Business, Basis of Presentation and Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation	Principles of ConsolidationThe accompanying consolidated financial statements include MasTec, Inc. and its subsidiaries and include the accounts of all majority owned subsidiaries over which the Company exercises control and, when applicable, entities in which the Company has a controlling financial interest. All significant intercompany balances and transactions have been eliminated in consolidation. Other parties’ interests in entities that MasTec consolidates are reported as non-controlling interests within equity, except for mandatorily redeemable non-controlling interests, which are recorded within liabilities. Net income or loss attributable to non-controlling interests is reported as a separate line item below net income or loss. The Company’s investments in entities for which the Company does not have a controlling interest, but over which it has the ability to exert significant influence, are accounted for using the equity method of accounting. For equity investees in which the Company has an undivided interest in the assets, liabilities and profits or losses of an unincorporated entity, but does not exercise control over the entity, the Company consolidates its proportional interest in the accounts of the entity.
COVID-19 Disclosure	COVID-19 Pandemic The World Health Organization declared a global pandemic related to the rapidly growing outbreak of a novel strain of coronavirus in the first quarter of 2020. The COVID-19 pandemic has disrupted business activities and significantly affected global economic conditions as federal, state and local governments imposed mitigation measures to address the public health crisis, resulting in workforce, supply chain and production disruptions, the effects of which have created significant uncertainties in the U.S. and global economies. Restrictions have been enacted, lifted, and reenacted during 2020 and into 2021, and the possibility of future restrictions remains. Most of the Company’s construction services have been deemed essential under state and local pandemic mitigation orders, and all of its business segments continue to operate. The Company’s customers have generally directed the Company to maintain normal work schedules, where safe and possible. The Company’s business model has, thus far, proven resilient, and management continues to make efforts to adapt to the changing operational and economic environment resulting from the COVID-19 pandemic. Management’s top priority has been to take appropriate actions to protect the health and safety of its employees, customers and business partners, including adjusting its standard operating procedures to respond to evolving health guidelines. The COVID-19 pandemic has had a negative impact on the Company’s operations and is expected to continue to affect our future business activities for an unknown period of time. These impacts include lost productivity from governmental permitting approval delays, reduced crew productivity due to social distancing, other mitigation measures or other factors, the health and availability of work crews or other key personnel, including subcontractors or supply chain disruptions, and/or delayed project start dates or project shutdowns or cancellations that may be mandated or requested by governmental authorities or others, all of which could result in lower revenue or higher operating costs and/or create lower levels of overhead cost absorption. The CARES Act was signed into law in March 2020 in response to the COVID-19 pandemic. The CARES Act provides for various tax relief and incentive measures, including provisions permitting the deferral and/or reduction of certain federal and payroll tax amounts. The Company has pursued certain of these relief provisions. For the year ended December 31, 2020, approximately $59 million of payroll taxes have been deferred, of which half are due by December 31, 2021, with the remainder due by December 31, 2022. Additionally, the Coronavirus Response and Relief Supplemental Appropriations Act (the “Coronavirus Relief Act”), which provides certain additional COVID-19 relief measures, was signed into law in December 2020. The Company will continue to evaluate the potential effects of the CARES Act, along with any potential effects of the Coronavirus Relief Act, on its financial position, results of operations and cash flows and will continue to monitor all other available federal and other COVID-19 relief provisions to determine its qualification for, and the usefulness to the Company, of any such relief measures. Management believes that it is taking appropriate steps to mitigate any potential impact to the Company; however, given the uncertainty regarding the potential effects of the COVID-19 pandemic, which will depend upon numerous evolving factors that we may not be able to accurately predict, including the development and availability of effective treatments and vaccines and the speed with which they are administered to the public and the length and extent of the economic and market disruption, any future impacts cannot be quantified or predicted with specificity.
Reclassifications	When necessary, certain prior year amounts have been reclassified to conform with the current period presentation.
Translation of Foreign Currencies	Translation of Foreign CurrenciesThe assets and liabilities of foreign subsidiaries with a functional currency other than the U.S. dollar are translated into U.S. dollars at period-end exchange rates, with resulting translation gains or losses included within other comprehensive income or loss. Revenue and expenses are translated into U.S. dollars at average rates of exchange during the applicable period. Substantially all of the Company’s foreign operations use their local currency as their functional currency. Currency gains or losses resulting from transactions executed in currencies other than the functional currency are included in other income or expense, net.
Management Estimates	Management Estimates The preparation of consolidated financial statements in accordance with U.S. GAAP requires the use of estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates are based on historical experience and various other assumptions that management believes to be reasonable under the circumstances, including the potential future effects of the COVID-19 pandemic and other relevant global events. These estimates form the basis for making judgments about the Company’s operating results and the carrying values of assets and liabilities that are not readily apparent from other sources. While management believes that such estimates are reasonable when considered in conjunction with the Company’s consolidated financial position and results of operations taken as a whole, actual results could differ materially from these estimates. Key estimates include: the recognition of revenue and project profit or loss, which the Company defines as project revenue, less project costs of revenue, including project-related depreciation, in particular, on construction contracts accounted for under the cost-to-cost method, for which the recorded amounts require estimates of costs to complete and the amount and probability of variable consideration included in the contract transaction price; fair value estimates, including those related to acquisitions, valuations of goodwill and intangible assets, acquisition-related contingent consideration and other liabilities, equity investments and other long-lived assets; allowances for credit losses; asset lives used in computing depreciation and amortization; fair values of financial instruments; self-insurance liabilities; other accruals and allowances; income taxes; and the estimated effects of litigation and other contingencies.
Revenue Recognition	Revenue Recognition The Company recognizes revenue from contracts with customers under Accounting Standards Codification (“ASC”) Topic 606 (“Topic 606”). Under Topic 606, revenue is recognized when, or as, control of promised goods and services is transferred to customers, and the amount of revenue recognized reflects the consideration to which an entity expects to be entitled in exchange for the goods and services transferred. Revenue is primarily recognized by the Company over time utilizing the cost-to-cost measure of progress, which is an input method, on contracts for specific projects and for certain master service and other service agreements. Under Topic 606, the cost-to-cost measure of progress best depicts the continuous transfer of control of goods or services to the customer, and correspondingly, when performance obligations are satisfied for the related contracts. Contracts. The Company derives revenue primarily from construction projects performed under: (i) master and other service agreements, which provide a menu of available services in a specific geographic territory that are utilized on an as-needed basis, and are typically priced using either a time and materials or a fixed price per unit basis; and (ii) contracts for specific projects requiring the construction and installation of an entire infrastructure system or specified units within an infrastructure system, which are subject to multiple pricing options, including fixed price, unit price, time and materials, or cost plus a markup. Revenue derived from projects performed under master service and other service agreements totaled 36% of consolidated revenue for each of the years ended December 31, 2020 and 2019, and totaled 35% for the year ended December 31, 2018. Revenue from contracts for specific projects, as well as for certain projects pursuant to master and other service agreements, is typically recognized over time using the cost-to-cost measure of progress. For these contracts, the cost-to-cost measure of progress best depicts the continuous transfer of control of goods or services to the customer. Such contracts provide that the customer accept completion of progress to date and compensate the Company for services rendered. For certain master service and other service agreements under which the Company performs installation and maintenance services, primarily for install-to-the-home service providers in its Communications segment, revenue is recognized at a point in time. This is generally when the work order has been fulfilled, which is typically the same day the work is initiated. Point in time revenue accounted for approximately 5% of consolidated revenue for each of the years ended December 31, 2020 and 2019, and accounted for approximately 7% of consolidated revenue for the year ended December 31, 2018. Substantially all of the Company’s other revenue is recognized over time. Contract costs include all direct materials, labor and subcontracted costs, as well as indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and the operational costs of capital equipment. The total contract transaction price and cost estimation processes used for recognizing revenue over time under the cost-to-cost method is based on the professional knowledge and experience of the Company’s project managers, engineers and financial professionals. Management reviews estimates of total contract transaction price and total project costs on an ongoing basis. Changes in job performance, job conditions and management’s assessment of expected variable consideration are factors that influence estimates of the total contract transaction price, total costs to complete those contracts and the Company’s profit recognition. Changes in these factors could result in revisions to revenue in the period in which the revisions are determined, which could materially affect the Company’s consolidated results of operations for that period. Provisions for losses on uncompleted contracts are recorded in the period in which such losses are determined. For each of the years ended December 31, 2020, 2019 and 2018, project profit was affected by less than 5% as a result of changes in contract estimates included in projects that were in process as of December 31, 2019, 2018 and 2017. Revenue recognized for the years ended December 31, 2020, 2019 and 2018 as a result of changes in total contract transaction price estimates, including from variable consideration, from performance obligations satisfied or partially satisfied in prior periods, totaled approximately $13.5 million, $58.3 million and $38.5 million, respectively. The Company may incur certain costs that can be capitalized, such as initial set-up or mobilization costs. Such costs, which are amortized over the life of the respective projects, were $5.5 million as of December 31, 2020 and were not material as of December 31, 2019. The timing of customer billings is generally dependent upon advance billing terms, milestone billings based on completion of certain phases of work, or when services are provided. Under the typical payment terms of master and other service agreements and fixed price contracts, the customer makes progress payments based on quantifiable measures of performance by the Company as defined by each specific agreement. Progress payments, generally net of amounts retained, are paid by the customer over the duration of the contract. For install-to-the-home contracts, work orders are billed and paid as completed. Amounts billed and due from customers, as well as the amount of contract assets, are generally classified within current assets in the consolidated balance sheets. See Note 5 - Accounts Receivable, Net of Allowance, and Contract Assets and Liabilities for related discussion. Amounts expected to be collected beyond one year are classified as other long-term assets. Performance Obligations. A performance obligation is a contractual promise to transfer a distinct good or service to a customer, and is the unit of account under Topic 606. The transaction price of a contract is allocated to each distinct performance obligation and recognized as revenue when or as the performance obligation is satisfied. The Company’s contracts often require significant services to integrate complex activities and equipment into a single deliverable, and are therefore generally accounted for as a single performance obligation, even when delivering multiple distinct services. Contract amendments and change orders, which are generally not distinct from the existing contract, are typically accounted for as a modification of the existing contract and performance obligation. The vast majority of the Company’s performance obligations are completed within one year. When more than one contract is entered into with a customer on or close to the same date, the Company evaluates whether those contracts should be combined and accounted for as a single contract, as well as whether those contracts should be accounted for as one, or more than one, performance obligation. This evaluation requires significant judgment and is based on the facts and circumstances of the various contracts. Remaining performance obligations represent the amount of unearned transaction prices under contracts for which work is wholly or partially unperformed, including the Company’s share of unearned transaction prices from its proportionately consolidated non-controlled joint ventures. As of December 31, 2020, the amount of the Company’s remaining performance obligations was $5.0 billion. The Company expects to recognize approximately $4.6 billion of its remaining performance obligations as revenue during 2021, with the remainder to be recognized primarily in 2022. Variable Consideration. Transaction prices for the Company’s contracts may include variable consideration, which comprises items such as change orders, claims and incentives. Management estimates variable consideration for a performance obligation utilizing estimation methods that it believes best predict the amount of consideration to which the Company will be entitled. Variable consideration is included in the estimated transaction price if it is probable that when the uncertainty associated with the variable consideration is resolved, there will not be a significant reversal of the cumulative amount of revenue that has been recognized. Management’s estimates of variable consideration and the determination of whether to include estimated amounts in transaction prices are based largely on engineering studies and legal opinions, past practices with the customer, specific discussions, correspondence or preliminary negotiations with the customer and all other relevant information that is reasonably available at the time of the estimate. The effect of variable consideration on the transaction price of a performance obligation is typically recognized as an adjustment to revenue on a cumulative catch-up basis, as such variable consideration, which typically pertains to changed conditions and scope, is generally for services encompassed under the existing contract. To the extent unapproved change orders, claims and other variable consideration reflected in transaction prices are not resolved in the Company’s favor, or to the extent incentives reflected in transaction prices are not earned, there could be reductions in, or reversals of, previously recognized revenue. As of December 31, 2020 and 2019, the Company included approximately $51 million and $27 million, respectively, of change orders and/or claims in transaction prices for certain contracts that were in the process of being resolved in the ordinary course of business, including through negotiation, arbitration and other proceedings. These transaction price adjustments, when earned, are included within contract assets or accounts receivable, net of allowance, as appropriate. As of December 31, 2020, these change orders and/or claims were primarily related to certain projects in the Company’s Electrical Transmission and Communications segments, and as of December 31, 2019, change orders were primarily related to certain projects in the Company’s Oil and Gas segment. The Company actively engages with its customers to complete the final approval process, and generally expects these processes to be completed within one year. Amounts ultimately realized upon final agreement by customers could be higher or lower than such estimated amounts.
Allowance for Credit Losses	Allowance for Credit Losses See “Recent Accounting Pronouncements” section below for information pertaining to the adoption of ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments and its related clarifying ASUs (collectively, “ASU 2016-13”). The Company maintains an allowance for credit losses for its financial instruments, which are primarily composed of accounts receivable and contract assets. The measurement and recognition of credit losses involves the use of judgment and represents management’s estimate of expected lifetime credit losses based on historical experience and trends, current conditions and reasonable and supportable forecasts. Management’s assessment of expected credit losses includes consideration of current and expected economic, market and industry factors affecting the Company’s customers, including their financial condition, the aging of account balances, historical credit loss experience, customer concentrations, customer credit-worthiness, availability of mechanics’ and other liens, existence of payment bonds and other sources of payment. Management evaluates its experience with historical losses and then applies this historical loss ratio to financial assets with similar characteristics. The Company’s historical loss ratio or its determination of risk pools may be adjusted for changes in customer, economic, market or other circumstances. The Company may also establish an allowance for credit losses for specific receivables when it is probable that the receivable will not be collected and the loss can be reasonably estimated. Amounts are written off against the allowance when they are considered to be uncollectible, and reversals of previously reserved amounts are recognized if a specifically reserved item is settled for an amount exceeding the previous estimate. Estimates of expected credit losses could be affected by many factors, including, but not limited to: changes in credit loss experience, changes to the risk characteristics of the Company’s financial asset portfolio, developing trends, including changes in credit quality or unanticipated financial difficulties affecting the Company’s customers and changes in management’s expectations of future economic, industry or other conditions. In addition, if anticipated recoveries in existing bankruptcies or other work-out situations fail to materialize, additional allowances may be required. Estimates of collectibility are subject to significant change during times of economic weakness or uncertainty in either the overall economy or within the industries served by MasTec. Management actively monitors these factors and assesses the sufficiency of its allowance for credit losses on an ongoing basis, including any potential effects from the COVID-19 pandemic and/or volatility in the oil and gas markets on the credit quality of the Company’s customers and/or its financial assets.
Inventories	InventoriesInventories consist of materials and supplies for construction and installation projects, which are valued at the lower of cost or net realizable value using the average cost or specific identification methods of costing. For materials or supplies purchased on behalf of specific customers or projects, loss of the customer or cancellation of the project could result in an impairment of the value of materials purchased. The value of inventory may also decrease due to obsolescence, physical deterioration, damage, changes in price levels, or other causes. Inventory valuation allowances are determined based upon specific facts and circumstances and market conditions.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash consisting of interest-bearing demand deposits is carried at cost, which approximates fair value. Highly liquid investments with an original maturity of three months or less are carried at fair value. On a daily basis, available funds are swept from the Company’s depository accounts into a concentration account and are used to repay outstanding revolving loans, if any, under the Company’s senior secured credit facility (the “Credit Facility”). Cash balances maintained by certain operating subsidiaries and by entities that are proportionately consolidated that are not swept into the concentration account, as well as deposits made subsequent to the daily cash sweep, are classified as cash. Included in the Company’s cash balances as of December 31, 2020 and 2019 are amounts held by entities that are proportionately consolidated totaling $8.2 million and $13.1 million, respectively. These amounts are available to support the operations of those entities, but are not available for the Company’s other operations. The Company generally does not fund its disbursement accounts for checks it has written until the checks are presented to the bank for payment. Outstanding checks that have not yet cleared through the banking system represent book overdrafts, which are classified within accounts payable. There are no compensating balance requirements associated with the Company’s depository accounts and there are no other restrictions on the transfer of cash associated with the Company’s depository accounts.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments include cash and cash equivalents, accounts and notes receivable, cash collateral deposited with insurance carriers, life insurance assets, equity investments, certain other investments, deferred compensation plan assets and liabilities, accounts payable and other current liabilities, acquisition-related contingent consideration, mandatorily redeemable non-controlling interests, convertible debentures and debt obligations. Fair value is the price that would be received to sell an asset or the amount paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value guidance establishes a valuation hierarchy, which requires maximizing the use of observable inputs when measuring fair value. The three levels of inputs that may be used are: (i) Level 1 - quoted market prices in active markets for identical assets or liabilities; (ii) Level 2 - observable market-based inputs or other observable inputs; and (iii) Level 3 - significant unobservable inputs that cannot be corroborated by observable market data, which are generally determined using valuation models incorporating management estimates of market participant assumptions. In instances in which the inputs used to measure fair value fall into different levels of the fair value hierarchy, the fair value measurement classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Management’s assessment of the significance of a particular item to the fair value measurement in its entirety requires judgment, including the consideration of inputs specific to the asset or liability. Fair values of financial instruments are estimated using public market prices, quotes from financial institutions and other available information. Due to their short-term maturity, the carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and other current liabilities approximate their fair values. Management believes the carrying values of notes and other receivables, cash collateral deposited with insurance carriers, and outstanding balances on its credit facilities approximate their fair values.
Variable Interest Entities	Management determines whether each business entity in which it has equity interests, debt, or other investments constitutes a variable interest entity (“VIE”) based on the nature and characteristics of such arrangements. If an investment arrangement is determined to be a VIE, then management determines if the Company is the VIE’s primary beneficiary by evaluating several factors, including the Company’s: (i) risks and responsibilities; (ii) ownership interests; (iii) decision making powers; and (iv) financial interests, among other factors. If management determines the Company is the primary beneficiary of a VIE, then it would be consolidated, and other parties’ interests in the VIE would be accounted for as non-controlling interests. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the primary activities of the VIE and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, which, in either case, could be significant to the VIE
Equity Method Investments	The Company’s investments in entities for which it does not have a controlling interest and is not the primary beneficiary, but for which it has the ability to exert significant influence, are accounted for using the equity method of accounting. Under the equity method of accounting, the initial investment is recorded at cost and the investment is subsequently adjusted for its proportionate share of earnings or losses, including consideration of basis differences resulting from the difference between the initial carrying amount of the investment and the underlying equity in net assets. Equity method investments are recorded as other long-term assets. Income or loss from these investments is recorded as a separate line item in the consolidated statements of operations. Intercompany profits or losses associated with the Company’s equity method investments are eliminated until realized by the investee in transactions with third parties. Distributions received from equity method investees are reflected in the statements of cash flows using the nature of distributions approach, under which distributions are classified based on the nature of the activity that generated them.
Unicorporated Entities, Proportional Consolidation	For equity investees in which the Company has an undivided interest in the assets, liabilities and profits or losses of an unincorporated entity, but the Company does not exercise control over the entity, the Company consolidates its proportional interest in the accounts of the entity.
Other Equity Investments With Readily Determinable Fair Values	Equity investments, other than those accounted for as equity method investments or those that are proportionately consolidated, are measured at fair value if their fair values are readily determinable.
Other Equity Investments Without Readily Determinable Fair Values	Equity investments that do not have readily determinable fair values are measured at cost, adjusted for changes from observable market transactions, if any, less impairment (“adjusted cost basis”).
Deferred Financing Costs	Deferred Financing CostsDeferred financing costs relate to the Company’s debt instruments, the short and long-term portions of which are reflected as deductions from the carrying amounts of the related debt instrument, including the Credit Facility. Deferred financing costs are amortized over the terms of the related debt instruments using the effective interest method.
Property and Equipment	Purchased property and equipment are recorded at cost, or, if acquired in a business combination, at the acquisition date fair value. Finance lease assets are recognized based on the present value of minimum future lease payments. Certain costs incurred in connection with developing or obtaining internal-use software are capitalized within office furniture and equipment. Depreciation and amortization of property and equipment, including finance lease assets, is computed using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are depreciated over the shorter of the term of the lease or the estimated useful lives of the improvements. Expenditures for repairs and maintenance are charged to expense as incurred. Expenditures for betterments and major improvements that extend the life of the related assets are capitalized and depreciated over the remaining useful lives of the assets. The carrying amounts of assets sold or retired and the related accumulated depreciation are eliminated in the year of disposal, with resulting gains or losses included in other income or expense.
Finite-Lived Intangible Assets	Finite-lived intangible assets are amortized over their useful lives, which are generally based on contractual or legal rights, in a manner consistent with the pattern in which the related benefits are expected to be consumed.
Impairment of Long-Lived Assets	Management reviews long-lived assets for impairment whenever events or changes in circumstances indicate that their carrying amounts may not be recoverable. If an evaluation is required, the estimated future undiscounted cash flows associated with the asset are compared with the asset’s carrying amount to determine if there has been an impairment, which is calculated as the difference between the fair value of an asset and its carrying value. Estimates of future undiscounted cash flows are based on expected revenue and operating costs for the business as well as anticipated future economic conditions. Fair values take into consideration management’s estimates of risk-adjusted discount rates, which are believed to be consistent with assumptions that marketplace participants would use in their estimates of fair value.
Goodwill and Indefinite-Lived Intangible Assets	Goodwill and indefinite-lived intangible assets are not amortized, but instead are tested for impairment at least annually. The Company performs its annual impairment tests of goodwill and indefinite-lived intangible assets during the fourth quarter of each year, and on a quarterly basis, monitors these assets for potential indicators of impairment. Goodwill is required to be tested for impairment at the reporting unit level. A reporting unit is an operating segment, or one level below the operating segment, which is referred to as a component. Management identifies its reporting units by assessing whether components (i) have discrete financial information available; (ii) engage in business activities; and (iii) have a segment manager that regularly reviews the component’s operating results. If two or more components are deemed economically similar, those components are aggregated into one reporting unit when performing the annual goodwill impairment test.
Business Combinations	Business Combinations The determination of the fair value of net assets acquired in a business combination requires estimates and judgments of future cash flow expectations for the acquired business and the related identifiable tangible and intangible assets. Fair values of net assets acquired are calculated using expected cash flows and industry-standard valuation techniques. For current assets and current liabilities, book value is generally assumed to equal fair value. Goodwill is the amount by which consideration paid exceeds the fair value of acquired net assets. Acquisition costs, including acquisition integration costs, are expensed as incurred and are included within general and administrative expenses in the consolidated statements of operations. Due to the time required to gather and analyze the necessary data for each acquisition, U.S. GAAP provides a “measurement period” of up to one year in which to finalize these fair value determinations. During the measurement period, preliminary fair value estimates may be revised if new information is obtained about the facts and circumstances existing as of the date of acquisition, or based on the final net assets and working capital of the acquired business, as prescribed in the applicable purchase agreement. Such adjustments may result in the recognition, or adjust the fair values, of acquisition-related assets and liabilities and/or consideration paid, and are referred to as “measurement period” adjustments, and are recorded to goodwill. Other revisions to these fair value estimates are reflected as income or expense, as appropriate. Consideration paid generally consists of cash and potential future payments that are contingent upon the acquired business achieving certain levels of earnings in the future, also referred to as “acquisition-related contingent consideration” or “earn-outs.” In one of the Company’s acquisitions, the acquisition consideration includes a mandatorily redeemable non-controlling interest, subject to a repurchase formula, which is calculated in a manner consistent with the Company’s traditional earn-out arrangements. The Company refers to its traditional earn-out arrangements and the mandatorily redeemable non-controlling interest collectively as “Earn-outs.” Earn-out liabilities are measured at their estimated fair values as of the date of acquisition. Subsequent to the date of acquisition, if future Earn-out payments are expected to differ from Earn-out payments estimated as of the date of acquisition, any related fair value adjustments, including those related to finalization of completed earn-out arrangements, are recognized in the period that such expectation is considered probable. Changes in the fair value of Earn-out liabilities for the Company’s traditional earn-outs, other than those related to measurement period adjustments, as described above, are recorded within other income or expense in the consolidated statements of operations, and for mandatorily redeemable non-controlling interests, are generally recorded within interest expense. Fair values are estimated using income approaches such as discounted cash flows or option pricing models. Earn-out liabilities are included within other current and other long-term liabilities, as appropriate, within the consolidated balance sheets. Earn-out payments, to the extent they relate to estimated liabilities as of the date of acquisition, are classified within financing activities in the consolidated statement of cash flows. Earn-out payments in excess of acquisition date liabilities are classified within operating activities.
Leases	Leases In the ordinary course of business, the Company enters into agreements that provide financing for machinery and equipment and for other of its facility, vehicle and equipment needs, including related party leases. The Company reviews all agreements to determine if a leasing arrangement exists. When a leasing arrangement is identified, a determination is made at inception as to whether the lease is an operating or a finance lease. A lease exists when a contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. In determining whether a lease exists, the Company considers whether a contract provides both the right to obtain substantially all of the economic benefits from the use of an asset and the right to direct the use of the asset. Right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of the minimum future lease payments over the expected term of the lease. The Company’s lease assets are primarily concentrated in vehicles, machinery and equipment. Leases with an initial term of twelve months or less are classified as short-term leases and are not recognized in the consolidated balance sheets unless the lease contains a purchase option that is reasonably certain to be exercised, or unless it is reasonably certain that the equipment will be leased for greater than twelve months. Lease payments for short-term leases are recognized on a straight-line basis over the lease term, and primarily relate to equipment used on construction projects, for which the rentals are based on daily, weekly or monthly rental rates, and typically contain termination for convenience provisions. Lease determinations are reassessed in the event of a change in lease terms. The Company has a limited number of sublease arrangements, which are not considered material to the consolidated financial statements. As of December 31, 2020, the Company’s leases have remaining lease terms of up to eight years. Lease agreements may contain renewal clauses, which, if elected, generally extend the term of the lease for one to five years for both equipment and facility leases. Certain lease agreements may also contain options to purchase the leased property and/or options to terminate the lease. In addition, lease agreements may include periodic adjustments to payment amounts for inflation or other variables, or may require payments for taxes, insurance, maintenance or other expenses, which are generally referred to as non-lease components. The Company accounts for non-lease components together with the related lease components for all classes of leased assets. The Company’s lease agreements do not contain significant residual value guarantees or material restrictive covenants. Lease term, discount rate, variable lease costs and future minimum lease payment determinations require the use of judgment, and are based on the facts and circumstances of each lease. Economic incentives, intent, past history and business need are among the factors considered to determine if renewal and/or purchase options are reasonably certain to be exercised. The majority of the Company’s lease agreements do not explicitly state the discount rate implicit in the lease, therefore, the Company generally uses an incremental borrowing rate to determine the value of its lease obligations. The incremental borrowing rate represents the rate of interest that would be paid to borrow on a collateralized basis over a similar term. The Company determines its incremental borrowing rate using a portfolio approach based on information available as of the lease commencement date, including applicable lease terms and the current economic environment. Finance Leases Finance lease assets are recorded within property and equipment, with a corresponding amount recorded within the Company’s debt obligations. Finance lease expense is composed of depreciation expense on the leased asset and interest on the lease liability. Additions to finance leases are included within the supplemental disclosures of non-cash information in the consolidated statements of cash flows. Many of the Company’s finance leases contain purchase options, which the Company frequently exercises, given that the purchase option prices are typically below the estimated fair market values of the related assets. Operating Leases Operating lease right-of-use assets and liabilities are recorded on the consolidated balance sheets, with the related lease expense recognized over the term of the lease on a straight-line basis. Operating lease expense is recorded as rent expense, primarily within costs of revenue, excluding depreciation and amortization. Fixed costs for operating leases are composed of initial base rent amounts plus any fixed annual increases. Variable costs for operating leases consist primarily of common area maintenance expenses and taxes for facility leases. Certain of the Company’s operating leases contain purchase options, for which the purchase option price is generally considered to be at fair market value. From time to time, the Company may terminate a lease before the end of the lease term. Payments related to such early lease terminations are generally recorded within rent expense.
Self-Insurance	Self-Insurance The Company is self-insured up to the amount of its deductible for its insurance policies. MasTec maintains insurance policies subject to per claim deductibles of $2.0 million for its workers’ compensation policy, $4.0 million for its general liability policy and up to $10.0 million for its automobile liability policy. In addition, the Company has excess umbrella coverage. Estimated liabilities under these insurance programs are accrued based upon management’s estimates of the ultimate liability for claims reported and an estimate of claims incurred but not reported, with assistance from third-party actuaries. MasTec also maintains an insurance policy with respect to employee group medical claims, which is subject to annual per employee maximum losses of $0.6 million. MasTec’s estimated liability for employee group medical claims is based on statistical analysis of historical claims experience and specific knowledge of actual losses that have occurred. The Company is required to post collateral, generally in the form of letters of credit, surety bonds and cash to certain of its insurance carriers. Cash collateral deposited with insurance carriers is included in other long-term assets in the consolidated balance sheets. The present value of the Company’s self-insurance liability is reflected in the consolidated balance sheets within current and other long-term liabilities, as appropriate. The determination of such claims and expenses and the appropriateness of the related liability is reviewed and updated quarterly. These insurance liabilities are, however, difficult to assess and estimate due to many factors, the effects of which are often unknown or difficult to estimate, including the severity of an injury, the determination of the Company’s liability in proportion to other parties and the number of incidents not reported. Accruals are based upon known facts and historical trends. Although management believes its accruals are adequate, a change in experience or actuarial assumptions could materially affect the Company’s results of operations in a particular period.
Income Taxes	Income Taxes The Company records income taxes using the asset and liability method of accounting for deferred income taxes. Under this method, deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial statement and income tax basis of the Company’s assets and liabilities. Income taxes are estimated in each of the jurisdictions in which the Company operates. This process involves estimating the tax exposure, together with assessing temporary differences resulting from differing treatment of items, such as deferred revenue, for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included, net, within the consolidated balance sheets as long-term assets and/or liabilities, as appropriate. The recording of a deferred tax asset assumes the realization of such asset in the future. Otherwise, a valuation allowance is recorded to reduce the asset to its estimated net realizable value. If management determines that the Company may not be able to realize all or part of a deferred tax asset in the future, a valuation allowance for the deferred tax asset is charged to income tax expense in the period the determination is made. Management considers future pretax income and ongoing prudent and feasible tax planning strategies in assessing the estimated net realizable value of tax assets and the corresponding need for any related valuation allowances. In determining the provision for income taxes, management uses an effective tax rate based on annual pre-tax income, statutory tax rates, permanent tax differences and tax planning opportunities in the various jurisdictions in which the Company operates. The Company is generally free of additional U.S. federal tax consequences on distributed foreign subsidiary earnings. The Company has generally not provided for U.S. income taxes on unremitted foreign earnings because such earnings are considered to be insignificant. Significant factors that can affect the annual effective tax rate include management’s assessment of certain tax matters, the location and amount of taxable earnings, changes in certain non-deductible expenses and expected credits. An entity may only recognize or continue to recognize tax positions that meet a "more likely than not" threshold. In the ordinary course of business, there is inherent uncertainty in quantifying income tax positions. The Company assesses its income tax positions and records tax benefits for all years subject to examination based on management's evaluation of the facts, circumstances and information available at the reporting date. For those tax positions where it is more likely than not that a tax benefit will be sustained, the Company has recognized the largest amount of tax benefit with a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where it is not more likely than not that a tax benefit will be sustained, no tax benefit has been recognized in the Company's financial statements. The Company and its subsidiaries file income tax returns in numerous tax jurisdictions, including U.S. federal, most U.S. states and certain foreign jurisdictions. Although management believes its calculations for tax returns are correct and the positions taken thereon are reasonable, the final outcome of income tax examinations could be materially different from the resolution management currently anticipates and the estimates that are reflected in the Company’s consolidated financial statements, which could materially affect the Company’s results of operations, cash flows and liquidity in a particular period. To the extent interest and penalties are assessed by taxing authorities, such amounts are accrued and included within income tax expense.
Income Tax Uncertainties	An entity may only recognize or continue to recognize tax positions that meet a "more likely than not" threshold. In the ordinary course of business, there is inherent uncertainty in quantifying income tax positions. The Company assesses its income tax positions and records tax benefits for all years subject to examination based on management's evaluation of the facts, circumstances and information available at the reporting date. For those tax positions where it is more likely than not that a tax benefit will be sustained, the Company has recognized the largest amount of tax benefit with a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where it is not more likely than not that a tax benefit will be sustained, no tax benefit has been recognized in the Company's financial statements.
Stock-Based Compensation	Stock-Based Compensation The Company has certain stock-based compensation plans, under which restricted stock awards and restricted stock units (together “restricted shares”) are available for issuance to eligible participants. Non-cash stock-based compensation expense is included within general and administrative expense in the consolidated statements of operations. Share-based payments, to the extent they are compensatory, are recognized based on their grant date fair values. Forfeitures are recorded as they occur. The Company records a deferred tax asset, or future tax benefit, based on the amount of share-based compensation recognized in the financial statements over the vesting period of share-based awards. The tax effects of differences between the fair value of a share-based award on the date of vesting and the date of grant, also referred to as excess tax benefits or tax deficiencies, are recognized within the provision for income taxes in the period such vestings occur. Grants of restricted shares are valued based on the closing market share price of MasTec’s common stock as reported on the New York Stock Exchange (the “market price”) on the date of grant. Compensation expense arising from restricted shares is recognized on a straight-line basis over the vesting period. Grants of restricted shares have cliff vesting terms, which generally vest over a period of three years. Upon vesting, some of the underlying shares may be sold to cover the required tax withholdings. However, some participants may choose the net share settlement method to cover withholding tax requirements, in which case shares are not issued, but are treated as common stock repurchases in the consolidated financial statements, as they reduce the number of shares that would have been issued upon vesting. The Company then pays the corresponding withholding taxes to the appropriate taxing authorities in cash on behalf of the recipient. Withheld shares, which are valued at the market price on the date of vesting, are recorded as a reduction to additional paid-in capital and are reflected within financing activities in the consolidated statements of cash flows. For the year ended December 31, 2020, shares withheld in connection with stock-based compensation arrangements totaled 11,667 shares and related payments to taxing authorities totaled $0.6 million. For the year ended December 31, 2019, shares withheld in connection with stock-based compensation arrangements were de minimis. Shares withheld in connection with stock-based compensation arrangements for the year ended December 31, 2018 totaled 96,739 shares and related payments to taxing authorities totaled $3.8 million. The Company has certain employee stock purchase plans (collectively, “ESPPs”) under which shares of the Company’s common stock are available for purchase by eligible participants. These plans allow participants to purchase MasTec, Inc. common stock at 85% of its fair market value at the lower of (i) the date of commencement of the offering period or (ii) the last day of the exercise period, as defined in the plan documents. The fair value of purchases under the Company’s employee stock purchase plans is estimated using the Black-Scholes option-pricing valuation model. The determination of fair value of stock-based awards using an option-pricing model is affected by the Company’s stock price as well as assumptions pertaining to several variables, including expected stock price volatility, the expected term of the award and the risk-free rate of interest. In the option-pricing model for the Company’s employee stock purchase plans, expected stock price volatility is based on historical volatility of the Company’s common stock. The expected term of the award is based on historical and expected exercise patterns and the risk-free rate of interest is based on U.S. Treasury yields. Beginning in 2021, ESPP shares will be purchased at 85% of the fair market value of MasTec common stock as of the date of purchase.
Collective Bargaining Agreements and Multiemployer Plans	Collective Bargaining Agreements and Multiemployer Plans Certain of MasTec’s subsidiaries, including certain subsidiaries in Canada, are party to various collective bargaining agreements with unions representing certain of their employees. These agreements require the subsidiaries party to the agreements to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to multiemployer pension and other multiemployer benefit plans and trusts (“MEPPs”). These contributions are recorded as a component of employee wages and salaries within costs of revenue, excluding depreciation and amortization. Contributions are generally based on fixed amounts per hour per employee for employees covered under these plans. Multiemployer plan contribution rates are determined annually and assessed on a “pay-as-you-go” basis based on union employee payrolls. The Pension Protection Act of 2006, as amended, (the “PPA”) requires pension plans that are underfunded to improve their funding ratios within prescribed intervals based on their level of underfunding, under which benefit reductions may apply and/or participating employers could be required to make additional contributions. In addition, if a multiemployer defined benefit plan fails to satisfy certain minimum funding requirements, the IRS may impose on the employers contributing to such plans a non-deductible excise tax of 5% of the amount of the accumulated funding deficiency. Union payrolls cannot be determined for future periods because the number of union employees employed at any given time, and the plans in which they may participate, vary depending upon the location and number of ongoing projects at a given time and the need for union resources in connection with those projects. The collective bargaining agreements expire at various times and have typically been renegotiated and renewed on terms similar to the ones contained in the expiring agreements. Under current law pertaining to employers that are contributors to U.S.-registered multiemployer defined benefit plans, a plan’s termination, an employer’s voluntary withdrawal from, or the mass withdrawal of contributing employers from, an underfunded multiemployer defined benefit plan requires participating employers to make payments to the plan for their proportionate share of the multiemployer plan’s unfunded vested liabilities. These liabilities include an allocable share of the unfunded vested benefits of the plan for all plan participants, not only for benefits payable to participants of the contributing employer. As a result, participating employers may bear a higher proportion of liability for unfunded vested benefits if the other participating employers cease to contribute to, or withdraw from, the plan. The allocable portion of liability to participating employers could be more disproportionate if employers that have withdrawn from the plan are insolvent, or if they otherwise fail to pay their proportionate share of the withdrawal liability. If the Company is subject to a withdrawal liability, the related withdrawal charge is recorded as a component of employee wages and salaries within costs of revenue, excluding depreciation and amortization, with any related liability recorded within other current and/or other long-term liabilities, as appropriate. The Company’s participation in the multiemployer pension plans is evaluated by management on an ongoing basis.
Restructuring Activities	Restructuring Activities From time to time, the Company may incur costs to streamline its business operations. These streamlining efforts, which are designed to improve profitability, could include eliminating service offerings that no longer fit into the Company’s business plan, certain integration activities for acquired businesses, reducing or eliminating services or operations that do not produce adequate revenue or margins, or reducing costs of business units that need margin improvements. The costs associated with these efforts, which the Company refers to as restructuring charges, include such items as employee separation costs, lease termination expenses and losses on disposal of excess fixed assets. When these efforts are related to circumstances that are significant, unique in nature and outside of the course of the Company’s normal and periodic business streamlining efforts, the related amount of restructuring charges included within the consolidated financial statements is aggregated and accompanied by a discussion of the nature of such restructuring activities. Restructuring charges are included within the applicable line item(s) in the consolidated statement of operations based on the nature of the expense incurred.
Litigation and Contingencies	Litigation and Contingencies Accruals for litigation and contingencies are reflected in the consolidated financial statements based on management’s assessment, including advice of legal counsel, of the expected outcome of litigation or other dispute resolution proceedings and/or the expected resolution of contingencies. Liabilities for estimated losses are accrued if the potential loss from any claim or legal proceeding is considered probable and the amount can be reasonably estimated. Significant judgment is required in both the determination of probability of loss and the determination as to whether the amount is reasonably estimable. Accruals are based on information available at the time of the assessment due to the uncertain nature of such matters. As additional information becomes available, management reassesses potential liabilities related to pending claims and litigation and may revise its previous estimates, which could materially affect the Company’s results of operations in a given period.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income or loss is a measure of net income and other changes in equity that result from transactions other than those with shareholders. Comprehensive income or loss and related accumulated comprehensive income or loss balances consist of net income, foreign currency translation adjustments, primarily from fluctuations in foreign currency exchange rates of the Company’s foreign subsidiaries with a functional currency other than the U.S. dollar, unrealized gains and losses from certain investment activities and net income or loss attributable to non-controlling interests.
Recent Accounting Pronouncements	Recent Accounting Pronouncements See allowance for credit losses discussion within Significant Accounting Policies above, and the recent accounting pronouncements discussion below, for information pertaining to the effects of recently adopted and other recent accounting pronouncements. Accounting Pronouncements Adopted in 2020 In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40) Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”) to reduce diversity in practice in accounting for the costs of implementing cloud computing arrangements that are service contracts. ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a cloud computing arrangement that is a service contract with the requirements for internal-use software. Accounting for the service element of the cloud computing arrangement is not affected by the new guidance. Under ASU 2018-15, amortization expense, payments for and asset balances related to such capitalized implementation costs are to be presented within the same line items of the entity’s statements of operations, cash flows and balance sheets, respectively, as the related service fee activity and balances would be presented. ASU 2018-15, which the Company adopted on a prospective basis during the first quarter of 2020, did not have a material effect on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). ASU 2018-13, which is intended to improve the effectiveness of fair value measurement disclosures, modifies the disclosure requirements for certain estimates and assumptions used in determining the fair value of assets and liabilities. ASU 2018-13, which the Company adopted during the first quarter of 2020, did not have a material effect on the Company’s consolidated financial statements. See Note 4 - Fair Value of Financial Instruments for disclosure updates pertaining to significant unobservable inputs used to develop fair value estimates for certain of the Company’s Level 3 financial instruments. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments. This ASU, together with its related clarifying ASUs (collectively, “ASU 2016-13”), introduced an expected credit loss methodology for the measurement and recognition of credit losses on most financial assets, including financial assets arising from revenue transactions, such as accounts receivable and contract assets. The new expected credit loss methodology, which is based on historical experience, current conditions and reasonable and supportable forecasts, replaced the incurred loss model for measuring and recognizing expected credit losses. The Company adopted this ASU in the first quarter of 2020 and incorporated this guidance into its methodology for estimating its accounts receivable allowances. Based on historical trends, the financial condition of the Company’s customers and management’s expectations of economic and industry factors affecting the Company’s customers, ASU 2016-13 did not have a material effect on the Company’s consolidated financial statements upon adoption. For additional information about the Company’s allowance for credit losses see discussion within Significant Accounting Policies above, and Note 5 - Accounts Receivable, Net of Allowance, and Contract Assets and Liabilities. Accounting Pronouncements To Be Adopted in 2021 In January 2020, the FASB issued ASU 2020-01, Investments-Equity Securities (Topic 321), Investments-Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815): Clarifying the Interactions between Topic 321, Topic 323, and Topic 815 (“ASU 2020-01”) to clarify the interaction in accounting for equity securities under Topic 321, investments accounted for under the equity method of accounting in Topic 323 and the accounting for certain forward contracts and purchased options accounted for under Topic 815. ASU 2020-01 is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2020. This ASU is not expected to have a material effect on the Company’s consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which eliminates certain exceptions to the existing guidance for income taxes related to the approach for intra-period tax allocations, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. This ASU also simplifies the accounting for income taxes by clarifying and amending existing guidance related to the effects of enacted changes in tax laws or rates in the effective tax rate computation, the recognition of franchise tax and the evaluation of a step-up in the tax basis of goodwill, among other clarifications. ASU 2019-12 is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2020. The Company is currently evaluating the potential effects of this ASU, however, does not expect that its adoption will have a material effect on the Company’s consolidated financial statements. Other Recent Accounting Pronouncements In March 2020, the FASB issued ASU 2020-04, Reference Reform Rate (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”) to provide temporary optional expedients and exceptions to the contract modifications, hedge relationships and other transactions affected by reference rate reform if certain criteria are met. This ASU, which was effective upon issuance and may be applied through December 31, 2022, is applicable to all contracts and hedging relationships that reference the London Interbank Offered Rate or any other reference rate expected to be discontinued. The guidance in ASU 2020-04 may be implemented over time as reference rate reform activities occur. The Company is currently evaluating the potential effects of this ASU, however, does not expect reference rate reform to have a material effect on its consolidated financial statements as the Company’s current Credit Facility agreement provides for the replacement of LIBOR with an alternative benchmark rate should LIBOR become unavailable.

Business, Basis of Presentation and Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Principles of ConsolidationThe accompanying consolidated financial statements include MasTec, Inc. and its subsidiaries and include the accounts of all majority owned subsidiaries over which the Company exercises control and, when applicable, entities in which the Company has a controlling financial interest. All significant intercompany balances and transactions have been eliminated in consolidation. Other parties’ interests in entities that MasTec consolidates are reported as non-controlling interests within equity, except for mandatorily redeemable non-controlling interests, which are recorded within liabilities. Net income or loss attributable to non-controlling interests is reported as a separate line item below net income or loss. The Company’s investments in entities for which the Company does not have a controlling interest, but over which it has the ability to exert significant influence, are accounted for using the equity method of accounting. For equity investees in which the Company has an undivided interest in the assets, liabilities and profits or losses of an unincorporated entity, but does not exercise control over the entity, the Company consolidates its proportional interest in the accounts of the entity.

COVID-19 Disclosure

COVID-19 Pandemic

The World Health Organization declared a global pandemic related to the rapidly growing outbreak of a novel strain of coronavirus in the first quarter of 2020. The COVID-19 pandemic has disrupted business activities and significantly affected global economic conditions as federal, state and local governments imposed mitigation measures to address the public health crisis, resulting in workforce, supply chain and production disruptions, the effects of which have created significant uncertainties in the U.S. and global economies. Restrictions have been enacted, lifted, and reenacted during 2020 and into 2021, and the possibility of future restrictions remains.

Most of the Company’s construction services have been deemed essential under state and local pandemic mitigation orders, and all of its business segments continue to operate. The Company’s customers have generally directed the Company to maintain normal work schedules, where safe and possible. The Company’s business model has, thus far, proven resilient, and management continues to make efforts to adapt to the changing operational and economic environment resulting from the COVID-19 pandemic. Management’s top priority has been to take appropriate actions to protect the health and safety of its employees, customers and business partners, including adjusting its standard operating procedures to respond to

evolving health guidelines. The COVID-19 pandemic has had a negative impact on the Company’s operations and is expected to continue to affect our future business activities for an unknown period of time. These impacts include lost productivity from governmental permitting approval delays, reduced crew productivity due to social distancing, other mitigation measures or other factors, the health and availability of work crews or other key personnel, including subcontractors or supply chain disruptions, and/or delayed project start dates or project shutdowns or cancellations that may be mandated or requested by governmental authorities or others, all of which could result in lower revenue or higher operating costs and/or create lower levels of overhead cost absorption.

The CARES Act was signed into law in March 2020 in response to the COVID-19 pandemic. The CARES Act provides for various tax relief and incentive measures, including provisions permitting the deferral and/or reduction of certain federal and payroll tax amounts. The Company has pursued certain of these relief provisions. For the year ended December 31, 2020, approximately $59 million of payroll taxes have been deferred, of which half are due by December 31, 2021, with the remainder due by December 31, 2022. Additionally, the Coronavirus Response and Relief Supplemental Appropriations Act (the “Coronavirus Relief Act”), which provides certain additional COVID-19 relief measures, was signed into law in December 2020. The Company will continue to evaluate the potential effects of the CARES Act, along with any potential effects of the Coronavirus Relief Act, on its financial position, results of operations and cash flows and will continue to monitor all other available federal and other COVID-19 relief provisions to determine its qualification for, and the usefulness to the Company, of any such relief measures.

Management believes that it is taking appropriate steps to mitigate any potential impact to the Company; however, given the uncertainty regarding the potential effects of the COVID-19 pandemic, which will depend upon numerous evolving factors that we may not be able to accurately predict, including the development and availability of effective treatments and vaccines and the speed with which they are administered to the public and the length and extent of the economic and market disruption, any future impacts cannot be quantified or predicted with specificity.

Reclassifications

When necessary, certain prior year amounts have been reclassified to conform with the current period presentation.

Translation of Foreign Currencies

Translation of Foreign CurrenciesThe assets and liabilities of foreign subsidiaries with a functional currency other than the U.S. dollar are translated into U.S. dollars at period-end exchange rates, with resulting translation gains or losses included within other comprehensive income or loss. Revenue and expenses are translated into U.S. dollars at average rates of exchange during the applicable period. Substantially all of the Company’s foreign operations use their local currency as their functional currency. Currency gains or losses resulting from transactions executed in currencies other than the functional currency are included in other income or expense, net.

Management Estimates

The preparation of consolidated financial statements in accordance with U.S. GAAP requires the use of estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates are based on historical experience and various other assumptions that management believes to be reasonable under the circumstances, including the potential future effects of the COVID-19 pandemic and other relevant global events. These estimates form the basis for making judgments about the Company’s operating results and the carrying values of assets and liabilities that are not readily apparent from other sources. While management believes that such estimates are reasonable when considered in conjunction with the Company’s consolidated financial position and results of operations taken as a whole, actual results could differ materially from these estimates.

Key estimates include: the recognition of revenue and project profit or loss, which the Company defines as project revenue, less project costs of revenue, including project-related depreciation, in particular, on construction contracts accounted for under the cost-to-cost method, for which the recorded amounts require estimates of costs to complete and the amount and probability of variable consideration included in the contract transaction price; fair value estimates, including those related to acquisitions, valuations of goodwill and intangible assets, acquisition-related contingent consideration and other liabilities, equity investments and other long-lived assets; allowances for credit losses; asset lives used in computing depreciation and amortization; fair values of financial instruments; self-insurance liabilities; other accruals and allowances; income taxes; and the estimated effects of litigation and other contingencies.

Revenue Recognition

The Company recognizes revenue from contracts with customers under Accounting Standards Codification (“ASC”) Topic 606 (“Topic 606”). Under Topic 606, revenue is recognized when, or as, control of promised goods and services is transferred to customers, and the amount of revenue recognized reflects the consideration to which an entity expects to be entitled in exchange for the goods and services transferred. Revenue is primarily recognized by the Company over time utilizing the cost-to-cost measure of progress, which is an input method, on contracts for specific projects and for certain master service and other service agreements. Under Topic 606, the cost-to-cost measure of progress best depicts the continuous transfer of control of goods or services to the customer, and correspondingly, when performance obligations are satisfied for the related contracts.

Contracts. The Company derives revenue primarily from construction projects performed under: (i) master and other service agreements, which provide a menu of available services in a specific geographic territory that are utilized on an as-needed basis, and are typically priced using either a time and materials or a fixed price per unit basis; and (ii) contracts for specific projects requiring the construction and installation of an entire infrastructure system or specified units within an infrastructure system, which are subject to multiple pricing options, including fixed price, unit price, time and materials, or cost plus a markup. Revenue derived from projects performed under master service and other service agreements totaled 36% of consolidated revenue for each of the years ended December 31, 2020 and 2019, and totaled 35% for the year ended December 31, 2018.

Revenue from contracts for specific projects, as well as for certain projects pursuant to master and other service agreements, is typically recognized over time using the cost-to-cost measure of progress. For these contracts, the cost-to-cost measure of progress best depicts the continuous transfer of control of goods or services to the customer. Such contracts provide that the customer accept completion of progress to date and compensate the Company for services rendered.

For certain master service and other service agreements under which the Company performs installation and maintenance services, primarily for install-to-the-home service providers in its Communications segment, revenue is recognized at a point in time. This is generally when the work order has been fulfilled, which is typically the same day the work is initiated. Point in time revenue accounted for approximately 5% of consolidated revenue for each of the years ended December 31, 2020 and 2019, and accounted for approximately 7% of consolidated revenue for the year ended December 31, 2018. Substantially all of the Company’s other revenue is recognized over time.

Contract costs include all direct materials, labor and subcontracted costs, as well as indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and the operational costs of capital equipment. The total contract transaction price and cost estimation processes used for recognizing revenue over time under the cost-to-cost method is based on the professional knowledge and experience of the Company’s project managers, engineers and financial professionals. Management reviews estimates of total contract transaction price and total project costs on an ongoing basis. Changes in job performance, job conditions and management’s assessment of expected variable consideration are factors that influence estimates of the total contract transaction price, total costs to complete those contracts and the Company’s profit recognition. Changes in these factors could result in revisions to revenue in the period in which the revisions are determined, which could materially affect the Company’s consolidated results of operations for that period. Provisions for losses on uncompleted contracts are recorded in the period in which such losses are determined. For each of the years ended December 31, 2020, 2019 and 2018, project profit was affected by less than 5% as a result of changes in contract estimates included in projects that were in process as of December 31, 2019, 2018 and 2017. Revenue recognized for the years ended December 31, 2020, 2019 and 2018 as a result of changes in total contract transaction price estimates, including from variable consideration, from performance obligations satisfied or partially satisfied in prior periods, totaled approximately $13.5 million, $58.3 million and $38.5 million, respectively.

The Company may incur certain costs that can be capitalized, such as initial set-up or mobilization costs. Such costs, which are amortized over the life of the respective projects, were $5.5 million as of December 31, 2020 and were not material as of December 31, 2019.

The timing of customer billings is generally dependent upon advance billing terms, milestone billings based on completion of certain phases of work, or when services are provided. Under the typical payment terms of master and other service agreements and fixed price contracts, the customer makes progress payments based on quantifiable measures of performance by the Company as defined by each specific agreement. Progress payments, generally net of amounts retained, are paid by the customer over the duration of the contract. For install-to-the-home contracts, work orders are billed and paid as completed. Amounts billed and due from customers, as well as the amount of contract assets, are generally classified within current assets in the consolidated balance sheets. See Note 5 - Accounts Receivable, Net of Allowance, and Contract Assets and Liabilities for related discussion. Amounts expected to be collected beyond one year are classified as other long-term assets.

Performance Obligations. A performance obligation is a contractual promise to transfer a distinct good or service to a customer, and is the unit of account under Topic 606. The transaction price of a contract is allocated to each distinct performance obligation and recognized as revenue when or as the performance obligation is satisfied. The Company’s contracts often require significant services to integrate complex activities and equipment into a single deliverable, and are therefore generally accounted for as a single performance obligation, even when delivering multiple distinct services. Contract amendments and change orders, which are generally not distinct from the existing contract, are typically accounted for as a modification of the existing contract and performance obligation. The vast majority of the Company’s performance obligations are completed within one year.

When more than one contract is entered into with a customer on or close to the same date, the Company evaluates whether those contracts should be combined and accounted for as a single contract, as well as whether those contracts should be accounted for as one, or more than one, performance obligation. This evaluation requires significant judgment and is based on the facts and circumstances of the various contracts.

Remaining performance obligations represent the amount of unearned transaction prices under contracts for which work is wholly or partially unperformed, including the Company’s share of unearned transaction prices from its proportionately consolidated non-controlled joint ventures. As of December 31, 2020, the amount of the Company’s remaining performance obligations was $5.0 billion. The Company expects to recognize approximately $4.6 billion of its remaining performance obligations as revenue during 2021, with the remainder to be recognized primarily in 2022.

Variable Consideration. Transaction prices for the Company’s contracts may include variable consideration, which comprises items such as change orders, claims and incentives. Management estimates variable consideration for a performance obligation utilizing estimation methods that it believes best predict the amount of consideration to which the Company will be entitled. Variable consideration is included in the estimated transaction price if it is probable that when the uncertainty associated with the variable consideration is resolved, there will not be a significant reversal of the cumulative amount of revenue that has been recognized. Management’s estimates of variable consideration and the determination of whether to include estimated amounts in transaction prices are based largely on engineering studies and legal opinions, past practices with the customer, specific discussions, correspondence or preliminary negotiations with the customer and all other relevant information that is reasonably available at the time of the estimate. The effect of variable consideration on the transaction price of a performance obligation is typically recognized as an adjustment to revenue on a cumulative catch-up basis, as such variable consideration, which typically pertains to changed conditions and scope, is generally for services encompassed under the existing contract. To the extent unapproved change orders, claims and other variable consideration reflected in transaction prices are not resolved in the Company’s favor, or to the extent incentives reflected in transaction prices are not earned, there could be reductions in, or reversals of, previously recognized revenue.

As of December 31, 2020 and 2019, the Company included approximately $51 million and $27 million, respectively, of change orders and/or claims in transaction prices for certain contracts that were in the process of being resolved in the ordinary course of business, including through negotiation, arbitration and other proceedings. These transaction price adjustments, when earned, are included within contract assets or accounts receivable, net of allowance, as appropriate. As of December 31, 2020, these change orders and/or claims were primarily related to certain projects in the Company’s Electrical Transmission and Communications segments, and as of December 31, 2019, change orders were primarily related to certain projects in the Company’s Oil and Gas segment. The Company actively engages with its customers to complete the final approval process, and generally expects these processes to be completed within one year. Amounts ultimately realized upon final agreement by customers could be higher or lower than such estimated amounts.

Allowance for Credit Losses

See “Recent Accounting Pronouncements” section below for information pertaining to the adoption of ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments and its related clarifying ASUs (collectively, “ASU 2016-13”). The Company maintains an allowance for credit losses for its financial instruments, which are primarily composed of accounts receivable and contract assets. The measurement and recognition of credit losses involves the use of judgment and represents management’s estimate of expected lifetime credit losses based on historical experience and trends, current conditions and reasonable and supportable forecasts. Management’s assessment of expected credit losses includes consideration of current and expected economic, market and industry factors affecting the Company’s customers, including their financial condition, the aging of account balances, historical credit loss experience, customer concentrations, customer credit-worthiness, availability of mechanics’ and other liens, existence of payment bonds and other sources of payment. Management evaluates its experience with historical losses and then applies this historical loss ratio to financial assets with similar characteristics. The Company’s historical loss ratio or its determination of risk pools may be adjusted for changes in customer, economic, market or other circumstances. The Company may also establish an allowance for credit losses for specific receivables when it is probable that the receivable will not be collected and the loss can be reasonably estimated. Amounts are written off against the allowance when they are considered to be uncollectible, and reversals of previously reserved amounts are recognized if a specifically reserved item is settled for an amount exceeding the previous estimate.

Estimates of expected credit losses could be affected by many factors, including, but not limited to: changes in credit loss experience, changes to the risk characteristics of the Company’s financial asset portfolio, developing trends, including changes in credit quality or unanticipated financial difficulties affecting the Company’s customers and changes in management’s expectations of future economic, industry or other conditions. In addition, if anticipated recoveries in existing bankruptcies or other work-out situations fail to materialize, additional allowances may be required. Estimates of collectibility are subject to significant change during times of economic weakness or uncertainty in either the overall economy or within the industries served by MasTec. Management actively monitors these factors and assesses the sufficiency of its allowance for credit losses on an

ongoing basis, including any potential effects from the COVID-19 pandemic and/or volatility in the oil and gas markets on the credit quality of the Company’s customers and/or its financial assets.

Inventories

InventoriesInventories consist of materials and supplies for construction and installation projects, which are valued at the lower of cost or net realizable value using the average cost or specific identification methods of costing. For materials or supplies purchased on behalf of specific customers or projects, loss of the customer or cancellation of the project could result in an impairment of the value of materials purchased. The value of inventory may also decrease due to obsolescence, physical deterioration, damage, changes in price levels, or other causes. Inventory valuation allowances are determined based upon specific facts and circumstances and market conditions.

Cash and Cash Equivalents

Cash consisting of interest-bearing demand deposits is carried at cost, which approximates fair value. Highly liquid investments with an original maturity of three months or less are carried at fair value. On a daily basis, available funds are swept from the Company’s depository accounts into a concentration account and are used to repay outstanding revolving loans, if any, under the Company’s senior secured credit facility (the “Credit Facility”). Cash balances maintained by certain operating subsidiaries and by entities that are proportionately consolidated that are not swept into the concentration account, as well as deposits made subsequent to the daily cash sweep, are classified as cash. Included in the Company’s cash balances as of December 31, 2020 and 2019 are amounts held by entities that are proportionately consolidated totaling $8.2 million and $13.1 million, respectively. These amounts are available to support the operations of those entities, but are not available for the Company’s other operations. The Company generally does not fund its disbursement accounts for checks it has written until the checks are presented to the bank for payment. Outstanding checks that have not yet cleared through the banking system represent book overdrafts, which are classified within accounts payable. There are no compensating balance requirements associated with the Company’s depository accounts and there are no other restrictions on the transfer of cash associated with the Company’s depository accounts.

Fair Value of Financial Instruments

The Company’s financial instruments include cash and cash equivalents, accounts and notes receivable, cash collateral deposited with insurance carriers, life insurance assets, equity investments, certain other investments, deferred compensation plan assets and liabilities, accounts payable and other current liabilities, acquisition-related contingent consideration, mandatorily redeemable non-controlling interests, convertible debentures and debt obligations.

Fair value is the price that would be received to sell an asset or the amount paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value guidance establishes a valuation hierarchy, which requires maximizing the use of observable inputs when measuring fair value. The three levels of inputs that may be used are: (i) Level 1 - quoted market prices in active markets for identical assets or liabilities; (ii) Level 2 - observable market-based inputs or other observable inputs; and (iii) Level 3 - significant unobservable inputs that cannot be corroborated by observable market data, which are generally determined using valuation models incorporating management estimates of market participant assumptions. In instances in which the inputs used to measure fair value fall into different levels of the fair value hierarchy, the fair value measurement classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Management’s assessment of the significance of a particular item to the fair value measurement in its entirety requires judgment, including the consideration of inputs specific to the asset or liability.

Fair values of financial instruments are estimated using public market prices, quotes from financial institutions and other available information. Due to their short-term maturity, the carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and other current liabilities approximate their fair values. Management believes the carrying values of notes and other receivables, cash collateral deposited with insurance carriers, and outstanding balances on its credit facilities approximate their fair values.

Variable Interest Entities

Management determines whether each business entity in which it has equity interests, debt, or other investments constitutes a variable interest entity (“VIE”) based on the nature and characteristics of such arrangements. If an investment arrangement is determined to be a VIE, then management determines if the Company is the VIE’s primary beneficiary by evaluating several factors, including the Company’s: (i) risks and responsibilities; (ii) ownership interests; (iii) decision making powers; and (iv) financial interests, among other factors. If management determines the Company is the primary beneficiary of a VIE, then it would be consolidated, and other parties’ interests in the VIE would be accounted for as non-controlling interests. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the primary activities of the VIE and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, which, in either case, could be significant to the VIE

Equity Method Investments

The Company’s investments in entities for which it does not have a controlling interest and is not the primary beneficiary, but for which it has the ability to exert significant influence, are accounted for using the equity method of accounting. Under the equity method of accounting, the initial investment is recorded at cost and the investment is subsequently adjusted for its proportionate share of earnings or losses, including consideration of basis differences resulting from the difference between the initial carrying amount of the investment and the underlying equity in net assets. Equity method investments are recorded as other long-term assets. Income or loss from these investments is recorded as a separate line item in the consolidated statements of operations. Intercompany profits or losses associated with the Company’s equity method investments are eliminated until realized by the investee in transactions with third parties. Distributions received from equity method investees are reflected in the statements of cash flows using the nature of distributions approach, under which distributions are classified based on the nature of the activity that generated them.

Unicorporated Entities, Proportional Consolidation

For equity investees in which the Company has an undivided interest in the assets, liabilities and profits or losses of an unincorporated entity, but the Company does not exercise control over the entity, the Company consolidates its proportional interest in the accounts of the entity.

Other Equity Investments With Readily Determinable Fair Values

Equity investments, other than those accounted for as equity method investments or those that are proportionately consolidated, are measured at fair value if their fair values are readily determinable.

Other Equity Investments Without Readily Determinable Fair Values

Equity investments that do not have readily determinable fair values are measured at cost, adjusted for changes from observable market transactions, if any, less impairment (“adjusted cost basis”).

Deferred Financing Costs

Deferred Financing CostsDeferred financing costs relate to the Company’s debt instruments, the short and long-term portions of which are reflected as deductions from the carrying amounts of the related debt instrument, including the Credit Facility. Deferred financing costs are amortized over the terms of the related debt instruments using the effective interest method.

Property and Equipment

Purchased property and equipment are recorded at cost, or, if acquired in a business combination, at the acquisition date fair value. Finance lease assets are recognized based on the present value of minimum future lease payments. Certain costs incurred in connection with developing or obtaining internal-use software are capitalized within office furniture and equipment. Depreciation and amortization of property and equipment, including finance lease assets, is computed using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are depreciated over the shorter of the term of the lease or the estimated useful lives of the improvements. Expenditures for repairs and maintenance are charged to expense as incurred. Expenditures for betterments and major improvements that extend the life of the related assets are capitalized and depreciated over the remaining useful lives of the assets. The carrying amounts of assets sold or retired and the related accumulated depreciation are eliminated in the year of disposal, with resulting gains or losses included in other income or expense.

Finite-Lived Intangible Assets

Finite-lived intangible assets are amortized over their useful lives, which are generally based on contractual or legal rights, in a manner consistent with the pattern in which the related benefits are expected to be consumed.

Impairment of Long-Lived Assets

Management reviews long-lived assets for impairment whenever events or changes in circumstances indicate that their carrying amounts may not be recoverable. If an evaluation is required, the estimated future undiscounted cash flows associated with the asset are compared with the asset’s carrying amount to determine if there has been an impairment, which is calculated as the difference between the fair value of an asset and its carrying value. Estimates of future undiscounted cash flows are based on expected revenue and operating costs for the business as well as anticipated future economic conditions. Fair values take into consideration management’s estimates of risk-adjusted discount rates, which are believed to be consistent with assumptions that marketplace participants would use in their estimates of fair value.

Goodwill and Indefinite-Lived Intangible Assets

Goodwill and indefinite-lived intangible assets are not amortized, but instead are tested for impairment at least annually. The Company performs its annual impairment tests of goodwill and indefinite-lived intangible assets during the fourth quarter of each year, and on a quarterly basis, monitors these assets for potential indicators of impairment. Goodwill is required to be tested for impairment at the reporting unit level. A reporting unit is an operating segment, or one level below the operating segment, which is referred to as a component. Management identifies its reporting units by assessing whether components (i) have discrete financial information available; (ii) engage in business activities; and (iii) have a segment manager that regularly reviews the component’s operating results. If two or more components are deemed economically similar, those components are aggregated into one reporting unit when performing the annual goodwill impairment test.

Business Combinations

The determination of the fair value of net assets acquired in a business combination requires estimates and judgments of future cash flow expectations for the acquired business and the related identifiable tangible and intangible assets. Fair values of net assets acquired are calculated

using expected cash flows and industry-standard valuation techniques. For current assets and current liabilities, book value is generally assumed to equal fair value. Goodwill is the amount by which consideration paid exceeds the fair value of acquired net assets. Acquisition costs, including acquisition integration costs, are expensed as incurred and are included within general and administrative expenses in the consolidated statements of operations.

Due to the time required to gather and analyze the necessary data for each acquisition, U.S. GAAP provides a “measurement period” of up to one year in which to finalize these fair value determinations. During the measurement period, preliminary fair value estimates may be revised if new information is obtained about the facts and circumstances existing as of the date of acquisition, or based on the final net assets and working capital of the acquired business, as prescribed in the applicable purchase agreement. Such adjustments may result in the recognition, or adjust the fair values, of acquisition-related assets and liabilities and/or consideration paid, and are referred to as “measurement period” adjustments, and are recorded to goodwill. Other revisions to these fair value estimates are reflected as income or expense, as appropriate.

Consideration paid generally consists of cash and potential future payments that are contingent upon the acquired business achieving certain levels of earnings in the future, also referred to as “acquisition-related contingent consideration” or “earn-outs.” In one of the Company’s acquisitions, the acquisition consideration includes a mandatorily redeemable non-controlling interest, subject to a repurchase formula, which is calculated in a manner consistent with the Company’s traditional earn-out arrangements. The Company refers to its traditional earn-out arrangements and the mandatorily redeemable non-controlling interest collectively as “Earn-outs.” Earn-out liabilities are measured at their estimated fair values as of the date of acquisition. Subsequent to the date of acquisition, if future Earn-out payments are expected to differ from Earn-out payments estimated as of the date of acquisition, any related fair value adjustments, including those related to finalization of completed earn-out arrangements, are recognized in the period that such expectation is considered probable. Changes in the fair value of Earn-out liabilities for the Company’s traditional earn-outs, other than those related to measurement period adjustments, as described above, are recorded within other income or expense in the consolidated statements of operations, and for mandatorily redeemable non-controlling interests, are generally recorded within interest expense. Fair values are estimated using income approaches such as discounted cash flows or option pricing models. Earn-out liabilities are included within other current and other long-term liabilities, as appropriate, within the consolidated balance sheets. Earn-out payments, to the extent they relate to estimated liabilities as of the date of acquisition, are classified within financing activities in the consolidated statement of cash flows. Earn-out payments in excess of acquisition date liabilities are classified within operating activities.

Leases

In the ordinary course of business, the Company enters into agreements that provide financing for machinery and equipment and for other of its facility, vehicle and equipment needs, including related party leases. The Company reviews all agreements to determine if a leasing arrangement exists. When a leasing arrangement is identified, a determination is made at inception as to whether the lease is an operating or a finance lease. A lease exists when a contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. In determining whether a lease exists, the Company considers whether a contract provides both the right to obtain substantially all of the economic benefits from the use of an asset and the right to direct the use of the asset. Right-of-use assets and lease liabilities are recognized at the lease commencement date based on the present value of the minimum future lease payments over the expected term of the lease. The Company’s lease assets are primarily concentrated in vehicles, machinery and equipment.

Leases with an initial term of twelve months or less are classified as short-term leases and are not recognized in the consolidated balance sheets unless the lease contains a purchase option that is reasonably certain to be exercised, or unless it is reasonably certain that the equipment will be leased for greater than twelve months. Lease payments for short-term leases are recognized on a straight-line basis over the lease term, and primarily relate to equipment used on construction projects, for which the rentals are based on daily, weekly or monthly rental rates, and typically contain termination for convenience provisions. Lease determinations are reassessed in the event of a change in lease terms. The Company has a limited number of sublease arrangements, which are not considered material to the consolidated financial statements.

As of December 31, 2020, the Company’s leases have remaining lease terms of up to eight years. Lease agreements may contain renewal clauses, which, if elected, generally extend the term of the lease for one to five years for both equipment and facility leases. Certain lease agreements may also contain options to purchase the leased property and/or options to terminate the lease. In addition, lease agreements may include periodic adjustments to payment amounts for inflation or other variables, or may require payments for taxes, insurance, maintenance or other expenses, which are generally referred to as non-lease components. The Company accounts for non-lease components together with the related lease components for all classes of leased assets. The Company’s lease agreements do not contain significant residual value guarantees or material restrictive covenants.

Lease term, discount rate, variable lease costs and future minimum lease payment determinations require the use of judgment, and are based on the facts and circumstances of each lease. Economic incentives, intent, past history and business need are among the factors considered to determine if renewal and/or purchase options are reasonably certain to be exercised. The majority of the Company’s lease agreements do not explicitly state the discount rate implicit in the lease, therefore, the Company generally uses an incremental borrowing rate to determine the value of its lease obligations. The incremental borrowing rate represents the rate of interest that would be paid to borrow on a collateralized basis over a similar term. The Company determines its incremental borrowing rate using a portfolio approach based on information available as of the lease commencement date, including applicable lease terms and the current economic environment.

Finance Leases

Finance lease assets are recorded within property and equipment, with a corresponding amount recorded within the Company’s debt obligations. Finance lease expense is composed of depreciation expense on the leased asset and interest on the lease liability. Additions to finance leases are included within the supplemental disclosures of non-cash information in the consolidated statements of cash flows. Many of the Company’s finance leases contain purchase options, which the Company frequently exercises, given that the purchase option prices are typically below the estimated fair market values of the related assets.

Operating Leases

Operating lease right-of-use assets and liabilities are recorded on the consolidated balance sheets, with the related lease expense recognized over the term of the lease on a straight-line basis. Operating lease expense is recorded as rent expense, primarily within costs of revenue, excluding depreciation and amortization. Fixed costs for operating leases are composed of initial base rent amounts plus any fixed annual increases. Variable costs for operating leases consist primarily of common area maintenance expenses and taxes for facility leases. Certain of the Company’s operating leases contain purchase options, for which the purchase option price is generally considered to be at fair market value. From time to time, the Company may terminate a lease before the end of the lease term. Payments related to such early lease terminations are generally recorded within rent expense.

Self-Insurance

The Company is self-insured up to the amount of its deductible for its insurance policies. MasTec maintains insurance policies subject to per claim deductibles of $2.0 million for its workers’ compensation policy, $4.0 million for its general liability policy and up to $10.0 million for its automobile liability policy. In addition, the Company has excess umbrella coverage. Estimated liabilities under these insurance programs are accrued based upon management’s estimates of the ultimate liability for claims reported and an estimate of claims incurred but not reported, with assistance from third-party actuaries. MasTec also maintains an insurance policy with respect to employee group medical claims, which is subject to annual per employee maximum losses of $0.6 million. MasTec’s estimated liability for employee group medical claims is based on statistical analysis of historical claims experience and specific knowledge of actual losses that have occurred. The Company is required to post collateral, generally in the form of letters of credit, surety bonds and cash to certain of its insurance carriers. Cash collateral deposited with insurance carriers is included in other long-term assets in the consolidated balance sheets.

The present value of the Company’s self-insurance liability is reflected in the consolidated balance sheets within current and other long-term liabilities, as appropriate. The determination of such claims and expenses and the appropriateness of the related liability is reviewed and updated quarterly. These insurance liabilities are, however, difficult to assess and estimate due to many factors, the effects of which are often unknown or difficult to estimate, including the severity of an injury, the determination of the Company’s liability in proportion to other parties and the number of incidents not reported. Accruals are based upon known facts and historical trends. Although management believes its accruals are adequate, a change in experience or actuarial assumptions could materially affect the Company’s results of operations in a particular period.

Income Taxes

The Company records income taxes using the asset and liability method of accounting for deferred income taxes. Under this method, deferred tax assets and liabilities are recognized for the expected future tax consequences of temporary differences between the financial statement and income tax basis of the Company’s assets and liabilities. Income taxes are estimated in each of the jurisdictions in which the Company operates. This process involves estimating the tax exposure, together with assessing temporary differences resulting from differing treatment of items, such as deferred revenue, for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included, net, within the consolidated balance sheets as long-term assets and/or liabilities, as appropriate. The recording of a deferred tax asset assumes the realization of such asset in the future. Otherwise, a valuation allowance is recorded to reduce the asset to its estimated net realizable value. If management determines that the Company may not be able to realize all or part of a deferred tax asset in the future, a valuation allowance for the deferred tax asset is charged to income tax expense in the period the determination is made. Management considers future pretax income and ongoing prudent and feasible tax planning strategies in assessing the estimated net realizable value of tax assets and the corresponding need for any related valuation allowances.

In determining the provision for income taxes, management uses an effective tax rate based on annual pre-tax income, statutory tax rates, permanent tax differences and tax planning opportunities in the various jurisdictions in which the Company operates. The Company is generally free of additional U.S. federal tax consequences on distributed foreign subsidiary earnings. The Company has generally not provided for U.S. income taxes on unremitted foreign earnings because such earnings are considered to be insignificant.

Significant factors that can affect the annual effective tax rate include management’s assessment of certain tax matters, the location and amount of taxable earnings, changes in certain non-deductible expenses and expected credits.

An entity may only recognize or continue to recognize tax positions that meet a "more likely than not" threshold. In the ordinary course of business, there is inherent uncertainty in quantifying income tax positions. The Company assesses its income tax positions and records tax benefits for all years subject to examination based on management's evaluation of the facts, circumstances and information available at the reporting date. For those tax positions where it is more likely than not that a tax benefit will be sustained, the Company has recognized the largest amount of tax benefit with a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where it is not more likely than not that a tax benefit will be sustained, no tax benefit has been recognized in the Company's financial statements.

The Company and its subsidiaries file income tax returns in numerous tax jurisdictions, including U.S. federal, most U.S. states and certain foreign jurisdictions. Although management believes its calculations for tax returns are correct and the positions taken thereon are reasonable, the final outcome of income tax examinations could be materially different from the resolution management currently anticipates and the estimates that are reflected in the Company’s consolidated financial statements, which could materially affect the Company’s results of operations, cash flows and liquidity in a particular period. To the extent interest and penalties are assessed by taxing authorities, such amounts are accrued and included within income tax expense.

Income Tax Uncertainties

Stock-Based Compensation

The Company has certain stock-based compensation plans, under which restricted stock awards and restricted stock units (together “restricted shares”) are available for issuance to eligible participants. Non-cash stock-based compensation expense is included within general and administrative expense in the consolidated statements of operations. Share-based payments, to the extent they are compensatory, are recognized

based on their grant date fair values. Forfeitures are recorded as they occur. The Company records a deferred tax asset, or future tax benefit, based on the amount of share-based compensation recognized in the financial statements over the vesting period of share-based awards. The tax effects of differences between the fair value of a share-based award on the date of vesting and the date of grant, also referred to as excess tax benefits or tax deficiencies, are recognized within the provision for income taxes in the period such vestings occur.

Grants of restricted shares are valued based on the closing market share price of MasTec’s common stock as reported on the New York Stock Exchange (the “market price”) on the date of grant. Compensation expense arising from restricted shares is recognized on a straight-line basis over the vesting period. Grants of restricted shares have cliff vesting terms, which generally vest over a period of three years. Upon vesting, some of the underlying shares may be sold to cover the required tax withholdings. However, some participants may choose the net share settlement method to cover withholding tax requirements, in which case shares are not issued, but are treated as common stock repurchases in the consolidated financial statements, as they reduce the number of shares that would have been issued upon vesting. The Company then pays the corresponding withholding taxes to the appropriate taxing authorities in cash on behalf of the recipient. Withheld shares, which are valued at the market price on the date of vesting, are recorded as a reduction to additional paid-in capital and are reflected within financing activities in the consolidated statements of cash flows. For the year ended December 31, 2020, shares withheld in connection with stock-based compensation arrangements totaled 11,667 shares and related payments to taxing authorities totaled $0.6 million. For the year ended December 31, 2019, shares withheld in connection with stock-based compensation arrangements were de minimis. Shares withheld in connection with stock-based compensation arrangements for the year ended December 31, 2018 totaled 96,739 shares and related payments to taxing authorities totaled $3.8 million.

The Company has certain employee stock purchase plans (collectively, “ESPPs”) under which shares of the Company’s common stock are available for purchase by eligible participants. These plans allow participants to purchase MasTec, Inc. common stock at 85% of its fair market value at the lower of (i) the date of commencement of the offering period or (ii) the last day of the exercise period, as defined in the plan documents. The fair value of purchases under the Company’s employee stock purchase plans is estimated using the Black-Scholes option-pricing valuation model. The determination of fair value of stock-based awards using an option-pricing model is affected by the Company’s stock price as well as assumptions pertaining to several variables, including expected stock price volatility, the expected term of the award and the risk-free rate of interest. In the option-pricing model for the Company’s employee stock purchase plans, expected stock price volatility is based on historical volatility of the Company’s common stock. The expected term of the award is based on historical and expected exercise patterns and the risk-free rate of interest is based on U.S. Treasury yields. Beginning in 2021, ESPP shares will be purchased at 85% of the fair market value of MasTec common stock as of the date of purchase.

Collective Bargaining Agreements and Multiemployer Plans

Certain of MasTec’s subsidiaries, including certain subsidiaries in Canada, are party to various collective bargaining agreements with unions representing certain of their employees. These agreements require the subsidiaries party to the agreements to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to multiemployer pension and other multiemployer benefit plans and trusts (“MEPPs”). These contributions are recorded as a component of employee wages and salaries within costs of revenue, excluding depreciation and amortization. Contributions are generally based on fixed amounts per hour per employee for employees covered under these plans. Multiemployer plan contribution rates are determined annually and assessed on a “pay-as-you-go” basis based on union employee payrolls. The Pension Protection Act of 2006, as amended, (the “PPA”) requires pension plans that are underfunded to improve their funding ratios within prescribed intervals based on their level of underfunding, under which benefit reductions may apply and/or participating employers could be required to make additional contributions. In addition, if a multiemployer defined benefit plan fails to satisfy certain minimum funding requirements, the IRS may impose on the employers contributing to such plans a non-deductible excise tax of 5% of the amount of the accumulated funding deficiency. Union payrolls cannot be determined for future periods because the number of union employees employed at any given time, and the plans in which they may participate, vary depending upon the location and number of ongoing projects at a given time and the need for union resources in connection with those projects. The collective bargaining agreements expire at various times and have typically been renegotiated and renewed on terms similar to the ones contained in the expiring agreements.

Under current law pertaining to employers that are contributors to U.S.-registered multiemployer defined benefit plans, a plan’s termination, an employer’s voluntary withdrawal from, or the mass withdrawal of contributing employers from, an underfunded multiemployer defined benefit plan requires participating employers to make payments to the plan for their proportionate share of the multiemployer plan’s unfunded vested liabilities. These liabilities include an allocable share of the unfunded vested benefits of the plan for all plan participants, not only for benefits payable to participants of the contributing employer. As a result, participating employers may bear a higher proportion of liability for unfunded vested benefits if the other participating employers cease to contribute to, or withdraw from, the plan. The allocable portion of liability to participating employers could be more disproportionate if employers that have withdrawn from the plan are insolvent, or if they otherwise fail to pay their proportionate share of the withdrawal liability. If the Company is subject to a withdrawal liability, the related withdrawal charge is recorded as a component of employee wages and salaries within costs of revenue, excluding depreciation and amortization, with any related liability recorded within other current and/or other long-term liabilities, as appropriate. The Company’s participation in the multiemployer pension plans is evaluated by management on an ongoing basis.

Restructuring Activities

From time to time, the Company may incur costs to streamline its business operations. These streamlining efforts, which are designed to improve profitability, could include eliminating service offerings that no longer fit into the Company’s business plan, certain integration activities for acquired businesses, reducing or eliminating services or operations that do not produce adequate revenue or margins, or reducing costs of business units that need margin improvements. The costs associated with these efforts, which the Company refers to as restructuring charges, include such items as employee separation costs, lease termination expenses and losses on disposal of excess fixed assets. When these efforts are related to circumstances that are significant, unique in nature and outside of the course of the Company’s normal and periodic business streamlining efforts, the related amount of restructuring charges included within the consolidated financial statements is aggregated and accompanied by a discussion of the nature of such restructuring activities. Restructuring charges are included within the applicable line item(s) in the consolidated statement of operations based on the nature of the expense incurred.

Litigation and Contingencies

Accruals for litigation and contingencies are reflected in the consolidated financial statements based on management’s assessment, including advice of legal counsel, of the expected outcome of litigation or other dispute resolution proceedings and/or the expected resolution of contingencies. Liabilities for estimated losses are accrued if the potential loss from any claim or legal proceeding is considered probable and the amount can be reasonably estimated. Significant judgment is required in both the determination of probability of loss and the determination as to whether the amount is reasonably estimable. Accruals are based on information available at the time of the assessment due to the uncertain nature of such matters. As additional information becomes available, management reassesses potential liabilities related to pending claims and litigation and may revise its previous estimates, which could materially affect the Company’s results of operations in a given period.

Comprehensive Income (Loss)

Comprehensive income or loss is a measure of net income and other changes in equity that result from transactions other than those with shareholders. Comprehensive income or loss and related accumulated comprehensive income or loss balances consist of net income, foreign currency translation adjustments, primarily from fluctuations in foreign currency exchange rates of the Company’s foreign subsidiaries with a functional currency other than the U.S. dollar, unrealized gains and losses from certain investment activities and net income or loss attributable to non-controlling interests.

Recent Accounting Pronouncements

See allowance for credit losses discussion within Significant Accounting Policies above, and the recent accounting pronouncements discussion below, for information pertaining to the effects of recently adopted and other recent accounting pronouncements.

Accounting Pronouncements Adopted in 2020

In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40) Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (“ASU 2018-15”) to reduce diversity in practice in accounting for the costs of implementing cloud computing arrangements that are service contracts. ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a cloud computing arrangement that is a service contract with the requirements for internal-use software. Accounting for the service element of the cloud computing arrangement is not affected by the new guidance. Under ASU 2018-15, amortization expense, payments for and asset balances related to such capitalized implementation costs are to be presented within the same line items of the entity’s statements of operations, cash flows and balance sheets, respectively, as the related service fee activity and balances would be presented. ASU 2018-15, which the Company adopted on a prospective basis during the first quarter of 2020, did not have a material effect on the Company’s consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement (“ASU 2018-13”). ASU 2018-13, which is intended to improve the effectiveness of fair value measurement disclosures, modifies the disclosure requirements for certain estimates and assumptions used in determining the fair value of assets and liabilities. ASU 2018-13, which the Company adopted during the first quarter of 2020, did not have a material effect on the Company’s consolidated financial statements. See Note 4 - Fair Value of Financial Instruments for disclosure updates pertaining to significant unobservable inputs used to develop fair value estimates for certain of the Company’s Level 3 financial instruments.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments. This ASU, together with its related clarifying ASUs (collectively, “ASU 2016-13”), introduced an expected credit loss methodology for the measurement and recognition of credit losses on most financial assets, including financial assets arising from revenue transactions, such as accounts receivable and contract assets. The new expected credit loss methodology, which is based on historical experience, current conditions and reasonable and supportable forecasts, replaced the incurred loss model for measuring and recognizing expected credit losses. The Company adopted this ASU in the first quarter of 2020 and incorporated this guidance into its methodology for estimating its accounts receivable allowances. Based on historical trends, the financial condition of the Company’s customers and management’s expectations of economic and industry factors affecting the Company’s customers, ASU 2016-13 did not have a material effect on the Company’s consolidated financial statements upon adoption. For additional information about the Company’s allowance for credit losses see discussion within Significant Accounting Policies above, and Note 5 - Accounts Receivable, Net of Allowance, and Contract Assets and Liabilities.

Accounting Pronouncements To Be Adopted in 2021

In January 2020, the FASB issued ASU 2020-01, Investments-Equity Securities (Topic 321), Investments-Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815): Clarifying the Interactions between Topic 321, Topic 323, and Topic 815 (“ASU 2020-01”) to clarify the interaction in accounting for equity securities under Topic 321, investments accounted for under the equity method of accounting in Topic 323 and the accounting for certain forward contracts and purchased options accounted for under Topic 815. ASU 2020-01 is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2020. This ASU is not expected to have a material effect on the Company’s consolidated financial statements.

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which eliminates certain exceptions to the existing guidance for income taxes related to the approach for intra-period tax allocations, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. This ASU also simplifies the accounting for income taxes by clarifying and amending existing guidance related to the effects of enacted changes in tax laws or rates in the effective tax rate computation, the recognition of franchise tax and the evaluation of a step-up in the tax basis of goodwill, among other clarifications. ASU 2019-12 is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2020. The Company is currently evaluating the potential effects of this ASU, however, does not expect that its adoption will have a material effect on the Company’s consolidated financial statements.

Other Recent Accounting Pronouncements

In March 2020, the FASB issued ASU 2020-04, Reference Reform Rate (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”) to provide temporary optional expedients and exceptions to the contract modifications, hedge relationships and other transactions affected by reference rate reform if certain criteria are met. This ASU, which was effective upon issuance and may be applied through December 31, 2022, is applicable to all contracts and hedging relationships that reference the London Interbank Offered Rate or any other reference rate expected to be discontinued. The guidance in ASU 2020-04 may be implemented over time as reference rate reform activities occur. The Company is currently evaluating the potential effects of this ASU, however, does not expect reference rate reform to have a material effect on its consolidated financial statements as the Company’s current Credit Facility agreement provides for the replacement of LIBOR with an alternative benchmark rate should LIBOR become unavailable.