Other Retirement Plans (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016
Multiemployer Plans [Line Items]
Multiemployer plans, general nature	certain of MasTec’s subsidiaries are party to various collective bargaining agreements with unions representing certain of their employees, which require the Company to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to MEPPs.
Pension [Member]
Multiemployer Plans [Line Items]
Multiemployer plans, underfunded status, description	A multiemployer plan that is so underfunded as to be in “endangered,” “seriously endangered,” “critical,” or “critical and declining” status (as determined under the PPA) is required to adopt a funding improvement plan (“FIP”) or a rehabilitation plan (“RP”), which, among other actions, could include decreased benefits and increased employer contributions, which could take the form of a surcharge on benefit contributions. These actions are intended to improve their funding status over a period of years. If a pension fund is in critical status, a participating employer must pay an automatic surcharge in addition to contributions otherwise required under the collective bargaining agreement (“CBA”). With some exceptions, the surcharge is equal to 5% of required contributions for the initial critical year and 10% for each succeeding plan year in which the plan remains in critical status. The surcharge ceases on the effective date of a CBA (or other agreement) that includes contribution and benefit terms consistent with the rehabilitation plan. Certain plans in which the Company participates are in “endangered,” “seriously endangered,” “critical,” or “critical and declining” status. The amount of additional funds, if any, that the Company may be obligated to contribute to these plans in the future cannot be estimated due to the uncertainty of the future levels of work that could be required of the union employees covered by these plans, as well as the required future contribution rates and possible surcharges applicable to these plans.