Acquisitions and Other Investments Acquisitions and Other Investments (Schedule of Business Acquisition Pro Forma Information) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
2011 Acquisitions [Member]
Business Acquisition [Line Items]
Business acquisition, pro forma information, description	The unaudited pro forma combined results of operations for the years ended December 31, 2011 and 2010 have been prepared by adjusting the historical results of MasTec to include the historical results of the acquisitions described above as if they occurred January 1, 2010. These pro forma combined historical results were then adjusted for an increase in amortization expense due to the incremental intangible assets recorded related to the acquisitions and the reduction of interest income as a result of the cash consideration paid. The pro forma results of operations do not include any adjustments to eliminate the impact of acquisition related costs or any cost savings or other synergies that may result from these acquisitions. As noted above, the pro forma results of operations do not purport to be indicative of the actual results that would have been achieved by the combined company for the periods presented or that may be achieved by the combined company in the future.
Business acquisition, pro forma revenue		$ 3,115.6	$ 2,506.0
Business acquisition, pro forma net income (loss)		105.5	85.6
2012 Acquisitions [Member]
Business Acquisition [Line Items]
Business acquisition, pro forma information, description	The unaudited pro forma combined results of operations for the years ended December 31, 2012 and 2011 have been prepared by adjusting the historical results of MasTec to include the historical results of the acquisitions described above as if they occurred January 1, 2011. These pro forma combined historical results were then adjusted for an increase in amortization expense due to the incremental intangible assets recorded related to the acquisitions and the reduction of interest income as a result of the cash consideration paid. The pro forma results of operations do not include any adjustments to eliminate the impact of acquisition related costs or any cost savings or other synergies that may result from these acquisitions. As noted above, the pro forma results of operations do not purport to be indicative of the actual results that would have been achieved by the combined company for the periods presented or that may be achieved by the combined company in the future.
Business acquisition, pro forma revenue	3,879.1	2,931.1
Business acquisition, pro forma net income (loss)	119.4	$ 112.3