Acquisitions and Divestitures	12 Months Ended
Dec. 31, 2017
Business Combinations [Abstract]
Acquisitions and Divestitures	Acquisitions and Divestitures Pro forma results of the Company, assuming all acquisitions described below were made at the beginning of the earliest prior period presented, would not have been materially different from the results reported. 2017 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 D) on the Statement of Consolidated Operations for 2017. The rolling mill generated third-party sales of approximately $54 and $165 for 2017 and 2016, respectively. At the time of the divestiture, the rolling mill had approximately 312 employees. In December 2017, Arconic entered into an agreement to sell its Latin America Extrusions business for $10 million in cash, subject to working capital and other adjustments. The Latin America Extrusions business operates primarily in Brazil and is part of the Company’s Transportation and Construction Solutions segment. Following customary regulatory and anti-trust approvals, the ownership of this business is expected to be transferred to a subsidiary of Hydro Extruded Solutions AS in the first half of 2018. As a result of the transaction, Arconic recognized a charge of $41 million in the fourth quarter of 2017 primarily related to the non-cash impairment of the net book value of the business (See Notes A and D). 2016 Divestitures. In April 2016, Arconic completed the sale of the Remmele Medical business to LISI MEDICAL for $102 in cash ($99 net of transaction costs), which was included in Proceeds from the sale of assets and businesses on the accompanying Statement of Consolidated Cash Flows. This business, which was part of the RTI International Metals Inc. (RTI) acquisition (see below), manufactured precision-machined metal products for customers in the minimally invasive surgical device and implantable device markets. Since this transaction occurred within a year of the completion of the RTI acquisition, no gain was recorded on this transaction as the excess of the proceeds over the carrying value of the net assets of this business was reflected as a purchase price adjustment (decrease to goodwill of $44) to the final allocation of the purchase price related to Arconic’s acquisition of RTI. While owned by Arconic, the operating results and assets and liabilities of this business were included in the Engineered Products and Solutions segment. This business generated sales of approximately $20 from January 1, 2016 through the divestiture date, April 29, 2016, and, at the time of the divestiture, had approximately 330 employees. 2015 Acquisitions. In March 2015, Arconic completed the acquisition of an aerospace structural castings company, TITAL, for $204 (€188) in cash (an additional $1 (€1) was paid in September 2015 to settle working capital in accordance with the purchase agreement). TITAL, a privately held company with approximately 650 employees at the time of the acquisition and based in Germany, produces aluminum and titanium investment casting products for the aerospace and defense markets. The purpose of this acquisition was to capture increasing demand for advanced jet engine components made of titanium, establish titanium-casting capabilities in Europe, and expand existing aluminum casting capacity. The assets, including the associated goodwill, and liabilities of this business were included within Arconic’s Engineered Products and Solutions segment since the date of acquisition. Based on the preliminary allocation of the purchase price, goodwill of $118 was recorded for this transaction. In the first quarter of 2016, the allocation of the purchase price was finalized, based, in part, on the completion of a third-party valuation of certain assets acquired, resulting in a $1 reduction of the initial goodwill amount. None of the $117 in goodwill is deductible for income tax purposes and no other intangible assets were identified. In July 2015, Arconic completed the acquisition of RTI, a U.S. company that was publicly traded on the New York Stock Exchange under the ticker symbol “RTI.” Arconic purchased all outstanding shares of RTI common stock in a stock-for-stock transaction valued at $870 (based on the $9.96 per share July 23, 2015 closing price of Arconic’s common stock). Each issued and outstanding share of RTI common stock prior to the completion of the transaction was converted into the right to receive 2.8315 shares of Arconic common stock. In total, Arconic issued 29,132,471 shares (87,397,414 shares pre-reverse stock split – see Note O) of its common stock to consummate this transaction, which was not reflected in the accompanying Statement of Consolidated Cash Flows as it represents a noncash financing activity. The exchange ratio was the quotient of a $41 per RTI common share acquisition price and the $14.48 per share March 6, 2015 closing price of Arconic’s common stock. In addition to the transaction price, Arconic also paid $25 ($19 after-tax) in professional fees and costs related to this acquisition. This amount was recorded in Selling, general administrative, and other expenses on the accompanying Statement of Consolidated Operations. RTI is a global supplier of titanium and specialty metal products and services for the commercial aerospace, defense, energy, and medical device end markets. The purpose of this acquisition was to expand Arconic’s range of titanium offerings and add advanced technologies and materials, primarily related to the aerospace end market. In 2014, RTI generated net sales of $794 and had approximately 2,600 employees. The operating results and assets and liabilities of RTI were included within Arconic’s Engineered Products and Solutions segment since the date of acquisition. Third-party sales and Adjusted EBITDA (Arconic’s primary segment performance measure – see Note N) of RTI from the acquisition date through December 31, 2015 were $309 and $21, respectively. During the third quarter of 2016, the final purchase price allocation was completed. Arconic recognized goodwill of $298, which represents the earnings growth potential of RTI, Arconic’s ability to expand its titanium capabilities in the aerospace market, and expected synergies from combining the operations of the two companies. This goodwill was allocated to a new Arconic reporting unit associated with the Engineered Products and Solutions segment, ATEP, which consists solely of the acquired RTI business. None of this goodwill is deductible for income tax purposes. Arconic also recorded intangible assets of $37 consisting mainly of customer relationships which are being amortized over a period of 20 years. As part of this acquisition, Arconic assumed the obligation to repay two tranches of convertible debt; one tranche was due and settled in cash on December 1, 2015 (principal amount of $115) and the other tranche is due on October 15, 2019 (principal amount of $403), unless earlier converted or purchased by Arconic at the holder’s option under specific conditions. Upon conversion of the 2019 convertible notes, holders will receive, at Arconic’s election, cash, shares of common stock (approximately 14,294,000 shares using the December 31, 2017 conversion rate of 35.5119 shares per $1,000 (not in millions) bond or per-share conversion price of $28.1596), or a combination of cash and shares. On the maturity date, each holder of outstanding notes will be entitled to receive $1,000 (not in millions) in cash for each $1,000 (not in millions) bond, together with accrued and unpaid interest. The cash conversion feature requires the convertible notes to be bifurcated into a liability component and an equity component. The fair value of the liability component was determined by calculating the net present value of the cash flows of the convertible notes using the interest rate of a similar instrument without a conversion feature. The fair value of the equity component is the difference between the fair value of the entire instrument on the date of acquisition and the fair value of the liability and is included as Additional capital on the accompanying Consolidated Balance Sheet. 2015 Divestitures. In 2015, Arconic completed the divestiture of an operation in Russia (see below) and had post-closing adjustments, as provided for in the respective purchase agreements, related to a divestiture completed in December 2014. The divestiture and post-closing adjustments combined resulted in net cash paid of $11 and a net loss of $137, which was recorded in Restructuring and other charges (see Note D) on the accompanying Statement of Consolidated Operations. In March 2015, Arconic completed the sale of a rolling mill located in Belaya Kalitva, Russia to a wholly-owned subsidiary of Stupino Titanium Company. While owned by Arconic, the operating results and assets and liabilities of the rolling mill were included in the Global Rolled Products segment. The rolling mill generated sales of approximately $130 in 2014 and, at the time of divestiture, had approximately 1,870 employees. 2014 Acquisitions. In November 2014, Arconic acquired Firth Rixson. The purchase price included an earn-out agreement that required Arconic to make earn-out payments up to an aggregate maximum amount of $150 through December 31, 2020 upon certain conditions. This earn-out was contingent on the Firth Rixson forging business in Savannah, Georgia achieving certain identified financial targets through December 31, 2020. During the fourth quarter of 2016, management determined that payment of the maximum amount was not probable based on the forecasted financial performance of this location. Therefore, the fair value of this liability was reduced by $56 with a corresponding credit to Other income, net on the accompanying Statement of Consolidated Operations. During the fourth quarter of 2017, management determined that payment of the remaining amount of the contingent liability was not probable based on the forecasted financial performance of this location. Therefore, the fair value of this liability was reduced by $81 to zero at December 31, 2017 with a corresponding credit to Other income, net on the accompanying Statement of Consolidated Operations.

Acquisitions and Divestitures

Pro forma results of the Company, assuming all acquisitions described below were made at the beginning of the earliest prior period presented, would not have been materially different from the results reported.

2017 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 D) on the Statement of Consolidated Operations for 2017. The rolling mill generated third-party sales of approximately $54 and $165 for 2017 and 2016, respectively. At the time of the divestiture, the rolling mill had approximately 312 employees.

In December 2017, Arconic entered into an agreement to sell its Latin America Extrusions business for $10 million in cash, subject to working capital and other adjustments. The Latin America Extrusions business operates primarily in Brazil and is part of the Company’s Transportation and Construction Solutions segment. Following customary regulatory and anti-trust approvals, the ownership of this business is expected to be transferred to a subsidiary of Hydro Extruded Solutions AS in the first half of 2018. As a result of the transaction, Arconic recognized a charge of $41 million in the fourth quarter of 2017 primarily related to the non-cash impairment of the net book value of the business (See Notes A and D).

2016 Divestitures. In April 2016, Arconic completed the sale of the Remmele Medical business to LISI MEDICAL for $102 in cash ($99 net of transaction costs), which was included in Proceeds from the sale of assets and businesses on the accompanying Statement of Consolidated Cash Flows. This business, which was part of the RTI International Metals Inc. (RTI) acquisition (see below), manufactured precision-machined metal products for customers in the minimally invasive surgical device and implantable device markets. Since this transaction occurred within a year of the completion of the RTI acquisition, no gain was recorded on this transaction as the excess of the proceeds over the carrying value of the net assets of this business was reflected as a purchase price adjustment (decrease to goodwill of $44) to the final allocation of the purchase price related to Arconic’s acquisition of RTI. While owned by Arconic, the operating results and assets and liabilities of this business were included in the Engineered Products and Solutions segment. This business generated sales of approximately $20 from January 1, 2016 through the divestiture date, April 29, 2016, and, at the time of the divestiture, had approximately 330 employees.

2015 Acquisitions. In March 2015, Arconic completed the acquisition of an aerospace structural castings company, TITAL, for $204 (€188) in cash (an additional $1 (€1) was paid in September 2015 to settle working capital in accordance with the purchase agreement). TITAL, a privately held company with approximately 650 employees at the time of the acquisition and based in Germany, produces aluminum and titanium investment casting products for the aerospace and defense markets. The purpose of this acquisition was to capture increasing demand for advanced jet engine components made of titanium, establish titanium-casting capabilities in Europe, and expand existing aluminum casting capacity. The assets, including the associated goodwill, and liabilities of this business were included within Arconic’s Engineered Products and Solutions segment since the date of acquisition. Based on the preliminary allocation of the purchase price, goodwill of $118 was recorded for this transaction. In the first quarter of 2016, the allocation of the purchase price was finalized, based, in part, on the completion of a third-party valuation of certain assets acquired, resulting in a $1 reduction of the initial goodwill amount. None of the $117 in goodwill is deductible for income tax purposes and no other intangible assets were identified.

In July 2015, Arconic completed the acquisition of RTI, a U.S. company that was publicly traded on the New York Stock Exchange under the ticker symbol “RTI.” Arconic purchased all outstanding shares of RTI common stock in a stock-for-stock transaction valued at $870 (based on the $9.96 per share July 23, 2015 closing price of Arconic’s common stock). Each issued and outstanding share of RTI common stock prior to the completion of the transaction was converted into the right to receive 2.8315 shares of Arconic common stock. In total, Arconic issued 29,132,471 shares (87,397,414 shares pre-reverse stock split – see Note O) of its common stock to consummate this transaction, which was not reflected in the accompanying Statement of Consolidated Cash Flows as it represents a noncash financing activity. The exchange ratio was the quotient of a $41 per RTI common share acquisition price and the $14.48 per share March 6, 2015 closing price of Arconic’s common stock. In addition to the transaction price, Arconic also paid $25 ($19 after-tax) in professional fees and costs related to this acquisition. This amount was recorded in Selling, general administrative, and other expenses on the accompanying Statement of Consolidated Operations.

RTI is a global supplier of titanium and specialty metal products and services for the commercial aerospace, defense, energy, and medical device end markets. The purpose of this acquisition was to expand Arconic’s range of titanium offerings and add advanced technologies and materials, primarily related to the aerospace end market. In 2014, RTI generated net sales of $794 and had approximately 2,600 employees. The operating results and assets and liabilities of RTI were included within Arconic’s Engineered Products and Solutions segment since the date of acquisition. Third-party sales and Adjusted EBITDA (Arconic’s primary segment performance measure – see Note N) of RTI from the acquisition date through December 31, 2015 were $309 and $21, respectively. During the third quarter of 2016, the final purchase price allocation was completed.

Arconic recognized goodwill of $298, which represents the earnings growth potential of RTI, Arconic’s ability to expand its titanium capabilities in the aerospace market, and expected synergies from combining the operations of the two companies. This goodwill was allocated to a new Arconic reporting unit associated with the Engineered Products and Solutions segment, ATEP, which consists solely of the acquired RTI business. None of this goodwill is deductible for income tax purposes. Arconic also recorded intangible assets of $37 consisting mainly of customer relationships which are being amortized over a period of 20 years.

As part of this acquisition, Arconic assumed the obligation to repay two tranches of convertible debt; one tranche was due and settled in cash on December 1, 2015 (principal amount of $115) and the other tranche is due on October 15, 2019 (principal amount of $403), unless earlier converted or purchased by Arconic at the holder’s option under specific conditions. Upon conversion of the 2019 convertible notes, holders will receive, at Arconic’s election, cash, shares of common stock (approximately 14,294,000 shares using the December 31, 2017 conversion rate of 35.5119 shares per $1,000 (not in millions) bond or per-share conversion price of $28.1596), or a combination of cash and shares. On the maturity date, each holder of outstanding notes will be entitled to receive $1,000 (not in millions) in cash for each $1,000 (not in millions) bond, together with accrued and unpaid interest. The cash conversion feature requires the convertible notes to be bifurcated into a liability component and an equity component. The fair value of the liability component was determined by calculating the net present value of the cash flows of the convertible notes using the interest rate of a similar instrument without a conversion feature. The fair value of the equity component is the difference between the fair value of the entire instrument on the date of acquisition and the fair value of the liability and is included as Additional capital on the accompanying Consolidated Balance Sheet.

2015 Divestitures. In 2015, Arconic completed the divestiture of an operation in Russia (see below) and had post-closing adjustments, as provided for in the respective purchase agreements, related to a divestiture completed in December 2014. The divestiture and post-closing adjustments combined resulted in net cash paid of $11 and a net loss of $137, which was recorded in Restructuring and other charges (see Note D) on the accompanying Statement of Consolidated Operations.

In March 2015, Arconic completed the sale of a rolling mill located in Belaya Kalitva, Russia to a wholly-owned subsidiary of Stupino Titanium Company. While owned by Arconic, the operating results and assets and liabilities of the rolling mill were included in the Global Rolled Products segment. The rolling mill generated sales of approximately $130 in 2014 and, at the time of divestiture, had approximately 1,870 employees.

2014 Acquisitions. In November 2014, Arconic acquired Firth Rixson. The purchase price included an earn-out agreement that required Arconic to make earn-out payments up to an aggregate maximum amount of $150 through December 31, 2020 upon certain conditions. This earn-out was contingent on the Firth Rixson forging business in Savannah, Georgia achieving certain identified financial targets through December 31, 2020. During the fourth quarter of 2016, management determined that payment of the maximum amount was not probable based on the forecasted financial performance of this location. Therefore, the fair value of this liability was reduced by $56 with a corresponding credit to Other income, net on the accompanying Statement of Consolidated Operations. During the fourth quarter of 2017, management determined that payment of the remaining amount of the contingent liability was not probable based on the forecasted financial performance of this location. Therefore, the fair value of this liability was reduced by $81 to zero at December 31, 2017 with a corresponding credit to Other income, net on the accompanying Statement of Consolidated Operations.