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Other Financial Instruments (Tables) | 12 Months Ended
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Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract] |
Schedule of Carrying Values and Fair Values of Other Financial Instruments | The carrying values of Cash and cash equivalents, Restricted cash, Derivatives, Noncurrent receivables and Short-term debt included in the Consolidated Balance Sheet approximate their fair values. The Company holds exchange-traded fixed income securities which are considered available-for-sale securities that are carried at fair value which is based on quoted market prices which are classified in Level 1 of the fair value hierarchy. The fair value of Long-term debt, less amount due within one year was based on quoted market prices for public debt and on interest rates that are currently available to Arconic for issuance of debt with similar terms and maturities for non-public debt. The fair value amounts for all Long-term debt were classified in Level 2 of the fair value hierarchy.
| 2018 |  | 2017
December 31, | Carrying value |  | Fair value |  | Carrying value |  | Fair value
Long-term debt, less amount due within one year | 5,896 |  |  | 5,873 |  |  | 6,806 |  |  | 7,443 |

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