Fair Value of Financial Instruments	3 Months Ended
Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments are primarily composed of cash and cash equivalents, accounts receivable and contract assets, notes receivable, cash collateral deposited with insurance carriers, life insurance assets, equity investments, certain other assets and investments, deferred compensation plan assets and liabilities, accounts payable and other current liabilities, acquisition-related contingent consideration and other liabilities, and debt obligations. Fair value is the price that would be received to sell an asset or the amount paid to transfer a liability, also referred to as the “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, including quoted market prices for identical or similar assets or liabilities in markets that are not active; 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. Acquisition-Related Contingent Consideration Acquisition-related contingent consideration is composed of earn-outs, which represent the estimated fair value of future amounts payable for businesses, which we refer to as “Earn-outs,” that are contingent upon the acquired businesses achieving certain levels of earnings in the future. As of March 31, 2024 and December 31, 2023, the estimated fair value of the Company’s Earn-out liabilities totaled $71.3 million and $77.4 million, respectively. Earn-out liabilities included within other current liabilities totaled approximately $24.4 million and $29.8 million as of March 31, 2024 and December 31, 2023, respectively. The fair values of the Company’s Earn-out liabilities are estimated using income approaches such as discounted cash flows or option pricing models, both of which incorporate significant inputs not observable in the market (Level 3 inputs), including management’s estimates and entity-specific assumptions, and are evaluated on an ongoing basis. Key assumptions include the discount rate, which was 14.0% as of March 31, 2024, and probability-weighted projections of EBITDA. Significant changes in any of these assumptions could result in significantly higher or lower potential Earn-out liabilities. The ultimate payment amounts for the Company’s Earn-out liabilities will be determined based on the actual results achieved by the acquired businesses. As of March 31, 2024, the range of potential undiscounted Earn-out liabilities was estimated to be between $23 million and $86 million; however, there is no maximum payment amount. Earn-out activity consists primarily of additions from new business combinations; changes in the expected fair value of future payment obligations; and payments. For both the three month periods ended March 31, 2024 and 2023, there were no additions from new business combinations or measurement period adjustments. For the three month period ended March 31, 2024, fair value adjustments totaled a decrease, net, of approximately $6.1 million primarily related to acquisitions within the Company’s Communications segment. For the three month period ended March 31, 2023, fair value adjustments totaled a decrease, net, of approximately $0.3 million, including decreases related to acquisitions within the Company’s Communications and Clean Energy and Infrastructure segments, which were largely offset by an increase related to acquisitions within the Company’s Oil and Gas segment. There were no Earn-out payments for the three month period ended March 31, 2024, and for the three month period ended March 31, 2023, Earn-out payments totaled approximately $1.7 million and related to a mandatorily redeemable non-controlling interest arrangement that was completed in 2023. Investment and Strategic Arrangements From time to time, the Company may participate in selected investment or strategic arrangements, including equity interests in various business entities and participation in contractual joint ventures, some of which may involve the extension of loans or other types of financing arrangements. Equity investments, other than those accounted for as equity method investments or those that are proportionately consolidated, are measured at their fair value if their fair values are readily determinable. 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, which is referred to as the “adjusted cost basis.” The Company evaluates its investments for impairment by considering a variety of factors, including the earnings performance of the related investments, as well as the economic environment and market conditions in which the investees operate. Equity Investments The Company’s equity investments as of March 31, 2024 include: (i) the Company’s 33% equity interests in Trans-Pecos Pipeline, LLC (“TPP”) and Comanche Trail Pipeline, LLC (“CTP,” and together with TPP, the “Waha JVs”); (ii) a 15% equity interest in Cross Country Infrastructure Services, Inc. (“CCI”); (iii) the Company’s 50% equity interests in each of FM Technology Holdings, LLC, FM USA Holdings, LLC and All Communications Solutions Holdings, LLC, collectively “FM Tech”; (iv) the Company’s interests in certain proportionately consolidated non-controlled contractual joint ventures; and (v) certain other equity investments. As of March 31, 2024 and December 31, 2023, the aggregate carrying value of the Company’s equity investments, including equity investments measured on an adjusted cost basis, totaled approximately $327 million and $319 million, respectively. As of both March 31, 2024 and December 31, 2023, equity investments measured on an adjusted cost basis, including the Company’s $15 million investment in CCI, totaled approximately $18 million. There were no impairments related to these investments in either of the three month periods ended March 31, 2024 or 2023. The Waha JVs. The Waha JVs own and operate certain pipeline infrastructure that transports natural gas to the Mexican border for export. The Company’s investments in the Waha JVs are accounted for as equity method investments. Equity in earnings related to the Company’s proportionate share of income from the Waha JVs, which is included within the Company’s Other segment, totaled approximately $7.7 million and $8.0 million for the three month periods ended March 31, 2024 and 2023, respectively. Distributions of earnings from the Waha JVs, which are included within operating cash flows, totaled approximately $4.2 million and $4.3 million for the three month periods ended March 31, 2024 and 2023, respectively. Cumulative undistributed earnings from the Waha JVs, which represents cumulative equity in earnings for the Waha JVs less distributions of earnings, totaled $129.1 million as of March 31, 2024. The Company’s net investment in the Waha JVs, which differs from its proportionate share of the net assets of the Waha JVs due primarily to equity method goodwill associated with capitalized investment costs, totaled approximately $280 million and $274 million as of March 31, 2024 and December 31, 2023, respectively. The Waha JVs are party to separate non-recourse financing facilities, each of which are secured by pledges of the equity interests in the respective entities, as well as a first lien security interest over virtually all of their assets. The Waha JVs are also party to certain interest rate swaps (the “Waha JV swaps”), which are accounted for as qualifying cash flow hedges. The Company reflects its proportionate share of any unrealized fair market value gains or losses from fluctuations in interest rates associated with these swaps within other comprehensive income or loss, as appropriate. For the three month period ended March 31, 2024, the Company’s proportionate share of unrecognized unrealized activity on the Waha JV swaps totaled gains of approximately $3.6 million, or $2.7 million, net of tax, and for the three month period ended March 31, 2023, such activity totaled losses of approximately $5.6 million, or $4.2 million, net of tax. Other Investments. The Company has equity interests in certain telecommunications entities that are accounted for as equity method investments. As of March 31, 2024 and December 31, 2023, the Company had an aggregate investment of approximately $22 million and $21 million, respectively, in these entities, including $18 million for FM Tech as of both periods. Certain of these telecommunications entities provide services to MasTec. Expense recognized in connection with services provided by these entities totaled approximately $1.0 million and $0.4 million for the three month periods ended March 31, 2024 and 2023, respectively. As of March 31, 2024 and December 31, 2023, related amounts payable to these entities totaled approximately $0.3 million and $0.1 million, respectively. In addition, the Company had an employee leasing arrangement with one of these entities and has advanced certain amounts to these entities. For the three month period ended March 31, 2024, there were no employee lease expenses related to this arrangement, and advances to these entities totaled approximately $0.1 million. For the three month period ended March 31, 2023, employee lease expenses and advances to these entities were de minimis. As of March 31, 2024 and December 31, 2023, receivables related to these arrangements totaled approximately $4.2 million and $4.0 million, respectively. The Company has 49% equity interests in certain entities included within its Communications and Power Delivery segments that are accounted for as equity method investments, for which its aggregate investment as of both March 31, 2024 and December 31, 2023 totaled approximately $3 million. The above described entities provide construction services to MasTec. Expense recognized in connection with construction services provided by these entities totaled approximately $0.1 million and $0.3 million for the three month periods ended March 31, 2024 and 2023, respectively. As of both March 31, 2024 and December 31, 2023, related amounts payable were de minimis. In addition, the Company provides line of credit arrangements to these entities, which, as of both March 31, 2024 and December 31, 2023, provide for up to $3.0 million of borrowing availability, for which there were no borrowings as of March 31, 2024 or December 31, 2023. The Company has a 75% equity interest in Confluence Networks, LLC (“Confluence”), an undersea fiber-optic communications systems developer. MasTec does not have a majority voting or controlling financial interest in Confluence, but does have the ability to exert significant influence, and therefore, accounts for its interest as an equity method investment. As of March 31, 2024, approximately $2.1 million of MasTec’s $2.5 million initial commitment had been funded, of which $0.1 million and $0.2 million was funded during the three month periods ended March 31, 2024 and 2023, respectively. Variable Interest Entities. The Company has determined that certain of its investment arrangements are variable interest entities (“VIEs”). Management assesses its VIEs on an ongoing basis to determine if the Company is the primary beneficiary and if consolidation is required. As of March 31, 2024, management determined that the Company is the primary beneficiary of two of its VIEs, and accordingly, has consolidated these entities within the Company’s financial statements, with the other parties’ interests accounted for as a non-controlling interests. The Company’s consolidated VIEs include an electric utility contractor in which the Company acquired a 49% interest in the first quarter of 2024. As of March 31, 2024 and December 31, 2023, the carrying values of assets associated with the Company’s consolidated VIEs totaled approximately $16.1 million and $1.7 million, respectively, which amounts consisted primarily of accounts receivable, net of allowance and cash. The carrying values of liabilities associated with the Company’s consolidated VIEs totaled approximately $14.4 million and $1.6 million as of March 31, 2024 and December 31, 2023, respectively, which amounts consisted primarily of accounts payable and accrued salaries and wages. The Company has not provided, nor is it obligated to provide, any financial support to any of its consolidated VIEs. The carrying values of the Company’s VIEs that are not consolidated totaled approximately $24 million and $23 million as of March 31, 2024 and December 31, 2023, respectively, which amounts are recorded within other long-term assets in the consolidated balance sheets. Management believes that the Company’s maximum exposure to loss for its non-consolidated VIEs, inclusive of additional financing commitments, approximated $36 million and $35 million as of March 31, 2024 and December 31, 2023, respectively. Senior Notes As of both March 31, 2024 and December 31, 2023, the gross carrying amount of the Company’s 4.50% senior notes due August 15, 2028 (the “4.50% Senior Notes”) totaled $600.0 million, and their estimated fair value totaled approximately $570.6 million and $565.2 million for the respective periods. As of March 31, 2024 and December 31, 2023, the gross carrying amount of the Company’s 6.625% senior notes due August 15, 2029 (the “6.625% Senior Notes,” and together with the 4.50% Senior Notes, the “Senior Notes”) totaled $284.9 million and $284.2 million, respectively, and their estimated fair value totaled approximately $280.2 million and $273.9 million for the respective periods. As of March 31, 2024, the estimated fair values of the Company’s Senior Notes were determined based on an exit price approach using Level 2 inputs. In the first quarter of 2024, management reevaluated its fair value hierarchy determination for its Senior Notes. As a result of this evaluation, management updated its hierarchy Level determination for its Senior Notes from Level 1 inputs to Level 2 inputs to better align with the valuation hierarchy within the fair value guidance, which update had no effect on the reported fair values of the related Senior Notes.

The Company’s financial instruments are primarily composed of cash and cash equivalents, accounts receivable and contract assets, notes receivable, cash collateral deposited with insurance carriers, life insurance assets, equity investments, certain other assets and investments, deferred compensation plan assets and liabilities, accounts payable and other current liabilities, acquisition-related contingent consideration and other liabilities, and debt obligations.

Fair value is the price that would be received to sell an asset or the amount paid to transfer a liability, also referred to as the “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, including quoted market prices for identical or similar assets or liabilities in markets that are not active; 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.

Acquisition-related contingent consideration is composed of earn-outs, which represent the estimated fair value of future amounts payable for businesses, which we refer to as “Earn-outs,” that are contingent upon the acquired businesses achieving certain levels of earnings in the future. As of March 31, 2024 and December 31, 2023, the estimated fair value of the Company’s Earn-out liabilities totaled $71.3 million and $77.4 million, respectively. Earn-out liabilities included within other current liabilities totaled approximately $24.4 million and $29.8 million as of March 31, 2024 and December 31, 2023, respectively. The fair values of the Company’s Earn-out liabilities are estimated using income approaches such as discounted cash flows or option pricing models, both of which incorporate significant inputs not observable in the market (Level 3 inputs), including management’s estimates and entity-specific assumptions, and are evaluated on an ongoing basis. Key assumptions include the discount rate, which was 14.0% as of March 31, 2024, and probability-weighted projections of EBITDA. Significant changes in any of these assumptions could result in significantly higher or lower potential Earn-out liabilities. The ultimate payment amounts for the Company’s Earn-out liabilities will be determined based on the actual results achieved by the acquired businesses. As of March 31, 2024, the range of potential undiscounted Earn-out liabilities was estimated to be between $23 million and $86 million; however, there is no maximum payment amount.

Earn-out activity consists primarily of additions from new business combinations; changes in the expected fair value of future payment obligations; and payments. For both the three month periods ended March 31, 2024 and 2023, there were no additions from new business combinations or measurement period adjustments. For the three month period ended March 31, 2024, fair value adjustments totaled a decrease, net, of approximately $6.1 million primarily related to acquisitions within the Company’s Communications segment. For the three month period ended March 31, 2023, fair value adjustments totaled a decrease, net, of approximately $0.3 million, including decreases related to acquisitions within the Company’s Communications and Clean Energy and Infrastructure segments, which were largely offset by an increase related to acquisitions within the Company’s Oil and Gas segment. There were no Earn-out payments for the three month period ended March 31, 2024, and for the three month period ended March 31, 2023, Earn-out payments totaled approximately $1.7 million and related to a mandatorily redeemable non-controlling interest arrangement that was completed in 2023.

From time to time, the Company may participate in selected investment or strategic arrangements, including equity interests in various business entities and participation in contractual joint ventures, some of which may involve the extension of loans or other types of financing arrangements. Equity investments, other than those accounted for as equity method investments or those that are proportionately consolidated, are measured at their fair value if their fair values are readily determinable. 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, which is referred to as the “adjusted cost basis.” The Company evaluates its investments for impairment by considering a variety of factors, including the earnings performance of the related investments, as well as the economic environment and market conditions in which the investees operate.

The Company’s equity investments as of March 31, 2024 include: (i) the Company’s 33% equity interests in Trans-Pecos Pipeline, LLC (“TPP”) and Comanche Trail Pipeline, LLC (“CTP,” and together with TPP, the “Waha JVs”); (ii) a 15% equity interest in Cross Country Infrastructure Services, Inc. (“CCI”); (iii) the Company’s 50% equity interests in each of FM Technology Holdings, LLC, FM USA Holdings, LLC and All Communications Solutions Holdings, LLC, collectively “FM Tech”; (iv) the Company’s interests in certain proportionately consolidated non-controlled contractual joint ventures; and (v) certain other equity investments.

As of March 31, 2024 and December 31, 2023, the aggregate carrying value of the Company’s equity investments, including equity investments measured on an adjusted cost basis, totaled approximately $327 million and $319 million, respectively. As of both March 31, 2024 and December 31, 2023, equity investments measured on an adjusted cost basis, including the Company’s $15 million investment in CCI, totaled

The Waha JVs. The Waha JVs own and operate certain pipeline infrastructure that transports natural gas to the Mexican border for export. The Company’s investments in the Waha JVs are accounted for as equity method investments. Equity in earnings related to the Company’s proportionate share of income from the Waha JVs, which is included within the Company’s Other segment, totaled approximately $7.7 million and $8.0 million for the three month periods ended March 31, 2024 and 2023, respectively. Distributions of earnings from the Waha JVs, which are included within operating cash flows, totaled approximately $4.2 million and $4.3 million for the three month periods ended March 31, 2024 and 2023, respectively. Cumulative undistributed earnings from the Waha JVs, which represents cumulative equity in earnings for the Waha JVs less distributions of earnings, totaled $129.1 million as of March 31, 2024. The Company’s net investment in the Waha JVs, which differs from its proportionate share of the net assets of the Waha JVs due primarily to equity method goodwill associated with capitalized investment costs, totaled approximately $280 million and $274 million as of March 31, 2024 and December 31, 2023, respectively.

The Waha JVs are party to separate non-recourse financing facilities, each of which are secured by pledges of the equity interests in the respective entities, as well as a first lien security interest over virtually all of their assets. The Waha JVs are also party to certain interest rate swaps (the “Waha JV swaps”), which are accounted for as qualifying cash flow hedges. The Company reflects its proportionate share of any unrealized fair market value gains or losses from fluctuations in interest rates associated with these swaps within other comprehensive income or loss, as appropriate. For the three month period ended March 31, 2024, the Company’s proportionate share of unrecognized unrealized activity on the Waha JV swaps totaled gains of approximately $3.6 million, or $2.7 million, net of tax, and for the three month period ended March 31, 2023, such activity totaled losses of approximately $5.6 million, or $4.2 million, net of tax.

Other Investments. The Company has equity interests in certain telecommunications entities that are accounted for as equity method investments. As of March 31, 2024 and December 31, 2023, the Company had an aggregate investment of approximately $22 million and $21 million, respectively, in these entities, including $18 million for FM Tech as of both periods.

Certain of these telecommunications entities provide services to MasTec. Expense recognized in connection with services provided by these entities totaled approximately $1.0 million and $0.4 million for the three month periods ended March 31, 2024 and 2023, respectively. As of March 31, 2024 and December 31, 2023, related amounts payable to these entities totaled approximately $0.3 million and $0.1 million, respectively. In addition, the Company had an employee leasing arrangement with one of these entities and has advanced certain amounts to these entities. For the three month period ended March 31, 2024, there were no employee lease expenses related to this arrangement, and advances to these entities totaled approximately $0.1 million. For the three month period ended March 31, 2023, employee lease expenses and advances to these entities were de minimis. As of March 31, 2024 and December 31, 2023, receivables related to these arrangements totaled approximately $4.2 million and $4.0 million, respectively.

The Company has 49% equity interests in certain entities included within its Communications and Power Delivery segments that are accounted for as equity method investments, for which its aggregate investment as of both March 31, 2024 and December 31, 2023 totaled approximately $3 million. The above described entities provide construction services to MasTec. Expense recognized in connection with construction services provided by these entities totaled approximately $0.1 million and $0.3 million for the three month periods ended March 31, 2024 and 2023, respectively. As of both March 31, 2024 and December 31, 2023, related amounts payable were de minimis. In addition, the Company provides line of credit arrangements to these entities, which, as of both March 31, 2024 and December 31, 2023, provide for up to $3.0 million of borrowing availability, for which there were no borrowings as of March 31, 2024 or December 31, 2023.

The Company has a 75% equity interest in Confluence Networks, LLC (“Confluence”), an undersea fiber-optic communications systems developer. MasTec does not have a majority voting or controlling financial interest in Confluence, but does have the ability to exert significant influence, and therefore, accounts for its interest as an equity method investment. As of March 31, 2024, approximately $2.1 million of MasTec’s $2.5 million initial commitment had been funded, of which $0.1 million and $0.2 million was funded during the three month periods ended March 31, 2024 and 2023, respectively.

Variable Interest Entities. The Company has determined that certain of its investment arrangements are variable interest entities (“VIEs”). Management assesses its VIEs on an ongoing basis to determine if the Company is the primary beneficiary and if consolidation is required. As of March 31, 2024, management determined that the Company is the primary beneficiary of two of its VIEs, and accordingly, has consolidated these entities within the Company’s financial statements, with the other parties’ interests accounted for as a non-controlling interests.

The Company’s consolidated VIEs include an electric utility contractor in which the Company acquired a 49% interest in the first quarter of 2024. As of March 31, 2024 and December 31, 2023, the carrying values of assets associated with the Company’s consolidated VIEs totaled approximately $16.1 million and $1.7 million, respectively, which amounts consisted primarily of accounts receivable, net of allowance and cash. The carrying values of liabilities associated with the Company’s consolidated VIEs totaled approximately $14.4 million and $1.6 million as of March 31, 2024 and December 31, 2023, respectively, which amounts consisted primarily of accounts payable and accrued salaries and wages. The Company has not provided, nor is it obligated to provide, any financial support to any of its consolidated VIEs.

The carrying values of the Company’s VIEs that are not consolidated totaled approximately $24 million and $23 million as of March 31, 2024 and December 31, 2023, respectively, which amounts are recorded within other long-term assets in the consolidated balance sheets. Management believes that the Company’s maximum exposure to loss for its non-consolidated VIEs, inclusive of additional financing commitments, approximated $36 million and $35 million as of March 31, 2024 and December 31, 2023, respectively.

As of both March 31, 2024 and December 31, 2023, the gross carrying amount of the Company’s 4.50% senior notes due August 15, 2028 (the “4.50% Senior Notes”) totaled $600.0 million, and their estimated fair value totaled approximately $570.6 million and $565.2 million for the respective periods. As of March 31, 2024 and December 31, 2023, the gross carrying amount of the Company’s 6.625% senior notes due August 15,