Business, Basis of Presentation and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]
Nature of the Business	Nature of the Business MasTec, Inc. (collectively with its subsidiaries, “MasTec” or the “Company”) is a leading infrastructure construction company operating mainly throughout North America across a range of industries. The Company’s primary activities include the engineering, building, installation, maintenance and upgrade of energy, utility and communications infrastructure, such as: petroleum and natural gas pipeline infrastructure; wireless, wireline/fiber and satellite communications; electrical utility transmission and distribution; power generation; and industrial infrastructure. MasTec’s customers are in these industries. MasTec reports its results in five reportable segments: (1) Communications; (2) Oil and Gas; (3) Electrical Transmission; (4) Power Generation and Industrial; and (5) Other. See Note 15 - Segments and Related Information.
Basis of Presentation	Basis of Presentation The accompanying condensed unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X. Pursuant to these rules and regulations, certain information and footnote disclosures normally included in the annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The accompanying condensed consolidated balance sheet as of December 31, 2013 is derived from the Company’s audited financial statements as of that date. Because certain information and footnote disclosures have been condensed or omitted, these condensed unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto as of and for the year ended December 31, 2013 contained in the Company’s most recent Annual Report on Form 10-K. In management’s opinion, all normal and recurring adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented have been included. Certain prior year amounts have been reclassified to conform to the current period presentation. Interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. The Company believes that the disclosures made in these condensed unaudited consolidated financial statements are adequate to make the information not misleading.
Reclassifications	Certain prior year amounts have been reclassified to conform to the current period presentation.
Principles of Consolidation	Principles of Consolidation The accompanying condensed unaudited 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. Other parties’ interests in companies for which MasTec exercises control and has a controlling financial interest are reported as non-controlling interests within equity. Net income or loss attributable to non-controlling interests is reported as a separate line item below net income. The Company’s investments in entities in which the Company does not have a controlling interest, but has the ability to exert significant influence, are accounted for using the equity method of accounting. Equity method investments are recorded as long-term assets in the condensed unaudited consolidated balance sheets. Income or loss from these investments is recorded in other income or expense, net, in the condensed unaudited consolidated statements of operations. The Company's investments in entities in which the Company does not have the ability to exert significant influence are accounted for using the cost method of accounting. All significant intercompany balances and transactions have been eliminated in consolidation. The assets and liabilities of foreign subsidiaries are translated into U.S. dollars at period-end exchange rates, with resulting translation gains or losses accumulated within other comprehensive income or loss. Revenue and expenses are translated into U.S. dollars at average rates of exchange prevailing during the applicable period. Gains or losses resulting from transactions executed in a foreign currency are included in other income or expense, net. The Company does not currently have any subsidiaries that operate in highly inflationary environments. The results of operations and financial position of any discontinued operations are aggregated and presented separately from the Company's continuing operations in the condensed unaudited consolidated financial statements for all periods presented.
Translation of Foreign Currencies	The assets and liabilities of foreign subsidiaries are translated into U.S. dollars at period-end exchange rates, with resulting translation gains or losses accumulated within other comprehensive income or loss. Revenue and expenses are translated into U.S. dollars at average rates of exchange prevailing during the applicable period. Gains or losses resulting from transactions executed in a foreign currency are included in other income or expense, net. The Company does not currently have any subsidiaries that operate in highly inflationary environments.
Investments in Affiliates and Other Entities	Investments in Affiliates and Other Entities In the ordinary course of business, the Company enters into various investment arrangements, which may include equity or other interests in business entities, including contractual joint ventures or other forms of equity participation. These investment arrangements may also include certain forms of financing, such as the extension of loans. In connection with certain of these investment arrangements, the Company provides infrastructure construction services to or through its equity investees and/or contractual joint ventures. Management determines whether such investment arrangements involve a variable interest entity (“VIE”) based on the characteristics of the particular entity. If an entity is determined to be a VIE, then management determines if the Company is the primary beneficiary of the entity and whether or not consolidation of the VIE within the Company's financial statements is required. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the activities of a VIE that most significantly affect the VIE’s economic performance 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. If management determines that the Company is the primary beneficiary of a VIE, then the VIE would be consolidated, and the other party’s equity interest in the VIE would be accounted for as a non-controlling interest. As of September 30, 2014, the Company was not the primary beneficiary of any VIE. In cases where the Company has an undivided interest in the assets, liabilities, revenues and profits of an unincorporated entity, such amounts are consolidated on a basis proportional to the Company’s ownership interest in the unincorporated entity.
Variable Interest Entities	In the ordinary course of business, the Company enters into various investment arrangements, which may include equity or other interests in business entities, including contractual joint ventures or other forms of equity participation. These investment arrangements may also include certain forms of financing, such as the extension of loans. In connection with certain of these investment arrangements, the Company provides infrastructure construction services to or through its equity investees and/or contractual joint ventures. Management determines whether such investment arrangements involve a variable interest entity (“VIE”) based on the characteristics of the particular entity. If an entity is determined to be a VIE, then management determines if the Company is the primary beneficiary of the entity and whether or not consolidation of the VIE within the Company's financial statements is required. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the activities of a VIE that most significantly affect the VIE’s economic performance 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. If management determines that the Company is the primary beneficiary of a VIE, then the VIE would be consolidated, and the other party’s equity interest in the VIE would be accounted for as a non-controlling interest.
Unincorporated Joint Ventures, Proportionate Consolidation	In cases where the Company has an undivided interest in the assets, liabilities, revenues and profits of an unincorporated entity, such amounts are consolidated on a basis proportional to the Company’s ownership interest in the unincorporated entity.
Management Estimates	Management Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Key estimates include: the recognition of revenue and gross profit or loss, in particular, on long-term construction contracts, which rely upon estimates of costs to complete projects, ultimate project gross profit and the amount of contract price adjustments that are probable; allowances for doubtful accounts; accrued self-insured claims; estimated fair values of goodwill and intangible assets, acquisition-related contingent consideration, convertible debt obligations and investments in cost and equity method investees; asset lives used in computing depreciation and amortization, including amortization of intangible assets; share-based compensation; accounting for income taxes; and the estimated impact of contingencies and ongoing litigation. While management believes that such estimates are fair when considered in conjunction with the consolidated financial position and results of operations taken as a whole, actual results could differ from those estimates and such differences may be material to the condensed unaudited consolidated financial statements.
Revenue Recognition	Revenue Recognition Revenues are derived from projects performed under master and other service agreements as well as from fixed price contracts for specific projects or jobs requiring the construction and installation of an entire infrastructure system or specified units within an entire infrastructure system. Revenue and related costs for master and other service agreements billed on a time and materials basis are recognized as the services are rendered. The Company also performs services under master and other service agreements on a fixed fee basis, under which MasTec furnishes specified units of service for a fixed price per unit of service and revenue is recognized as the services are rendered. Revenues from fixed price contracts provide for a fixed amount of revenue for the entire project, subject to certain additions for changed scope or specifications. Revenues from these contracts are recognized using the percentage-of-completion method. Under this method, the percentage of revenue to be recognized for a given project is measured by the percentage of costs incurred to date on the contract to the total estimated costs for the contract. Such contracts provide that the customer accept completion of progress to date and compensate the Company for services rendered, which may be measured in terms of costs incurred, units installed, hours expended or some other measure of progress. The Company may incur costs subject to change orders, whether approved or unapproved by the customer, and/or claims related to certain contracts. Management determines the probability that such costs will be recovered based upon evidence such as engineering studies and legal opinions, past practices with the customer, specific discussions, correspondence or preliminary negotiations with the customer. The Company treats project costs as a cost of contract performance in the period incurred if it is not probable that the costs will be recovered, or defers costs and/or recognizes revenue up to the amount of the related cost if it is probable that the contract price will be adjusted and can be reliably estimated. As of September 30, 2014 and December 31, 2013, the Company had approximately $78 million and $79 million, respectively, of change orders and/or claims that had been included as contract price adjustments on certain contracts that were in the process of being resolved in the normal course of business, including through negotiation, in arbitration and other proceedings. These contract price adjustments represent management's best estimate of additional contract revenues that have been or will be earned and that management believes are probable of collection. The amounts ultimately realized upon final acceptance by its customers could be higher or lower than such estimated amounts, which are primarily expected to be billed and collected within one year.
New Accounting Pronouncements	New Accounting Pronouncements Accounting Standards Not Yet Adopted In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606). The core principle of this ASU is that a company will recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under current guidance and will be required to disclose information about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including disclosure of assumptions and estimates where significant judgment has been applied. ASU 2014-09 is effective using either the retrospective or cumulative effect transition method for fiscal years, and interim periods within those years, beginning after December 15, 2016. Early application is not permitted. The Company is currently evaluating the potential impact of this ASU on its consolidated financial statements. In April 2014, the FASB issued ASU 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity (“ASU 2014-08”). ASU 2014-08 changes the requirements for reporting discontinued operations and requires additional disclosures about discontinued operations. Only disposals of components of an entity representing a strategic shift that has, or will have, a major effect on an entity’s operations and financial results should be reported as discontinued operations under ASU 2014-08. Examples include a disposal of a major geographical area, a major line of business, or a major equity method investment. ASU 2014-08 also requires expanded disclosures about discontinued operations and requires disclosures about individually significant dispositions that do not qualify as discontinued operations. ASU 2014-08 is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2014. Early adoption is permitted only for disposals that have not been previously reported. The Company is currently evaluating the potential impact of this ASU on its consolidated financial statements. Recently Adopted Accounting Pronouncements In July 2013, the FASB issued ASU 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (a consensus of the FASB Emerging Issues Task Force) (“ASU 2013-11”). ASU 2013-11 provides guidance on the presentation in the financial statements of an unrecognized tax benefit, or a portion of an unrecognized tax benefit, and explains that unrecognized tax benefits should be presented as a reduction to deferred tax assets for net operating loss carryforwards, similar tax losses or tax credit carryforwards. To the extent a net operating loss carryforward, similar tax loss or tax credit carryforward is not available as of the reporting date under the tax law of the applicable jurisdiction, or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. ASU 2013-11 applies to all entities that have unrecognized tax benefits when a net operating loss carryforward, similar tax loss, or tax credit carryforward exists as of the reporting date. ASU 2013-11 is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. Retrospective application is permitted. The Company adopted ASU 2013-11 as of January 1, 2014. The adoption of this ASU did not have a material impact on the condensed unaudited consolidated financial statements.