Acquisitions and Divestitures	12 Months Ended
Dec. 31, 2021
Business Combinations [Abstract]
Acquisitions and Divestitures	Acquisitions and Divestitures Divestitures Itapissuma. On February 1, 2020, Arconic completed the sale of its aluminum rolling mill (aseptic foil and sheet products) in Itapissuma, Brazil to Companhia Brasileira de Alumínio for a net $46 in cash. In December 2020, the Company paid $4 in cash to Companhia Brasileira de Alumínio to settle certain working capital and other post-closing adjustments. Additionally, in June 2021, the Company paid $2 in cash to Companhia Brasileira de Alumínio to settle the remaining working capital and other post-closing adjustments. Arconic has recognized a cumulative loss of $60 (pretax) on this transaction, composed of the following: a charge of $53 in 2019 for the non-cash impairment of the carrying value (i.e., write-down to fair value) of the rolling mill’s net assets, primarily properties, plants, and equipment, as a result of entering into an agreement in August 2019 to sell this rolling mill; a charge of $6 in February 2020 for further necessary adjustments upon completion of the divestiture; and a charge of $1 in March 2021 for a then-proposed final settlement of the remaining post-closing adjustments and other items. Each of these amounts were recorded in Restructuring and other charges (see Note E) on the accompanying Statement of Consolidated Operations in the respective reporting periods. This transaction is no longer subject to post-closing adjustments. Prior to the divestiture, this rolling mill’s operating results and assets and liabilities were reported in Arconic’s Rolled Products segment. The rolling mill generated third-party sales of $143 in 2019 and, at the time of divestiture, had approximately 500 employees. Changwon. On March 1, 2020, Arconic completed the sale of its hard alloy extrusions plant in South Korea to SeAH Besteel Corporation for a net $55 in cash, resulting in a gain of $31 (pretax), which was recorded in Restructuring and other charges (see Note E) on the accompanying Statement of Consolidated Operations. The gain is net of a $6 write-off of related goodwill. In May 2020, the Company received an additional $1 in cash as a result of a post-closing adjustment, which was previously contemplated in the aforementioned gain. This transaction is no longer subject to post-closing adjustments. Prior to the divestiture, this plant’s operating results and assets and liabilities were reported in Arconic’s Extrusions segment. The extrusions plant generated third-party sales of $51 in 2019 and, at the time of divestiture, had approximately 160 employees. Texarkana. In October 2018, Arconic 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 related to the achievement of various milestones associated with operationalizing the rolling mill equipment within 36 months of the transaction closing date. 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. While owned by Arconic, the operating results and assets and liabilities of the business were included in the Company’s Rolled Products segment. As part of the sale agreement, Arconic continued 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 performed toll processing of metal for the Company for a period of six months. Arconic supplied Ta Chen with cold-rolled aluminum coil during this 24-month period. The sale of the rolling mill and cast house was accounted for separately. In 2018, a gain on the sale of the rolling mill of $154, including fair value of contingent consideration of $5, was recorded in Restructuring and other charges on the Company’s Statement of Consolidated Operations. In 2020 and 2019, Arconic received additional contingent consideration of $25 and $20, respectively, which was recorded as a gain in Restructuring and other charges (see Note E) on the accompanying Statement of Consolidated Operations in the respective reporting periods. As of December 31, 2020, there was no remaining contingent consideration associated with this transaction. The Company had continuing involvement related to the lease back of the cast house. As a result, Arconic continued to recognize as assets, as well as depreciate, the cast house building and equipment that it sold to Ta Chen, and recorded the portion of the cash proceeds associated with the sale of the cast house assets as a noncurrent liability, including a deferred gain of $95. As of December 31, 2018, the Company’s Consolidated Balance Sheet included $24 in Properties, plants, and equipment, net, $22 in Deferred income taxes (noncurrent asset), and $119 in Other noncurrent liabilities and deferred credits. On January 1, 2019, Arconic adopted the lease accounting guidance (see Recently Adopted Accounting Guidance in Note B), under which the Company’s continuing involvement no longer required deferral of the recognition of the sale of the cast house. Accordingly, the carrying value of these assets and liabilities were reclassified to equity reflecting a net $73 cumulative effect of an accounting change on the date of adoption.

Itapissuma. On February 1, 2020, Arconic completed the sale of its aluminum rolling mill (aseptic foil and sheet products) in Itapissuma, Brazil to Companhia Brasileira de Alumínio for a net $46 in cash. In December 2020, the Company paid $4 in cash to Companhia Brasileira de Alumínio to settle certain working capital and other post-closing adjustments. Additionally, in June 2021, the Company paid $2 in cash to Companhia Brasileira de Alumínio to settle the remaining working capital and other post-closing adjustments. Arconic has recognized a cumulative loss of $60 (pretax) on this transaction, composed of the following: a charge of $53 in 2019 for the non-cash impairment of the carrying value (i.e., write-down to fair value) of the rolling mill’s net assets, primarily properties, plants, and equipment, as a result of entering into an agreement in August 2019 to sell this rolling mill; a charge of $6 in February 2020 for further necessary adjustments upon completion of the divestiture; and a charge of $1 in March 2021 for a then-proposed final settlement of the remaining post-closing adjustments and other items. Each of these amounts were recorded in Restructuring and other charges (see Note E) on the accompanying Statement of Consolidated Operations in the respective reporting periods. This transaction is no longer subject to post-closing adjustments. Prior to the divestiture, this rolling mill’s operating results and assets and liabilities were reported in Arconic’s Rolled Products segment. The rolling mill generated third-party sales of $143 in 2019 and, at the time of divestiture, had approximately 500 employees.

Changwon. On March 1, 2020, Arconic completed the sale of its hard alloy extrusions plant in South Korea to SeAH Besteel Corporation for a net $55 in cash, resulting in a gain of $31 (pretax), which was recorded in Restructuring and other charges (see Note E) on the accompanying Statement of Consolidated Operations. The gain is net of a $6 write-off of related goodwill. In May 2020, the Company received an additional $1 in cash as a result of a post-closing adjustment, which was previously contemplated in the aforementioned gain. This transaction is no longer subject to post-closing adjustments. Prior to the divestiture, this plant’s operating results and assets and liabilities were reported in Arconic’s Extrusions segment. The extrusions plant generated third-party sales of $51 in 2019 and, at the time of divestiture, had approximately 160 employees.

Texarkana. In October 2018, Arconic 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 related to the achievement of various milestones associated with operationalizing the rolling mill equipment within 36 months of the transaction closing date. 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. While owned by Arconic, the operating results and assets and liabilities of the business were included in the Company’s Rolled Products segment. As part of the sale agreement, Arconic continued 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 performed toll processing of metal for the Company for a period of six months. Arconic supplied Ta Chen with cold-rolled aluminum coil during this 24-month period.

The sale of the rolling mill and cast house was accounted for separately. In 2018, a gain on the sale of the rolling mill of $154, including fair value of contingent consideration of $5, was recorded in Restructuring and other charges on the Company’s Statement of Consolidated Operations. In 2020 and 2019, Arconic received additional contingent consideration of $25 and $20, respectively, which was recorded as a gain in Restructuring and other charges (see Note E) on the accompanying Statement of Consolidated Operations in the respective reporting periods. As of December 31, 2020, there was no remaining contingent consideration associated with this transaction.

The Company had continuing involvement related to the lease back of the cast house. As a result, Arconic continued to recognize as assets, as well as depreciate, the cast house building and equipment that it sold to Ta Chen, and recorded the portion of the cash proceeds associated with the sale of the cast house assets as a noncurrent liability, including a deferred gain of $95. As of December 31, 2018, the Company’s Consolidated Balance Sheet included $24 in Properties, plants, and equipment, net, $22 in Deferred income taxes (noncurrent asset), and $119 in Other noncurrent liabilities and deferred credits. On January 1, 2019, Arconic adopted the lease accounting guidance (see Recently Adopted Accounting Guidance in Note B), under which the Company’s continuing involvement no longer required deferral of the recognition of the sale of the cast house. Accordingly, the carrying value of these assets and liabilities were reclassified to equity reflecting a net $73 cumulative effect of an accounting change on the date of adoption.