Cash Equivalents. Cash equivalents are highly liquid investments purchased with an original maturity of three months or less.

Inventory Valuation. Inventories are carried at the lower of cost or market, with the cost of inventories principally determined under the average cost method.

Effective January 1, 2019, the Company changed its accounting method for valuing certain inventories from last-in, first-out (LIFO) to the average cost method. The effects of the change in accounting principle have been retrospectively applied to all prior periods presented in the Company’s Consolidated Financial Statements. See Note I for additional information.

Properties, Plants, and Equipment. Properties, plants, and equipment are recorded at cost. Interest related to the construction of qualifying assets is capitalized as part of the construction costs. Depreciation is recorded principally on the straight-line method over the estimated useful lives of the assets. Depreciation is recorded on temporarily idled facilities until such time management approves a permanent closure. The following table details the weighted-average useful lives of structures and machinery and equipment by type of operation (numbers in years):

	Structures		Machinery and equipment
Bauxite mining		35		17
Alumina refining		28		29
Aluminum smelting and casting		37		23
Energy generation		33		24
Aluminum rolling		31		21

Repairs and maintenance are charged to expense as incurred while costs for significant improvements that add productive capacity or that extend the useful life are capitalized. Gains or losses from the sale of assets are generally recorded in Other expenses, net. Properties, plants, and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets (asset group) may not be recoverable.

Leases. The Company determines whether an arrangement is a lease at the inception of the arrangement based on the terms and conditions in the contract. A contract contains a lease if there is an identified asset which the Company has the right to control. Both operating and financing lease right-of-use (ROU) assets are included in Properties, plants, and equipment with the corresponding operating lease liabilities included within Other current liabilities and Other noncurrent liabilities and deferred credits, while financing lease liabilities are included in Long-term debt due within one year and Long-term debt, less amount due within one year on the Consolidated Balance Sheet.

Operating lease ROU assets and liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. The Company uses its incremental borrowing rate at the commencement date in determining the present value of lease payments unless a rate is implicit in the lease. Lease terms include options to extend the lease when it is reasonably certain that those options will be exercised. Leases with an initial term of 12 months or less, including anticipated renewals, are not recorded on the balance sheet.

The Company has made a policy election not to record any non-lease components of a lease agreement in the lease liability. Variable lease payments are not presented as part of the initial ROU asset or liability recorded at the inception of a contract. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. For finance leases, interest expense is recognized on the lease liability and the ROU asset is amortized over the lease term.

Equity Investments. Alcoa invests in a number of privately-held companies, primarily through joint ventures and consortia, which are accounted for using the equity method. The equity method is applied in situations where the Company has the ability to exercise significant influence, but not control, over the investee. Management reviews equity investments for impairment whenever certain indicators are present suggesting that the carrying value of an investment is not recoverable.

Deferred Mining Costs. Alcoa recognizes deferred mining costs during the development stage of a mine life cycle. Such costs include the construction of access and haul roads, detailed drilling and geological analysis to further define the grade and quality of the known bauxite, and overburden removal costs. These costs relate to sections of the related mines where the Company is currently extracting bauxite or preparing for production in the near term. These sections are outlined and planned incrementally and generally are mined over periods ranging from one to five years, depending on mine specifics. The amount of geological drilling and testing necessary to determine the economic viability of the bauxite deposit being mined is such that the reserves are considered to be proven, and the mining costs are amortized based on this level of reserves. Deferred mining costs are included in Other noncurrent assets on the accompanying Consolidated Balance Sheet.

Goodwill and Other Intangible Assets. Goodwill is not amortized but is reviewed for impairment annually (in the fourth quarter) or more frequently if indicators of impairment exist or if a decision is made to sell or exit a business.

Goodwill is allocated among and evaluated for impairment at the reporting unit level, which is defined as an operating segment or one level below an operating segment. The Company has five reporting units, of which three are included in the Aluminum segment (smelting/casting, energy generation, and rolling operations). The remaining two reporting units are the Bauxite and Alumina segments. Of these five reporting units, only Bauxite and Alumina contain goodwill. As of December 31, 2019, the carrying value of the goodwill for Bauxite and Alumina was $50 and $100, respectively. These amounts include an allocation of goodwill held at the corporate level (see Note K).

Goodwill is tested for impairment by assessing qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount or performing a quantitative assessment using a discounted cash flow method. The qualitative assessment considers factors such as general economic conditions, equity and credit markets, industry and market conditions, and earnings and cash flow trends. If the qualitative assessment indicates a possible impairment, then a quantitative impairment test is performed to determine the fair value of the reporting unit using a discounted cash flow method. Otherwise, no further analysis is required. Alcoa’s policy for its annual review of goodwill is to perform the quantitative impairment test for each of its two reporting units that contain goodwill at least once during every three-year period as part of its annual review of goodwill.

Intangible assets with finite useful lives are amortized generally on a straight-line basis over the periods benefited. The following table details the weighted-average useful lives of software and other intangible assets by type of operation (numbers in years):

	Software		Other intangible assets
Bauxite mining		3		10
Alumina refining		7		21
Aluminum smelting and casting		3		39
Energy generation		—		29
Aluminum rolling		3		20

Asset Retirement Obligations. Alcoa recognizes asset retirement obligations (AROs) related to legal obligations associated with the standard operation of bauxite mines, alumina refineries, and aluminum smelters. These AROs consist primarily of costs associated with mine reclamation, closure of bauxite residue areas, spent pot lining and regulated waste materials disposal, and landfill closure. Additionally, costs are recorded as AROs upon management’s decision to permanently close and demolish certain structures and for any significant lease restoration obligations. The fair values of these AROs are recorded on a discounted basis at the time the obligation is incurred and accreted over time for the change in present value. Additionally, the Company capitalizes asset retirement costs by increasing the carrying amount of the related long-lived assets and depreciating these assets over their remaining useful life. Certain conditional asset retirement obligations related to alumina refineries, aluminum smelters, rolling mills, and energy generation facilities have not been recorded in the Consolidated Financial Statements due to uncertainties surrounding the ultimate settlement date. The fair value of these asset retirement obligations will be recorded when a reasonable estimate of the ultimate settlement date can be made.

Environmental Matters. Environmental related expenditures for current operations are expensed or capitalized, as appropriate. Expenditures relating to existing conditions caused by past operations, which will not contribute to future revenues, are expensed. Liabilities are recorded when remediation costs are probable and can be reasonably estimated. The estimates also include costs related to other potentially responsible parties to the extent that Alcoa has reason to believe such parties will not fully pay their proportionate share. In instances where the Company has ongoing monitoring and maintenance responsibilities, it is Alcoa’s policy to maintain a reserve equal to five years of expected costs. The liability is continuously reviewed and adjusted to reflect current remediation progress, prospective estimates of required activity, and other factors that may be relevant, including changes in technology or regulations.

Litigation Matters. For asserted claims and assessments, liabilities are recorded when an unfavorable outcome of a matter is deemed to be probable and the loss is reasonably estimable. With respect to unasserted claims or assessments, management

must first determine that the probability that an assertion will be made is likely. Then, a determination as to the likelihood of an unfavorable outcome and the ability to reasonably estimate the potential loss is made. Legal matters are reviewed on a continuous basis to determine if there has been a change in management’s judgment regarding the likelihood of an unfavorable outcome or the estimate of a potential loss. Legal costs, which are primarily for general litigation, environmental compliance, tax disputes, and general corporate matters, are expensed as incurred.

Revenue Recognition. The Company recognizes revenue when it satisfies a performance obligation(s) in accordance with the provisions of a customer order or contract. This is achieved when control of the product has been transferred to the customer, which is generally determined when title, ownership, and risk of loss pass to the customer, all of which occurs upon shipment or delivery of the product. The shipping terms vary across all businesses and depend on the product, the country of origin, and the type of transportation. Accordingly, the sale of Alcoa’s products to its customers represent single performance obligations for which revenue is recognized at a point in time. Revenue is based on the consideration it expects to receive in exchange for its products. Returns and other adjustments have not been material. Based on the foregoing, no significant judgment is required to determine when control of a product has been transferred to a customer.

The Company considers shipping and handling activities as costs to fulfill the promise to transfer the related products. As a result, customer payments of shipping and handling costs are recorded as a component of revenue. Taxes collected (e.g., sales, use, value-added, excise) from its customers related to the sale of its products are remitted to governmental authorities and excluded from revenue.

Stock-Based Compensation. Compensation expense for employee equity grants is recognized using the non-substantive vesting period approach, in which the expense (net of estimated forfeitures) is recognized ratably over the requisite service period based on the grant date fair value. The fair value of new stock options is estimated on the date of grant using a lattice-pricing model. Determining the fair value of stock options at the grant date requires judgment, including estimates for the average risk-free interest rate, dividend yield, volatility, annual forfeiture rate, and exercise behavior. These assumptions may differ significantly between grant dates because of changes in the actual results of these inputs that occur over time.

Most plan participants can choose whether to receive their award in the form of stock options, stock units, or a combination of both. This choice is made before the grant is issued and is irrevocable.

Pension and Other Postretirement Benefits. Liabilities and expenses for pension and other postretirement benefits are determined using actuarial methodologies and incorporate significant assumptions, including the interest rate used to discount the future estimated liability, the expected long-term rate of return on plan assets, and several assumptions relating to the employee workforce (salary increases, health care cost trend rates, retirement age, and mortality).

The yield curve model used to develop the discount rate parallels the plans’ projected cash flows and has a weighted average duration of 11 years. The underlying cash flows of the high quality corporate bonds included in the model exceed the cash flows needed to satisfy the Company’s plan obligations multiple times. If a deep market of high quality corporate bonds does not exist in a country, then the yield on government bonds plus a corporate bond yield spread is used.

The expected long-term rate of return on plan assets is generally applied to a five-year market-related value of plan assets (a four-year average or the fair value at the plan measurement date is used for certain non-U.S. plans). The process used by management to develop this assumption is one that relies on forward-looking investment returns by asset class. Management incorporates expected future investment returns on current and planned asset allocations using information from various external investment managers and consultants, as well as management’s own judgment.

Mortality rate assumptions are based on mortality tables and future improvement scales published by third parties, such as the Society of Actuaries, and consider other available information including historical data as well as studies and publications from reputable sources.

Derivatives and Hedging. Derivatives are held for purposes other than trading and are part of a formally documented risk management program.

Alcoa accounts for hedges of firm customer commitments for aluminum as fair value hedges. The fair values of the derivatives and changes in the fair values of the underlying hedged items are reported as assets and liabilities in the Consolidated Balance Sheet. Changes in the fair values of these derivatives and underlying hedged items generally offset and are recorded each period in Sales, consistent with the underlying hedged item.

The Company accounts for hedges of foreign currency exposures and certain forecasted transactions as cash flow hedges. The fair values of the derivatives are recorded as assets and liabilities in the Consolidated Balance Sheet. The changes in the fair values of these derivatives are recorded in Other comprehensive (loss) income and are reclassified to Sales, Cost of goods sold, or Other expenses, net in the period in which earnings are impacted by the hedged items or in the period that the transaction no longer qualifies as a cash flow hedge. These contracts cover the same periods as known or expected exposures, generally not exceeding five years.

If no hedging relationship is designated, the derivative is marked to market through Other expenses, net.

Cash flows from derivatives are recognized in the Statement of Consolidated Cash Flows in a manner consistent with the underlying transactions.

Income Taxes. The provision for income taxes is determined using the asset and liability approach of accounting for income taxes. Under this approach, the provision for income taxes represents income taxes paid or payable (or received or receivable) for the current year plus the change in deferred taxes during the year. Deferred taxes represent the future tax consequences expected to occur when the reported amounts of assets and liabilities are recovered or paid and result from differences between the financial and tax bases of Alcoa’s assets and liabilities and are adjusted for changes in tax rates and tax laws when enacted.

Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not (greater than 50%) that a tax benefit will not be realized. In evaluating the need for a valuation allowance, management applies judgement in assessing all available positive and negative evidence and considers all potential sources of taxable income, including income available in carryback periods, future reversals of taxable temporary differences, projections of taxable income, and income from tax planning strategies. Positive evidence includes factors such as a history of profitable operations, projections of future profitability within the carryforward period, including from tax planning strategies, and Alcoa’s experience with similar operations. Existing favorable contracts and the ability to sell products into established markets are additional positive evidence. Negative evidence includes items such as cumulative losses, projections of future losses, or carryforward periods that are not long enough to allow for the utilization of a deferred tax asset based on existing projections of income. Deferred tax assets for which no valuation allowance is recorded may not be realized upon changes in facts and circumstances, resulting in a future charge to establish a valuation allowance. Existing valuation allowances are re-examined under the same standards of positive and negative evidence. If it is determined that it is more likely than not that a deferred tax asset will be realized, the appropriate amount of the valuation allowance, if any, is released. Deferred tax assets and liabilities are also re-measured to reflect changes in underlying tax rates due to law changes and the granting and lapse of tax holidays.

Tax benefits related to uncertain tax positions taken or expected to be taken on a tax return are recorded when such benefits meet a more likely than not threshold. Otherwise, these tax benefits are recorded when a tax position has been effectively settled, which means that the statute of limitation has expired or the appropriate taxing authority has completed their examination even though the statute of limitations remains open. Interest and penalties related to uncertain tax positions are recognized as part of the provision for income taxes and are accrued beginning in the period that such interest and penalties would be applicable under relevant tax law until such time that the related tax benefits are recognized.

Foreign Currency. The local currency is the functional currency for Alcoa’s significant operations outside the United States, except for certain operations in Canada and Iceland, where the U.S. dollar is used as the functional currency. The determination of the functional currency for Alcoa’s operations is made based on the appropriate economic and management indicators. Where local currency is the functional currency, assets and liabilities are translated into U.S. dollars using year-end exchange rates and income and expenses are translated using the average exchange rates for the reporting period. Unrealized foreign currency translation gains and losses are deferred in Accumulated other comprehensive loss on the Consolidated Balance Sheet.

Recently Adopted Accounting Guidance. On January 1, 2019, the Company adopted Accounting Standards Update (ASU) No. 2016-02, Leases, issued by the Financial Accounting Standards Board (FASB) regarding the accounting for leases, using the modified retrospective approach. This ASU requires lessees to recognize a right-of-use asset and lease liability on the balance sheet for operating and finance leases with a term of 12 months or more. Additionally, when measuring assets and liabilities arising from a lease, optional payments should be included only if the lessee is reasonably certain to exercise an option to extend the lease, exercise a purchase option, or not exercise an option to terminate the lease. A right-of-use asset represents an entity’s right to use the underlying asset for the lease term, and a lease liability represents an entity’s obligation to make lease payments. The Company has made a policy election not to record any non-lease components in the lease liability. Previously, an asset and liability were only recorded for leases classified as capital leases (financing leases). The measurement, recognition, and presentation of expenses and cash flows arising from leases by a lessee remains the same. Management elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed carry forward of historical lease classifications. Additionally, in July 2018, the FASB issued ASU No. 2018-11, Targeted Improvements, to provide for an alternative transition method to the new lease guidance, whereby an entity can choose to not reflect the impact of the new lease guidance in the prior periods included in its financial statements. The Company elected this alternative transition method upon adoption on January 1, 2019. Management also elected the practical expedient related to land easements, allowing the Company to carry forward the current treatment on existing arrangements.

As a result of the adoption, management recorded a right-of-use asset and lease liability, each in the amount of $201, on Alcoa’s Consolidated Balance Sheet as of January 1, 2019 for several types of operating leases, including land and buildings,

alumina refinery process control technology, plant equipment, vehicles, and computer equipment. See Note S for additional information related to the adoption of this standard.

Alcoa’s adoption of the following accounting guidance in 2019 did not have a material impact on the Company’s Consolidated Financial Statements:

2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income

2018-07 Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting

Recently Issued Accounting Guidance. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740) which is intended to simply the accounting for income taxes by eliminating certain exceptions and simplifying certain requirements under Topic 740. Updates are related to intraperiod tax allocation, deferred tax liabilities for equity method investments, interim period tax calculations, tax laws or rate changes in interim periods, and income taxes related to employee stock ownership plans. The guidance for ASU No. 2019-12 becomes effective for Alcoa on January 1, 2021. Management is currently evaluating the impact of these changes on the Consolidated Financial Statements.

In November 2019, the FASB issued ASU No. 2019-08, Compensation—Stock Compensation (Topic 718) and Revenue from Contracts with Customers (Topic 606). In June 2018, the FASB issued ASU No. 2018-07, Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting. ASU 2018-07 effectively changed the accounting for nonemployee share-based payment transactions to be consistent with the accounting for employee share-based payments but did not provide guidance on measuring share-based payment awards granted to a customer. The amendments in ASU No. 2019-08 clarify that an entity must measure and classify share-based payment awards granted to a customer by applying the guidance in Topic 718. The Company adopted ASU No. 2018-07 effective January 1, 2019, and as such, ASU No. 2019-08 will be effective for the Company on January 1, 2020. The adoption of this guidance will not have a material impact on the Company’s Consolidated Financial Statements as the Company does not utilize share-based payments for customers.

In August 2018, the FASB issued separate guidance regarding the respective disclosure requirements associated with fair value measurements and defined benefit plans. This guidance makes changes to the disclosures of fair value measurements and defined benefit plans through several removals, modifications, additions, and/or clarifications of the existing requirements. The following are the changes that will have an immediate disclosure impact for Alcoa upon adoption of the guidance for fair value measurements: (i) disclosure of the valuation processes for Level 3 fair value measurements is no longer required, (ii) changes in unrealized gains and losses for the reporting period included in other comprehensive income (loss) for recurring Level 3 fair value measurements held at the end of the reporting period is a new disclosure requirement, and (iii) the range and weighted average (or other reasonable and rational method) of significant unobservable inputs used to develop Level 3 fair value measurements is a new disclosure requirement. The following are the changes that will have an immediate disclosure impact for the Company upon adoption of the guidance for defined benefit plans: (i) disclosure of the amounts in accumulated other comprehensive income (loss) expected to be recognized as components of net periodic benefit cost over the next fiscal year is no longer required, (ii) disclosure of the effects of a one-percentage-point change in assumed health care cost trend rates on both the aggregate of the service and interest cost components of net periodic benefit costs and the benefit obligation for postretirement health care benefits is no longer required, and (iii) an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the reporting period is a new disclosure requirement. The guidance for fair value measurements and defined benefit plans becomes effective for the Company on January 1, 2020 and December 31, 2020, respectively, with early adoption permitted. Other than updating the applicable disclosures, the adoption of this guidance will not have an impact on the Company’s Consolidated Financial Statements.

In August 2018, the FASB issued ASU No. 2018-15, Intangibles – Goodwill and Other – Internal-Use Software. This ASU aligns the accounting for cloud computing implementation costs with that of costs to develop or obtain internal-use software, meaning such costs that are part of the application development stage are capitalized as an asset and amortized over the term of the arrangement, otherwise, such costs are expensed as incurred. It also clarifies the classification of amounts related to capitalized implementation costs in the financial statements. This guidance becomes effective for the Company on January 1, 2020, with early adoption permitted. Management has completed our assessment of the impact related to this guidance and concluded that the adoption of this guidance will not have a material impact on the Company’s Consolidated Financial Statements.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses. This ASU added a new impairment model (known as the current expected credit loss (CECL) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes an allowance for its estimate of expected credit losses and applies to most debt instruments, trade receivables, lease receivables, financial guarantee contracts, and other loan commitments. The CECL

model does not have a minimum threshold for recognition of impairment losses and entities will need to measure expected credit losses on assets that have a low risk of loss. These changes become effective for the Company on January 1, 2020. Management has completed our assessment of the impact related to this guidance and concluded that the adoption of this guidance will not have a material impact on the Company’s Consolidated Financial Statements.