Other Retirement Plans (Narrative) (Details)	9 Months Ended
Sep. 30, 2015
Multiemployer Plans [Abstract]
Multi-employer plans, general nature	Certain of MasTec’s subsidiaries, including certain subsidiaries in Canada, contribute amounts to multi-employer pension and other multi-employer benefit plans and trusts, which 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. Multi-employer plan contribution rates are determined annually and assessed on a “pay-as-you-go” basis based on union employee payrolls. 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.

Description of the general nature of multiemployer plans and of the employer's participation in those plans that would indicate how the risks of participating in these plans are different from single-employer plans. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 80

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=49170332&loc=SL14450655-114947

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