Segments and Related Information (Descriptions) (Narrative) (Details)	9 Months Ended
	Sep. 30, 2014 segment
Segments and Related Information [Line Items]
Segment reporting information, factors used to identify entity's reportable segments	MasTec presents its continuing operations in five reportable segments: (1) Communications; (2) Oil and Gas; (3) Electrical Transmission; (4) Power Generation and Industrial and (5) Other. This structure is generally focused on broad end-user markets for MasTec's labor-based construction services.
Number of reportable segments	5
Segment reporting information, description of products and services	All five reportable segments derive their revenues from the engineering, installation and maintenance of infrastructure, primarily in North America.
Segment reporting, description of all other segments	The Other segment primarily includes small business units that perform construction services for a variety of end markets in Mexico and elsewhere internationally.
Reportable Segments [Member] | Communications [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	The Communications segment performs engineering, construction and maintenance of communications infrastructure primarily related to wireless and wireline/fiber communications and install-to-the-home customers, and, to a lesser extent, infrastructure for electrical utilities.
Reportable Segments [Member] | Oil and Gas [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	MasTec performs engineering, construction and maintenance services on oil and natural gas pipelines and processing facilities for the energy and utilities industries through its Oil and Gas segment.
Reportable Segments [Member] | Electrical Transmission [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	The Electrical Transmission segment primarily serves the energy and utility industries through the engineering, construction and maintenance of electrical transmission lines and substations.
Reportable Segments [Member] | Power Generation and Industrial [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	The Power Generation and Industrial segment primarily serves energy, utility and other end-markets through the installation and construction of conventional and renewable power facilities, related electrical transmission infrastructure, ethanol facilities and various types of industrial infrastructure.