Proposed Separation Transaction	3 Months Ended
Mar. 31, 2019
Restructuring and Related Activities [Abstract]
Proposed Separation Transaction	Proposed Separation Transaction On February 8, 2019, Arconic announced, as part of its strategy and portfolio review, a separation of its portfolio into two independent, publicly-traded companies. One company will comprise the Engineered Products and Forgings businesses and the other company will comprise the Global Rolled Products businesses. The Company will also consider the sale of businesses that do not best fit into Engineered Products and Forgings and Global Rolled Products. The businesses of the current Transportation and Construction Solutions segment will be divided, with BCS to become part of Global Rolled Products and the Arconic Wheel and Transportation Products business to become part of Engineered Products and Forgings. Arconic is targeting to complete the separation in the second quarter of 2020. The separation transaction is subject to a number of conditions, including, but not limited to, final approval by Arconic’s Board of Directors, receipt of a favorable opinion of legal counsel with respect to the tax-free nature of the transaction for U.S. federal income tax purposes, completion of financing, and the effectiveness of a Form 10 registration statement to be filed with the U.S. Securities and Exchange Commission. Arconic may, at any time and for any reason until the proposed transaction is complete, abandon the separation plan or modify or change its terms. In the first quarter of 2019, Arconic recognized $3 pre-tax in Selling, general administrative, and other expenses on the accompanying Statement of Consolidated Operations for costs related to the proposed separation transaction.

Proposed Separation Transaction

On February 8, 2019, Arconic announced, as part of its strategy and portfolio review, a separation of its portfolio into two independent, publicly-traded companies. One company will comprise the Engineered Products and Forgings businesses and the other company will comprise the Global Rolled Products businesses. The Company will also consider the sale of businesses that do not best fit into Engineered Products and Forgings and Global Rolled Products. The businesses of the current Transportation and Construction Solutions segment will be divided, with BCS to become part of Global Rolled Products and the Arconic Wheel and Transportation Products business to become part of Engineered Products and Forgings. Arconic is targeting to complete the separation in the second quarter of 2020. The separation transaction is subject to a number of conditions, including, but not limited to, final approval by Arconic’s Board of Directors, receipt of a favorable opinion of legal counsel with respect to the tax-free nature of the transaction for U.S. federal income tax purposes, completion of financing, and the effectiveness of a Form 10 registration statement to be filed with the U.S. Securities and Exchange Commission. Arconic may, at any time and for any reason until the proposed transaction is complete, abandon the separation plan or modify or change its terms. In the first quarter of 2019, Arconic recognized $3 pre-tax in Selling, general administrative, and other expenses on the accompanying Statement of Consolidated Operations for costs related to the proposed separation transaction.