and Construction Solutions segment and generated third-party sales of approximately $1,070 for the year ended December 31, 2017. The sale process is in its early stages. The Company’s decision regarding whether to sell the business will not be finalized until final binding offers are evaluated at a later stage in the sale process. Until the Company makes that final decision, the BCS business will remain classified as held and in-use in the Consolidated Financial Statements.

On October 31, 2018, the Company sold its Texarkana, Texas rolling mill and cast house, which had a combined net book value of $63, to Ta Chen International, Inc. for $302 in cash, subject to post-closing adjustments, plus additional contingent consideration of up to $50. The contingent consideration relates to the achievement of various milestones within 36 months of the transaction closing date associated with operationalizing the rolling mill equipment. The Texarkana rolling mill facility had previously been idle since late 2009. In early 2016, the Company restarted the Texarkana cast house to meet demand for aluminum slab. As part of the agreement, the Company will continue to produce aluminum slab at the facility for a period of 18 months through a lease back of the cast house building and equipment, after which time, Ta Chen will perform toll processing of metal for the Company for a period of six months. The Company will supply Ta Chen with cold-rolled aluminum coil during this 24-month period.

The sale of the rolling mill and cast house will be accounted for separately. The gain on the sale of the rolling mill is estimated to be approximately $150 to $165 including the fair value of contingent consideration of $4, which will be recorded in the fourth quarter of 2018. The Company will reevaluate its estimate of the amount of contingent consideration to which it will be entitled at the end of each reporting period and recognize any changes thereto in the Statement of Consolidated Operations. The Company will have continuing involvement related to the cast house, and, therefore will use the failed-sale-leaseback accounting model. Under such model, the Company is deemed to still own the cast house building and equipment sold to Ta Chen, and therefore the Company must continue to reflect these assets in its Consolidated Balance Sheet and depreciate them over the remaining useful life. Additionally, the Company will record the cash proceeds associated with the cast house as a noncurrent liability in its Consolidated Balance Sheet. The Company will defer a gain estimated at approximately $85 to $100 associated with the cast house assets.