Recently Adopted and Recently Issued Accounting Guidance (Policies)	6 Months Ended
Jun. 30, 2023
Accounting Policies [Abstract]
Recent Accounting Guidance	Adopted On January 1, 2023, Arconic adopted changes issued by the Financial Accounting Standards Board (FASB) to the disclosure of supplier finance programs. The FASB issued this guidance to address a perceived lack of transparency about such programs, which may prevent an understanding by financial statement users of the effect these programs have on an entity’s working capital, liquidity, and cash flows. Supplier finance programs (also may be referred to as reverse factoring, payables finance, or structured payables arrangements) allow a buyer to offer its suppliers the option for access to payment in advance of an invoice due date, which is paid by a third-party finance provider or intermediary on the basis of invoices that the buyer has confirmed as valid. Generally, a buyer (i) enters into an agreement with a finance provider or an intermediary to establish the program, (ii) purchases goods and services from suppliers with a promise to pay at a later date, and (iii) notifies the finance provider or intermediary of the supplier invoices that it has confirmed as valid. The suppliers may then request early payment directly from the finance provider or intermediary for those confirmed invoices. In the fiscal year of adoption, the guidance requires a buyer in a supplier finance program to disclose the following information in all reporting periods: (i) the key terms of the program, including a description of the payment terms and any assets pledged as security or other forms of guarantees provided for the committed payment to the finance provider or intermediary, and (ii) for the obligations that the buyer has confirmed as valid to the finance provider or intermediary, the amount outstanding that remains unpaid by the buyer as of the end of the reporting period and a description of where those obligations are presented in the balance sheet. In subsequent years, only the amount of obligations outstanding that the buyer has confirmed as valid to the finance provider or intermediary as of the end of the reporting period is required disclosure for interim periods while all the previously mentioned information is required disclosure for annual periods, including an incremental requirement to present a roll forward of the obligations, including the amount of obligations confirmed and the amount of obligations subsequently paid. The Company has an existing arrangement with a financial institution to make available this type of program to its suppliers. Other than disclosing the required information (see Note R), the adoption of this guidance did not have an impact on the Consolidated Financial Statements. Issued In March 2020, the FASB issued guidance that provides optional expedients and exceptions for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. These expedients and exceptions may be used when applying GAAP, if certain criteria are met, to contracts, hedging relationships, and other transactions that reference London Inter-Bank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of such reform. The purpose of this guidance is to provide relief to entities from experiencing unintended accounting and/or financial reporting outcomes or consequences due to reference rate reform. This guidance became effective immediately on March 12, 2020 and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022, after which time the expedients and exceptions expire (see below). In January 2021, the FASB issued clarifying guidance to specify that certain of the optional expedients and exceptions apply to derivatives that use an interest rate for margining, discounting, or contract price alignment that is modified as a result of reference rate reform. This additional guidance may be applied on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively in the manner previously described for the guidance issued on March 12, 2020. In December 2022, the FASB extended the expiration of the optional expedients and exceptions to December 31, 2024. Through June 30, 2023, Arconic has not experienced any unintended outcomes or consequences of reference rate reform that would necessitate the adoption of this guidance. Additionally, the Company’s credit agreement, which previously provided a credit facility that was referenced to LIBOR in certain borrowing situations, was amended in February 2022 to replace LIBOR with the Secured Overnight Financing Rate (SOFR) (see Note N). Management will continue to closely monitor all potential instances of reference rate reform to determine if adoption of this guidance becomes necessary in the future.

On January 1, 2023, Arconic adopted changes issued by the Financial Accounting Standards Board (FASB) to the disclosure of supplier finance programs. The FASB issued this guidance to address a perceived lack of transparency about such programs, which may prevent an understanding by financial statement users of the effect these programs have on an entity’s working capital, liquidity, and cash flows. Supplier finance programs (also may be referred to as reverse factoring, payables finance, or structured payables arrangements) allow a buyer to offer its suppliers the option for access to payment in advance of an invoice due date, which is paid by a third-party finance provider or intermediary on the basis of invoices that the buyer has confirmed as valid. Generally, a buyer (i) enters into an agreement with a finance provider or an intermediary to establish the program, (ii) purchases goods and services from suppliers with a promise to pay at a later date, and (iii) notifies the finance provider or intermediary of the supplier invoices that it has confirmed as valid. The suppliers may then request early payment directly from the finance provider or intermediary for those confirmed invoices. In the fiscal year of adoption, the guidance requires a buyer in a supplier finance program to disclose the following information in all reporting periods: (i) the key terms of the program, including a description of the payment terms and any assets pledged as security or other forms of guarantees provided for the committed payment to the finance provider or intermediary, and (ii) for the obligations that the buyer has confirmed as valid to the finance provider or intermediary, the amount outstanding that remains unpaid by the buyer as of the end of the reporting period and a description of where those obligations are presented in the balance sheet. In subsequent years, only the amount of obligations outstanding that the buyer has confirmed as valid to the finance provider or intermediary as of the end of the reporting period is required disclosure for interim periods while all the previously mentioned information is required disclosure for annual periods, including an incremental requirement to present a roll forward of the obligations, including the amount of obligations confirmed and the amount of obligations subsequently paid. The Company has an existing arrangement with a financial institution to make available this type of program to its suppliers. Other than disclosing the required information (see Note R), the adoption of this guidance did not have an impact on the Consolidated Financial Statements.

In March 2020, the FASB issued guidance that provides optional expedients and exceptions for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. These expedients and exceptions may be used when applying GAAP, if certain criteria are met, to contracts, hedging relationships, and other transactions that reference London Inter-Bank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of such reform. The purpose of this guidance is to provide relief to entities from experiencing unintended accounting and/or financial reporting outcomes or consequences due to reference rate reform. This guidance became effective immediately on March 12, 2020 and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022, after which time the expedients and exceptions expire (see below). In January 2021, the FASB issued clarifying guidance to specify that certain of the optional expedients and exceptions apply to derivatives that use an interest rate for margining, discounting, or contract price alignment that is modified as a result of reference rate reform. This additional guidance may be applied on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively in the manner previously described for the guidance issued on March 12, 2020. In December 2022, the FASB extended the expiration of the optional expedients and exceptions to December 31, 2024. Through June 30, 2023, Arconic has not experienced any unintended outcomes or consequences of reference rate reform that would necessitate the adoption of this guidance. Additionally, the Company’s credit agreement, which previously provided a credit facility that was referenced to LIBOR in certain borrowing situations, was amended in February 2022 to replace LIBOR with the Secured Overnight Financing Rate (SOFR) (see Note N). Management will continue to closely monitor all potential instances of reference rate reform to determine if adoption of this guidance becomes necessary in the future.