Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation and Reporting The consolidated financial statements include the accounts of Allegheny Technologies Incorporated and its subsidiaries. The financial results of majority-owned joint ventures are consolidated into the Company’s operating results and financial position, with the minority ownership interest recognized in the consolidated statement of operations as net income attributable to noncontrolling interests, and as equity attributable to the noncontrolling interests within total stockholders’ equity. Investments in which the Company exercises significant influence, but which it does not control (generally a 20% to 50% ownership interest) are accounted for under the equity method of accounting, whereby ATI’s carrying value of the equity method investment on the statement of financial position is the capital investment and any undistributed profit or loss, and is classified in Other (noncurrent) assets. The profit or loss attributable to ATI from equity method investments is included in the consolidated statements of operations as a component of Other (non-operating) income (expense). See Note 9 for further explanation of the Company’s joint ventures. Intercompany accounts and transactions have been eliminated. Unless the context requires otherwise, “Allegheny Technologies,” “ATI” and the “Company” refer to Allegheny Technologies Incorporated and its subsidiaries. Effective January 1, 2020, the Company began operating under two revised business segments: High Performance Materials & Components (HPMC) and Advanced Alloys & Solutions (AA&S). HPMC is now comprised of the Specialty Materials and Forged Products businesses, as well as the ATI Europe distribution operations. The new AA&S segment combines the Specialty Alloys & Components (SAC) business, including the primary titanium operations in Richland, WA and Albany, OR, with ATI’s former Flat Rolled Products (FRP) business segment, which included the FRP business, consisting of the Specialty Rolled Products and Standard Stainless Sheet Products product lines, and the 60%-owned Shanghai STAL Precision Stainless Steel Company Limited (STAL), as well as the Uniti LLC (Uniti) and Allegheny & Tsingshan Stainless (A&T Stainless) 50%-owned joint ventures that are reported in AA&S segment results under the equity method of accounting. See Note 2, Business Segments, for further information. Financial results of aerospace-grade titanium plate products also transferred from HPMC to AA&S effective January 1, 2020. Risks and Uncertainties and Use of Estimates The preparation of consolidated financial statements in conformity with United States generally accepted accounting principles requires management to make estimates and assumptions that affect reported amounts of assets and liabilities at the date of the financial statements, as well as the reported amounts of income and expenses during the reporting period. Actual results could differ from those estimates. Management believes that the estimates are reasonable. Certain prior year amounts have been reclassified in order to conform with the 2020 presentation. The Company markets its products to a diverse customer base, principally throughout the United States. No single customer accounted for more than 10% of sales for any year presented. The major end markets for the ATI’s products are customers in the aerospace & defense, energy, automotive, construction and mining, food equipment and appliances, and medical markets. At December 31, 2020, ATI has approximately 6,500 active employees, of which approximately 20% are located outside the United States. Approximately 40% of ATI’s workforce is covered by various collective bargaining agreements (CBAs), predominantly with the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied & Industrial Service Workers International Union, AFL-CIO, CLC (USW). The Company’s CBA with the USW involving approximately 1,100 active full-time represented employees located primarily within the AA&S segment operations expired on February 29, 2020. On March 25, 2020, the Company announced an agreement with the USW that extended the terms of the expired CBAs for one year, to February 28, 2021. Cash and Cash Equivalents Cash equivalents are highly liquid investments that are readily convertible to cash with original maturities of three months or less. Accounts Receivable Accounts receivable are presented net of a reserve for doubtful accounts of $4.3 million and $4.6 million at December 31, 2020 and 2019, respectively. Trade credit is extended based upon evaluations of each customer’s ability to perform its obligations, which are updated periodically. The Company adopted new accounting guidance in fiscal year 2020 which requires accounts receivable reserves to be determined based on expected credit losses rather than incurred losses, as further discussed below in the section on New Accounting Pronouncements Adopted. Prior to the adoption of this new accounting guidance, account receivable reserves were determined based upon an aging of accounts and a review for collectability of specific accounts. Amounts are written-off against the reserve in the period it is determined that the receivable is uncollectible. Inventories Inventories are stated at the lower of cost (last-in, first-out (LIFO), first-in, first-out (FIFO), and average cost methods) or market. Costs include direct material, direct labor and applicable manufacturing and engineering overhead, and other direct costs. Most of the Company’s inventory is valued utilizing the LIFO costing methodology. Inventory of the Company’s non-U.S. operations is valued using average cost or FIFO methods. The Company evaluates product lines on a quarterly basis to identify inventory carrying values that exceed estimated net realizable value. In applying the lower of cost or market principle, market means current replacement cost, subject to a ceiling (market value shall not exceed net realizable value) and a floor (market shall not be less than net realizable value reduced by an allowance for a normal profit margin). The calculation of a resulting reserve, if any, is recognized as an expense in the period that the need for the reserve is identified. However, in cases where inventory at FIFO cost is lower than the LIFO carrying value, a write-down of the inventory to market may be required, subject to the ceiling and floor. It is the Company’s general policy to write-down to scrap value any inventory that is identified as slow-moving or aged more than twelve months, subject to sales, backlog and anticipated orders considerations. In some instances this aging criterion is up to twenty-four months. Inventory valuation reserves also include amounts pertaining to intercompany profit elimination between different subsidiaries. Long-Lived Assets Property, plant and equipment are recorded at cost, including capitalized interest, and include long-lived assets acquired under finance leases. Depreciation is primarily recorded using the straight-line method. Prior to December 2020, property, plant and equipment associated with the Hot-Rolling and Processing Facility (HRPF) in the AA&S segment was being depreciated utilizing the units of production method of depreciation, which the Company believed provided a better matching of costs and revenues. However, based on changed business conditions resulting from the decision to exit production of standard stainless sheet products and the recognition of an impairment charge on the property, plant and equipment associated with the HRPF in December 2020 (see Note 3 for further discussion), depreciation of the remaining carrying value of the HRPF now uses the straight-line method. The Company periodically reviews estimates of useful life and production capacity assigned to new and in service assets. Significant enhancements, including major maintenance activities that extend the lives of property and equipment, are capitalized. Costs related to repairs and maintenance are charged to expense in the period incurred. The cost and related accumulated depreciation of property and equipment retired or disposed of are removed from the accounts and any related gains or losses are included in income. The Company monitors the recoverability of the carrying value of its long-lived assets. An impairment charge is recognized when an indicator of impairment occurs and the expected net undiscounted future cash flows from an asset’s use (including any proceeds from disposition) are less than the asset’s carrying value and the asset’s carrying value exceeds its fair value. If an impairment loss is recognized, the adjusted carrying value of the long-lived asset is its new cost basis and this new cost basis is depreciated over the remaining useful life of the asset. Assets to be disposed of by sale are stated at the lower of their fair values or carrying amounts and depreciation is no longer recognized. Leases The following is the Company’s accounting policy as it relates to Accounting Standards Codification Topic 842 (ASC 842), Leases. This guidance requires a lessee to recognize assets and liabilities on the balance sheet for all leases, with the result being the recognition of a right of use (ROU) asset and a lease liability. The lease liability is equal to the present value of the minimum lease payments for the term of the lease, including any optional renewal periods determined to be reasonably certain to be exercised, using the discount rate determined at lease commencement. This discount rate is the rate implicit in the lease, if known; otherwise, the incremental borrowing rate (IBR) for the expected lease term is used. The Company’s IBRs approximate the rate the Company would have to pay to borrow on a collateralized basis over a similar term at lease inception. The ROU asset is equal to the initial measurement of the lease liability plus any lease payments made to the lessor at or before the commencement date and any unamortized initial direct costs incurred by the lessee, less any unamortized lease incentives received. The Company has lease contracts for real property and machinery and equipment, primarily for mobile, office and information technology equipment. At inception of a contract, the Company determines whether the contract is or contains a lease. If the Company has a right to obtain substantially all of the economic benefits from the use of the identified asset and the right to direct the use of the asset, then the contract contains a lease. Several of the Company’s real property lease contracts include options to extend the lease term, and the Company reassesses the likelihood of renewal on at least an annual basis. In addition, several real property leases include variable lease payments, for items such as common area maintenance and utilities, which are expensed as incurred as variable lease expense. There are two types of leases: operating leases and finance leases. Lease classification is determined at lease commencement. The criteria used for a lease to be classified as a finance lease is generally consistent with the criteria under the previous lease accounting guidance, ASC 840, for capital leases. All other leases not meeting the finance lease criteria are classified as operating leases. Operating lease expense is recognized on a straight-line basis on the consolidated statement of operations. Finance leases have front-loaded expense recognition which is reported as amortization expense and interest expense on the consolidated statement of operations. ROU assets for operating leases are classified in other long-term assets, and ROU assets for finance leases are classified in property, plant and equipment on the consolidated balance sheet. For operating leases, short-term lease liabilities are classified in other current liabilities, and long-term lease liabilities are classified in other long-term liabilities on the consolidated balance sheet. For finance leases, short-term lease liabilities are classified in short-term debt, and long-term lease liabilities are classified in long-term debt on the consolidated balance sheet. On the cash flow statement, payments for operating leases are classified as operating activities. Payments for finance leases are classified as a financing activity, with the exception of the interest component of the payment which is classified as an operating activity. Goodwill Goodwill is reviewed annually for impairment, or more frequently if impairment indicators arise. The review for goodwill impairment requires a comparison of the fair value of each reporting unit that has goodwill associated with its operations with its carrying amount, including goodwill. If this comparison reflects impairment, then the loss would be measured as the excess of the carrying value over the calculated fair value. Generally accepted accounting standards provide the option to qualitatively assess goodwill for impairment before completing a quantitative assessment. Under the qualitative approach, if, after assessing the totality of events or circumstances, including both macroeconomic, industry and market factors, and entity-specific factors, the Company determines it is likely (more likely than not) that the fair value of a reporting unit is greater than its carrying amount, then the quantitative impairment analysis is not required. The quantitative assessment may be performed each year for a reporting unit at the Company’s option without first performing a qualitative assessment. The Company’s quantitative assessment of goodwill for possible impairment includes estimating the fair market value of a reporting unit which has goodwill associated with its operations using discounted cash flow and multiples of cash earnings valuation techniques, plus valuation comparisons to recent public sale transactions of similar businesses, if any. These impairment assessments and valuation methods require the Company to make estimates and assumptions regarding future operating results, cash flows, changes in working capital and capital expenditures, selling prices, profitability, and the cost of capital. Many of these assumptions are determined by reference to market participants identified by the Company. Although management believes that the estimates and assumptions used were reasonable, actual results could differ from those estimates and assumptions. Other events and changes in circumstances may also require goodwill to be tested for impairment between annual measurement dates. While a decline in stock price and market capitalization is not specifically cited as a goodwill impairment indicator, a company’s stock price and market capitalization should be considered in determining whether it is more likely than not that the fair value of a reporting unit is less that its carrying value. Additionally, a significant decline in a company’s stock price may suggest that an adverse change in the business climate may have caused the fair value of one or more reporting units to fall below carrying value. A sustained decline in market capitalization below book value may be determined to require an interim goodwill impairment review. Environmental Costs that mitigate or prevent future environmental contamination or extend the life, increase the capacity or improve the safety or efficiency of property utilized in current operations are capitalized. Other costs that relate to current operations or an existing condition caused by past operations are expensed. Environmental liabilities are recorded when the Company’s liability is probable and the costs are reasonably estimable, but generally not later than the completion of the feasibility study or the Company’s recommendation of a remedy or commitment to an appropriate plan of action. The accruals are reviewed periodically and, as investigations and remediations proceed, adjustments of the accruals are made to reflect new information as appropriate. Accruals for losses from environmental remediation obligations do not take into account the effects of inflation, and anticipated expenditures are not discounted to their present value. The accruals are not reduced by possible recoveries from insurance carriers or other third parties, but do reflect allocations among potentially responsible parties (PRPs) at Federal Superfund sites or similar state-managed sites after an assessment is made of the likelihood that such parties will fulfill their obligations at such sites and after appropriate cost-sharing or other agreements are entered. The measurement of environmental liabilities by the Company is based on currently available facts, present laws and regulations, and current technology. Such estimates take into consideration the Company’s prior experience in site investigation and remediation, the data concerning cleanup costs available from other companies and regulatory authorities, and the professional judgment of the Company’s environmental experts in consultation with outside environmental specialists, when necessary. Foreign Currency Translation Assets and liabilities of international operations are translated into U.S. dollars using year-end exchange rates, while revenues and expenses are translated at average exchange rates during the period. The resulting net translation adjustments are recorded as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Sales Recognition The following is the Company’s accounting policy as it relates to Accounting Standards Codification Topic 606 (ASC 606), Revenue from Customers. This guidance provides a five-step analysis of transactions to determine when and how revenue is recognized, and requires an entity to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The following is the Company’s accounting policy as it relates to the five-step analysis for revenue recognition: 1.Identify the contract: The Company has determined that the contract with the customer is established when the customer purchase order is accepted or acknowledged. Long-term agreements (LTAs), which typically extend multiple years, are used by the Company and certain of its customers for its specialty materials, in the form of mill products, powders, parts and components, to reduce their supply uncertainty. While these LTAs generally define commercial terms including pricing, termination clauses and other contractual requirements, they do not represent the contract with the customer. 2.Identify the performance obligation in the contract: When the Company accepts or acknowledges the customer purchase order, the type of good or service is defined on a line by line basis. Individual performance obligations are established by virtue of the individual line items identified on the sales order acknowledgment at the time of issuance. Generally, the Company’s revenue relates to the sale of goods and contains a single performance obligation for each distinct good. Conversion services that transform customer-owned inventory to a different dimension, product form, and/or changed mechanical properties are classified as “goods”. 3.Determine the transaction price: Pricing is also defined on a sales order acknowledgment on a line item basis and includes an estimate of variable consideration when required by the terms of the individual customer contract. Variable consideration is when the selling price of the good is not known or is subject to adjustment under certain conditions. Types of variable consideration may include volume discounts, customer rebates and surcharges. ATI also provides assurances that goods or services will meet the product specifications contained within the acknowledged customer contract. As such, returns and refunds reserves are estimated based upon past product line history or, at certain locations, on a claim by claim basis. 4.Allocate the transaction price to the performance obligation: Since a customer contract generally contains only one performance obligation, this step of the analysis is generally not applicable to the Company. 5.Recognize revenue when or as the performance obligation is satisfied: Performance obligations generally occur at a point in time and are satisfied when control passes to the customer. For most transactions, control passes at the time of shipment in accordance with agreed upon delivery terms. On occasion, shipping and handling charges occur after the customer obtains control of the good. When this occurs, the shipping and handling services are considered activities to fulfill the promise to transfer the good. Certain customer agreements involving production of parts and components require revenue to be recognized over time due to there being no alternative use for the product without significant economic loss and an enforceable right to payment including a normal profit margin from the customer in the event of contract termination. The Company uses an input method for determining the amount of revenue, and associated standard cost, to recognize over-time revenue, cost and gross margin for these customer agreements. The input methods used for these agreements include costs incurred and labor hours expended, both of which give an accurate representation of the progress made toward complete satisfaction of that particular performance obligation. Contract assets are recognized when ATI’s conditional right to consideration for goods or services have transferred to the customer. A conditional right indicates that additional performance obligations associated with the contract are yet to be satisfied. Contract assets are assessed separately for impairment purposes. If ATI’s right to consideration from the customer is unconditional, this asset is accounted for as a receivable and presented separately from other contract assets. A right is unconditional if nothing other than the passage of time is required before payment of that consideration is due. Performance obligations that are recognized as revenue at a point-in-time and are billed to the customer are recognized as accounts receivable. Payment terms vary from customer to customer depending upon credit worthiness, prior payment history and other credit considerations. Contract costs are the incremental costs of obtaining and fulfilling a contract (i.e., costs that would not have been incurred if the contract had not been obtained) to provide goods and services to customers. Contract costs for ATI largely consist of design and development costs for molds, dies and other tools that ATI will own and that will be used in producing the products under the supply arrangement. Contract costs are classified as non-current assets and amortized to expense on a systematic and rational basis over a period consistent with the transfer to the customer of the goods or services to which the asset relates. Contract liabilities are recognized when ATI has received consideration from a customer to transfer goods or services at a future point in time when the Company performs under the contract. Elements of variable consideration discussed above may be recorded as contract liabilities. In addition, progress billings and advance payments from customers for costs incurred to date are also reported as contract liabilities. Research and Development Our research, development and technical service activities are closely interrelated and are directed toward development of new products, improvement of existing products, cost reduction, process improvement and control, quality assurance and control, development of new manufacturing methods, and improvement of existing manufacturing methods. Research and development costs are expensed as incurred. Company funded research and development costs were $14.1 million in 2020, $17.8 million in 2019, and $22.7 million in 2018. Customer funded research and development costs were $0.7 million in 2020, $2.4 million in 2019, and $2.2 million in 2018. Stock-based Compensation The Company accounts for stock-based compensation transactions, such as nonvested restricted stock or stock units and performance equity awards, using fair value. Compensation expense for an award is estimated at the date of grant and is recognized over the requisite service period. Compensation expense is adjusted for equity awards that do not vest because service or performance conditions are not satisfied. However, compensation expense already recognized on plans which vest based solely on the attainment of market conditions, such as total shareholder return measures, is not adjusted based on the award attainment status at the end of the measurement period. Compensation expense is adjusted for estimated forfeitures over the award measurement period. Income Taxes The provision for, or benefit from, income taxes includes deferred taxes resulting from temporary differences in income for financial and tax purposes using the liability method. Such temporary differences result primarily from differences in the carrying value of assets and liabilities. Future realization of deferred income tax assets requires sufficient taxable income within the carryback and/or carryforward period available under tax law. The Company evaluates on a quarterly basis whether, based on all available evidence, it is probable that the deferred income tax assets are realizable. Valuation allowances are established when it is estimated that it is more likely than not that the tax benefit of the deferred tax asset will not be realized. The evaluation includes the consideration of all available evidence, both positive and negative, regarding the estimated future reversals of existing taxable temporary differences, estimated future taxable income exclusive of reversing temporary differences and carryforwards, historical taxable income in prior carryback periods if carryback is permitted, and potential tax planning strategies which may be employed to prevent an operating loss or tax credit carryforward from expiring unused. The verifiable evidence such as future reversals of existing temporary differences and the ability to carryback are considered before the subjective sources such as estimate future taxable income exclusive of temporary differences and tax planning strategies. It is the Company’s policy to classify interest and penalties recognized on underpayment of income taxes as income tax expense. It is also the Company’s policy to recognize deferred tax amounts stranded in accumulated other comprehensive income (AOCI), which result from tax rate differences on changes in AOCI balances, as an element of income tax expense in the period that the related balance sheet item associated with the AOCI balance ceases to exist. In the case of derivative financial instruments accounted for as hedges, or marketable securities, ATI uses the portfolio method where the stranded deferred tax amount is recognized when all items of a particular category, such as cash flow hedges of a particular risk such as a foreign currency hedge, are settled. In the case of defined benefit pension and other postretirement benefit plans, the stranded deferred tax balance is recognized as an element of income tax expense in the period the benefit plan is extinguished. Net Income Per Common Share Basic and diluted net income per share are calculated by dividing the net income available to common stockholders by the weighted average number of common shares outstanding during the year. Diluted amounts assume the issuance of common stock for all potentially dilutive share equivalents outstanding. The calculations of all diluted income/loss per share figures for a period exclude the potentially dilutive effect of dilutive share equivalents if there is a net loss since the inclusion in the calculation of additional shares in the net loss per share would result in a lower per share loss and therefore be anti-dilutive. New Accounting Pronouncements Adopted In March 2020, the Financial Accounting Standards Board (FASB) issued new optional accounting guidance 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. In response to concerns about structural risks of interbank offered rates, and, particularly, the risk of cessation of the London Interbank Offered Rate (LIBOR), regulators in several jurisdictions around the world have undertaken reference rate reform initiatives to identify alternative reference rates that are more observable or transaction based and less susceptible to manipulation. The new accounting guidance provides optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The new accounting guidance applies only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments generally do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022. Management is continuing to evaluate the issue, and presently does not expect a transition away from LIBOR, primarily involving ATI’s domestic credit facility and an interest rate swap contract, to have any significant financial impact to ATI. In December 2019, the FASB issued new guidance to simplify the accounting for income taxes. The areas for simplification in the guidance involve the removal of certain exceptions to the general principles in the current guidance, including intraperiod allocation and the calculation of income taxes in an interim period when a year to date loss exceeds the anticipated loss for the year. The new guidance also simplifies the accounting for income taxes in the area of franchise taxes. This new guidance is effective for the Company in fiscal year 2021, with early adoption permitted. This guidance was early adopted by the Company in fiscal year 2020 without significant impact to the consolidated financial statements. In August 2018, the FASB issued new disclosure guidance on fair value measurement. This new guidance modifies the disclosure requirements on fair value measurements, including removal and modifications of various current disclosures as well as some additional disclosure requirements for Level 3 fair value measurements. Some of these disclosure changes must be applied prospectively while others retrospectively depending on the requirement. This guidance was adopted by the Company in fiscal year 2020 without an impact on the Company’s consolidated financial statements other than disclosures. In June 2016, the FASB 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 as an allowance its estimate of expected credit losses. The CECL model applies to trade receivables, other receivables, contract assets and most debt instruments. 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. This guidance was adopted by the Company in fiscal year 2020 without significant impact to the consolidated financial statements. Pending Accounting Pronouncements In August 2020, the FASB issued new accounting guidance related to accounting for convertible instruments. Under this new guidance, embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives, or that do not result in substantial premiums accounted for as paid-in capital. As such, a convertible debt instrument will be accounted for as a single liability measured at its amortized cost, as long as no other features require bifurcation and recognition as derivatives. By removing those separation models, the reported interest rate of convertible debt instruments typically will be closer to the coupon interest rate. The new guidance also addresses how convertible instruments are accounted for in the diluted earnings per share calculation, requiring the if-converted method, and requires enhanced disclosures about the terms of convertible instruments and contracts in an entity’s own equity. This new guidance is effective for the Company in fiscal year 2022, with early adoption permitted. The Company adopted this new accounting guidance related to accounting for convertible instruments effective January 1, 2021 using the modified transition approach with the cumulative effect recognized as an adjustment to the opening balance of retained earnings. This new guidance is applicable to the Company’s 3.5% Convertible Senior Notes due 2025 (the 2025 Convertible Notes) that were issued in June 2020, for which the embedded conversion option was required to be separately accounted for as a component of stockholders’ equity. Upon adoption on January 1, 2021, long-term debt increased by $45.4 million and stockholders’ equity decreased by the same amount, representing the net impact of two adjustments: (1) the $49.8 million value of the embedded conversion, which is net of allocated offering costs, previously classified in additional paid-in-capital in stockholders’ equity, and (2) a $4.4 million increase to retained earnings for the cumulative effect of adoption primarily related to the non-cash interest expense recorded in fiscal year 2020 for the amortization of the portion of the 2025 Convertible Notes allocated to stockholders’ equity. Prospectively, the reported interest expense for the 2025 Convertible Notes will no longer include the non-cash interest expense of the equity component as required under prior accounting standards and will be closer to the 3.5% cash coupon rate. There will be no impact to the Company’s earnings per share calculation as it previously applied the if-converted method to the 2025 Convertible Notes given ATI’s flexibility to settle conversions of the 2025 Convertible Notes in cash, shares of ATI’s common stock or a combination thereof, at ATI’s election.

The consolidated financial statements include the accounts of Allegheny Technologies Incorporated and its subsidiaries. The financial results of majority-owned joint ventures are consolidated into the Company’s operating results and financial position, with the minority ownership interest recognized in the consolidated statement of operations as net income attributable to noncontrolling interests, and as equity attributable to the noncontrolling interests within total stockholders’ equity. Investments in which the Company exercises significant influence, but which it does not control (generally a 20% to 50% ownership interest) are accounted for under the equity method of accounting, whereby ATI’s carrying value of the equity method investment on the statement of financial position is the capital investment and any undistributed profit or loss, and is classified in Other (noncurrent) assets. The profit or loss attributable to ATI from equity method investments is included in the consolidated statements of operations as a component of Other (non-operating) income (expense). See Note 9 for further explanation of the Company’s joint ventures. Intercompany accounts and transactions have been eliminated. Unless the context requires otherwise, “Allegheny Technologies,” “ATI” and the “Company” refer to Allegheny Technologies Incorporated and its subsidiaries.

Effective January 1, 2020, the Company began operating under two revised business segments: High Performance Materials & Components (HPMC) and Advanced Alloys & Solutions (AA&S). HPMC is now comprised of the Specialty Materials and Forged Products businesses, as well as the ATI Europe distribution operations. The new AA&S segment combines the Specialty Alloys & Components (SAC) business, including the primary titanium operations in Richland, WA and Albany, OR, with ATI’s former Flat Rolled Products (FRP) business segment, which included the FRP business, consisting of the Specialty Rolled Products and Standard Stainless Sheet Products product lines, and the 60%-owned Shanghai STAL Precision Stainless Steel Company Limited (STAL), as well as the Uniti LLC (Uniti) and Allegheny & Tsingshan Stainless (A&T Stainless) 50%-owned joint ventures that are reported in AA&S segment results under the equity method of accounting. See Note 2, Business Segments, for further information. Financial results of aerospace-grade titanium plate products also transferred from HPMC to AA&S effective January 1, 2020.

The preparation of consolidated financial statements in conformity with United States generally accepted accounting principles requires management to make estimates and assumptions that affect reported amounts of assets and liabilities at the date of the financial statements, as well as the reported amounts of income and expenses during the reporting period. Actual results could differ from those estimates. Management believes that the estimates are reasonable. Certain prior year amounts have been reclassified in order to conform with the 2020 presentation.

The Company markets its products to a diverse customer base, principally throughout the United States. No single customer accounted for more than 10% of sales for any year presented. The major end markets for the ATI’s products are customers in the aerospace & defense, energy, automotive, construction and mining, food equipment and appliances, and medical markets.

At December 31, 2020, ATI has approximately 6,500 active employees, of which approximately 20% are located outside the United States. Approximately 40% of ATI’s workforce is covered by various collective bargaining agreements (CBAs), predominantly with the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied & Industrial Service Workers International Union, AFL-CIO, CLC (USW). The Company’s CBA with the USW involving approximately 1,100 active full-time represented employees located primarily within the AA&S segment operations expired on February 29, 2020. On March 25, 2020, the Company announced an agreement with the USW that extended the terms of the expired CBAs for one year, to February 28, 2021.

Accounts receivable are presented net of a reserve for doubtful accounts of $4.3 million and $4.6 million at December 31, 2020 and 2019, respectively. Trade credit is extended based upon evaluations of each customer’s ability to perform its obligations, which are updated periodically. The Company adopted new accounting guidance in fiscal year 2020 which requires accounts receivable reserves to be determined based on expected credit losses rather than incurred losses, as further discussed below in the section on New Accounting Pronouncements Adopted. Prior to the adoption of this new accounting guidance, account receivable reserves were determined based upon an aging of accounts and a review for collectability of specific accounts. Amounts are written-off against the reserve in the period it is determined that the receivable is uncollectible.

Inventories are stated at the lower of cost (last-in, first-out (LIFO), first-in, first-out (FIFO), and average cost methods) or market. Costs include direct material, direct labor and applicable manufacturing and engineering overhead, and other direct costs. Most of the Company’s inventory is valued utilizing the LIFO costing methodology. Inventory of the Company’s non-U.S. operations is valued using average cost or FIFO methods.

The Company evaluates product lines on a quarterly basis to identify inventory carrying values that exceed estimated net realizable value. In applying the lower of cost or market principle, market means current replacement cost, subject to a ceiling (market value shall not exceed net realizable value) and a floor (market shall not be less than net realizable value reduced by an allowance for a normal profit margin). The calculation of a resulting reserve, if any, is recognized as an expense in the period that the need for the reserve is identified. However, in cases where inventory at FIFO cost is lower than the LIFO carrying value, a write-down of the inventory to market may be required, subject to the ceiling and floor. It is the Company’s general policy to write-down to scrap value any inventory that is identified as slow-moving or aged more than twelve months, subject to sales, backlog and anticipated orders considerations. In some instances this aging criterion is up to twenty-four months. Inventory valuation reserves also include amounts pertaining to intercompany profit elimination between different subsidiaries.

Property, plant and equipment are recorded at cost, including capitalized interest, and include long-lived assets acquired under finance leases. Depreciation is primarily recorded using the straight-line method. Prior to December 2020, property, plant and equipment associated with the Hot-Rolling and Processing Facility (HRPF) in the AA&S segment was being depreciated utilizing the units of production method of depreciation, which the Company believed provided a better matching of costs and revenues. However, based on changed business conditions resulting from the decision to exit production of standard stainless sheet products and the recognition of an impairment charge on the property, plant and equipment associated with the HRPF in December 2020 (see Note 3 for further discussion), depreciation of the remaining carrying value of the HRPF now uses the straight-line method. The Company periodically reviews estimates of useful life and production capacity assigned to new and in service assets. Significant enhancements, including major maintenance activities that extend the lives of property and equipment, are capitalized. Costs related to repairs and maintenance are charged to expense in the period incurred. The cost and related accumulated depreciation of property and equipment retired or disposed of are removed from the accounts and any related gains or losses are included in income.

The Company monitors the recoverability of the carrying value of its long-lived assets. An impairment charge is recognized when an indicator of impairment occurs and the expected net undiscounted future cash flows from an asset’s use (including any proceeds from disposition) are less than the asset’s carrying value and the asset’s carrying value exceeds its fair value. If an impairment loss is recognized, the adjusted carrying value of the long-lived asset is its new cost basis and this new cost basis is depreciated over the remaining useful life of the asset. Assets to be disposed of by sale are stated at the lower of their fair values or carrying amounts and depreciation is no longer recognized.

The following is the Company’s accounting policy as it relates to Accounting Standards Codification Topic 842 (ASC 842), Leases. This guidance requires a lessee to recognize assets and liabilities on the balance sheet for all leases, with the result being the recognition of a right of use (ROU) asset and a lease liability. The lease liability is equal to the present value of the minimum lease payments for the term of the lease, including any optional renewal periods determined to be reasonably certain to be exercised, using the discount rate determined at lease commencement. This discount rate is the rate implicit in the lease, if known; otherwise, the incremental borrowing rate (IBR) for the expected lease term is used. The Company’s IBRs approximate the rate the Company would have to pay to borrow on a collateralized basis over a similar term at lease inception. The ROU asset is equal to the initial measurement of the lease liability plus any lease payments made to the lessor at or before the commencement date and any unamortized initial direct costs incurred by the lessee, less any unamortized lease incentives received.

The Company has lease contracts for real property and machinery and equipment, primarily for mobile, office and information technology equipment. At inception of a contract, the Company determines whether the contract is or contains a lease. If the Company has a right to obtain substantially all of the economic benefits from the use of the identified asset and the right to direct the use of the asset, then the contract contains a lease. Several of the Company’s real property lease contracts include options to extend the lease term, and the Company reassesses the likelihood of renewal on at least an annual basis. In addition, several real property leases include variable lease payments, for items such as common area maintenance and utilities, which are expensed as incurred as variable lease expense.

There are two types of leases: operating leases and finance leases. Lease classification is determined at lease commencement. The criteria used for a lease to be classified as a finance lease is generally consistent with the criteria under the previous lease accounting guidance, ASC 840, for capital leases. All other leases not meeting the finance lease criteria are classified as operating leases. Operating lease expense is recognized on a straight-line basis on the consolidated statement of operations. Finance leases have front-loaded expense recognition which is reported as amortization expense and interest expense on the consolidated statement of operations. ROU assets for operating leases are classified in other long-term assets, and ROU assets for finance leases are classified in property, plant and equipment on the consolidated balance sheet. For operating leases, short-term lease liabilities are classified in other current liabilities, and long-term lease liabilities are classified in other long-term liabilities on the consolidated balance sheet. For finance leases, short-term lease liabilities are classified in short-term debt, and long-term lease liabilities are classified in long-term debt on the consolidated balance sheet. On the cash flow statement, payments for operating leases are classified as operating activities. Payments for finance leases are classified as a financing activity, with the exception of the interest component of the payment which is classified as an operating activity.

Goodwill is reviewed annually for impairment, or more frequently if impairment indicators arise. The review for goodwill impairment requires a comparison of the fair value of each reporting unit that has goodwill associated with its operations with its carrying amount, including goodwill. If this comparison reflects impairment, then the loss would be measured as the excess of the carrying value over the calculated fair value.

Generally accepted accounting standards provide the option to qualitatively assess goodwill for impairment before completing a quantitative assessment. Under the qualitative approach, if, after assessing the totality of events or circumstances, including both macroeconomic, industry and market factors, and entity-specific factors, the Company determines it is likely (more likely than not) that the fair value of a reporting unit is greater than its carrying amount, then the quantitative impairment analysis is not required. The quantitative assessment may be performed each year for a reporting unit at the Company’s option without first performing a qualitative assessment. The Company’s quantitative assessment of goodwill for possible impairment includes estimating the fair market value of a reporting unit which has goodwill associated with its operations using discounted cash flow and multiples of cash earnings valuation techniques, plus valuation comparisons to recent public sale transactions of similar businesses, if any. These impairment assessments and valuation methods require the Company to make estimates and assumptions regarding future operating results, cash flows, changes in working capital and capital expenditures, selling prices, profitability, and the cost of capital. Many of these assumptions are determined by reference to market participants identified by the Company. Although management believes that the estimates and assumptions used were reasonable, actual results could differ from those estimates and assumptions.

Other events and changes in circumstances may also require goodwill to be tested for impairment between annual measurement dates. While a decline in stock price and market capitalization is not specifically cited as a goodwill impairment indicator, a company’s stock price and market capitalization should be considered in determining whether it is more likely than not that the fair value of a reporting unit is less that its carrying value. Additionally, a significant decline in a company’s stock price may suggest that an adverse change in the business climate may have caused the fair value of one or more reporting units to fall below carrying value. A sustained decline in market capitalization below book value may be determined to require an interim goodwill impairment review.

Costs that mitigate or prevent future environmental contamination or extend the life, increase the capacity or improve the safety or efficiency of property utilized in current operations are capitalized. Other costs that relate to current operations or an existing condition caused by past operations are expensed. Environmental liabilities are recorded when the Company’s liability is probable and the costs are reasonably estimable, but generally not later than the completion of the feasibility study or the Company’s recommendation of a remedy or commitment to an appropriate plan of action. The accruals are reviewed periodically and, as investigations and remediations proceed, adjustments of the accruals are made to reflect new information as appropriate. Accruals for losses from environmental remediation obligations do not take into account the effects of inflation, and anticipated expenditures are not discounted to their present value. The accruals are not reduced by possible recoveries from

insurance carriers or other third parties, but do reflect allocations among potentially responsible parties (PRPs) at Federal Superfund sites or similar state-managed sites after an assessment is made of the likelihood that such parties will fulfill their obligations at such sites and after appropriate cost-sharing or other agreements are entered. The measurement of environmental liabilities by the Company is based on currently available facts, present laws and regulations, and current technology. Such estimates take into consideration the Company’s prior experience in site investigation and remediation, the data concerning cleanup costs available from other companies and regulatory authorities, and the professional judgment of the Company’s environmental experts in consultation with outside environmental specialists, when necessary.

Assets and liabilities of international operations are translated into U.S. dollars using year-end exchange rates, while revenues and expenses are translated at average exchange rates during the period. The resulting net translation adjustments are recorded as a component of accumulated other comprehensive income (loss) in stockholders’ equity.

The following is the Company’s accounting policy as it relates to Accounting Standards Codification Topic 606 (ASC 606), Revenue from Customers. This guidance provides a five-step analysis of transactions to determine when and how revenue is recognized, and requires an entity to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.

1.Identify the contract: The Company has determined that the contract with the customer is established when the customer purchase order is accepted or acknowledged. Long-term agreements (LTAs), which typically extend multiple years, are used by the Company and certain of its customers for its specialty materials, in the form of mill products, powders, parts and components, to reduce their supply uncertainty. While these LTAs generally define commercial terms including pricing, termination clauses and other contractual requirements, they do not represent the contract with the customer.

2.Identify the performance obligation in the contract: When the Company accepts or acknowledges the customer purchase order, the type of good or service is defined on a line by line basis. Individual performance obligations are established by virtue of the individual line items identified on the sales order acknowledgment at the time of issuance. Generally, the Company’s revenue relates to the sale of goods and contains a single performance obligation for each distinct good. Conversion services that transform customer-owned inventory to a different dimension, product form, and/or changed mechanical properties are classified as “goods”.

3.Determine the transaction price: Pricing is also defined on a sales order acknowledgment on a line item basis and includes an estimate of variable consideration when required by the terms of the individual customer contract. Variable consideration is when the selling price of the good is not known or is subject to adjustment under certain conditions. Types of variable consideration may include volume discounts, customer rebates and surcharges. ATI also provides assurances that goods or services will meet the product specifications contained within the acknowledged customer contract. As such, returns and refunds reserves are estimated based upon past product line history or, at certain locations, on a claim by claim basis.

5.Recognize revenue when or as the performance obligation is satisfied: Performance obligations generally occur at a point in time and are satisfied when control passes to the customer. For most transactions, control passes at the time of shipment in accordance with agreed upon delivery terms. On occasion, shipping and handling charges occur after the customer obtains control of the good. When this occurs, the shipping and handling services are considered activities to fulfill the promise to transfer the good.

Certain customer agreements involving production of parts and components require revenue to be recognized over time due to there being no alternative use for the product without significant economic loss and an enforceable right to payment including a normal profit margin from the customer in the event of contract termination. The Company uses an input method for determining the amount of revenue, and associated standard cost, to recognize over-time revenue, cost and gross margin for these customer agreements. The input methods used for these agreements include costs incurred and labor hours expended, both of which give an accurate representation of the progress made toward complete satisfaction of that particular performance obligation.

Contract assets are recognized when ATI’s conditional right to consideration for goods or services have transferred to the customer. A conditional right indicates that additional performance obligations associated with the contract are yet to be satisfied. Contract assets are assessed separately for impairment purposes. If ATI’s right to consideration from the customer is unconditional, this asset is accounted for as a receivable and presented separately from other contract assets. A right is unconditional if nothing other than the passage of time is required before payment of that consideration is due. Performance obligations that are recognized as revenue at a point-in-time and are billed to the customer are recognized as accounts receivable. Payment terms vary from customer to customer depending upon credit worthiness, prior payment history and other credit considerations.

Contract costs are the incremental costs of obtaining and fulfilling a contract (i.e., costs that would not have been incurred if the contract had not been obtained) to provide goods and services to customers. Contract costs for ATI largely consist of design and development costs for molds, dies and other tools that ATI will own and that will be used in producing the products under the supply arrangement. Contract costs are classified as non-current assets and amortized to expense on a systematic and rational basis over a period consistent with the transfer to the customer of the goods or services to which the asset relates.

Contract liabilities are recognized when ATI has received consideration from a customer to transfer goods or services at a future point in time when the Company performs under the contract. Elements of variable consideration discussed above may be recorded as contract liabilities. In addition, progress billings and advance payments from customers for costs incurred to date are also reported as contract liabilities.

Our research, development and technical service activities are closely interrelated and are directed toward development of new products, improvement of existing products, cost reduction, process improvement and control, quality assurance and control, development of new manufacturing methods, and improvement of existing manufacturing methods. Research and development costs are expensed as incurred. Company funded research and development costs were $14.1 million in 2020, $17.8 million in 2019, and $22.7 million in 2018. Customer funded research and development costs were $0.7 million in 2020, $2.4 million in 2019, and $2.2 million in 2018.

The Company accounts for stock-based compensation transactions, such as nonvested restricted stock or stock units and performance equity awards, using fair value. Compensation expense for an award is estimated at the date of grant and is recognized over the requisite service period. Compensation expense is adjusted for equity awards that do not vest because service or performance conditions are not satisfied. However, compensation expense already recognized on plans which vest based solely on the attainment of market conditions, such as total shareholder return measures, is not adjusted based on the award attainment status at the end of the measurement period. Compensation expense is adjusted for estimated forfeitures over the award measurement period.

The provision for, or benefit from, income taxes includes deferred taxes resulting from temporary differences in income for financial and tax purposes using the liability method. Such temporary differences result primarily from differences in the carrying value of assets and liabilities. Future realization of deferred income tax assets requires sufficient taxable income within the carryback and/or carryforward period available under tax law.

The Company evaluates on a quarterly basis whether, based on all available evidence, it is probable that the deferred income tax assets are realizable. Valuation allowances are established when it is estimated that it is more likely than not that the tax benefit of the deferred tax asset will not be realized. The evaluation includes the consideration of all available evidence, both positive and negative, regarding the estimated future reversals of existing taxable temporary differences, estimated future taxable income exclusive of reversing temporary differences and carryforwards, historical taxable income in prior carryback periods if carryback is permitted, and potential tax planning strategies which may be employed to prevent an operating loss or tax credit carryforward from expiring unused. The verifiable evidence such as future reversals of existing temporary differences and the ability to carryback are considered before the subjective sources such as estimate future taxable income exclusive of temporary differences and tax planning strategies.

It is the Company’s policy to classify interest and penalties recognized on underpayment of income taxes as income tax expense. It is also the Company’s policy to recognize deferred tax amounts stranded in accumulated other comprehensive income (AOCI), which result from tax rate differences on changes in AOCI balances, as an element of income tax expense in the period that the related balance sheet item associated with the AOCI balance ceases to exist. In the case of derivative financial instruments accounted for as hedges, or marketable securities, ATI uses the portfolio method where the stranded

deferred tax amount is recognized when all items of a particular category, such as cash flow hedges of a particular risk such as a foreign currency hedge, are settled. In the case of defined benefit pension and other postretirement benefit plans, the stranded deferred tax balance is recognized as an element of income tax expense in the period the benefit plan is extinguished.

Basic and diluted net income per share are calculated by dividing the net income available to common stockholders by the weighted average number of common shares outstanding during the year. Diluted amounts assume the issuance of common stock for all potentially dilutive share equivalents outstanding. The calculations of all diluted income/loss per share figures for a period exclude the potentially dilutive effect of dilutive share equivalents if there is a net loss since the inclusion in the calculation of additional shares in the net loss per share would result in a lower per share loss and therefore be anti-dilutive.

In March 2020, the Financial Accounting Standards Board (FASB) issued new optional accounting guidance 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. In response to concerns about structural risks of interbank offered rates, and, particularly, the risk of cessation of the London Interbank Offered Rate (LIBOR), regulators in several jurisdictions around the world have undertaken reference rate reform initiatives to identify alternative reference rates that are more observable or transaction based and less susceptible to manipulation. The new accounting guidance provides optional expedients and exceptions for applying generally accepted accounting principles to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The new accounting guidance applies only to contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments generally do not apply to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022. Management is continuing to evaluate the issue, and presently does not expect a transition away from LIBOR, primarily involving ATI’s domestic credit facility and an interest rate swap contract, to have any significant financial impact to ATI.

In December 2019, the FASB issued new guidance to simplify the accounting for income taxes. The areas for simplification in the guidance involve the removal of certain exceptions to the general principles in the current guidance, including intraperiod allocation and the calculation of income taxes in an interim period when a year to date loss exceeds the anticipated loss for the year. The new guidance also simplifies the accounting for income taxes in the area of franchise taxes. This new guidance is effective for the Company in fiscal year 2021, with early adoption permitted. This guidance was early adopted by the Company in fiscal year 2020 without significant impact to the consolidated financial statements.

In August 2018, the FASB issued new disclosure guidance on fair value measurement. This new guidance modifies the disclosure requirements on fair value measurements, including removal and modifications of various current disclosures as well as some additional disclosure requirements for Level 3 fair value measurements. Some of these disclosure changes must be applied prospectively while others retrospectively depending on the requirement. This guidance was adopted by the Company in fiscal year 2020 without an impact on the Company’s consolidated financial statements other than disclosures.

In June 2016, the FASB 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 as an allowance its estimate of expected credit losses. The CECL model applies to trade receivables, other receivables, contract assets and most debt instruments. 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. This guidance was adopted by the Company in fiscal year 2020 without significant impact to the consolidated financial statements.

In August 2020, the FASB issued new accounting guidance related to accounting for convertible instruments. Under this new guidance, embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives, or that do not result in substantial premiums accounted for as paid-in capital. As such, a convertible debt instrument will be accounted for as a single liability measured at its amortized cost, as long as no other features require bifurcation and recognition as derivatives. By removing those separation models, the reported interest rate of convertible debt instruments typically will be closer to the coupon interest rate. The new guidance also addresses how convertible instruments are accounted for in the diluted earnings per share calculation, requiring the if-converted method, and requires enhanced disclosures about the terms of convertible instruments and contracts in an entity’s own equity. This new guidance is effective for the Company in fiscal year 2022, with early adoption permitted.