Acquisitions (Schedule of Pro Forma Information, Business Acquisitions) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Business Combinations [Line Items]
Business combinations, pro forma information, description					The unaudited supplemental pro forma financial information presented below has been prepared by adjusting the historical results of MasTec to include the historical results of the acquired businesses described above. The unaudited supplemental pro forma combined historical results were then adjusted (i) to remove one-time acquisition costs; (ii) to increase amortization expense resulting from the incremental intangible assets acquired in such acquisitions; (iii) to increase interest expense as a result of the cash consideration paid; and (iv) to reduce interest expense from the repayment of acquired debt. The unaudited supplemental pro forma financial information does not include any adjustments to reflect the impact of cost savings or other synergies that may result from these acquisitions. As noted above, the unaudited supplemental pro forma financial information does not purport to be indicative of the actual results that would have been achieved by the combined companies for the periods presented or that may be achieved by the combined companies in the future.
Business combinations, pro forma revenue	$ 1,309.6		$ 1,417.5		$ 3,496.0		$ 3,667.3
Business combinations, pro forma net income from continuing operations	46.0		52.4		96.5		118.0
Business combinations, acquiree revenue, year over year incremental impact	133.2		141.6		342.5		270.4
Business combinations, acquiree net income from continuing operations, year over year incremental impact	2.3	[1]	7.5	[1]	4.5	[1]	12.8	[1]
General and Administrative Costs [Member]
Business Combinations [Line Items]
Business combinations, acquisition costs	$ 0.4		$ 0.3		$ 2.0		$ 1.6

[1] The above results do not include acquisition costs totaling $0.4 million and $0.3 million for the three month periods ended September 30, 2014 and 2013, respectively, and $2.0 million and $1.6 million for the nine month periods ended September 30, 2014 and 2013, respectively. Acquisition costs are included within general and administrative costs in the Company's consolidated unaudited statements of operations. The above results also do not include interest expense associated with consideration paid for these acquisitions.