Subsequent Events (Narrative) (Details) (Revolving Credit Facility [Member]) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 USD ($)	Sep. 30, 2013 Subsequent Event [Member]	Oct. 29, 2013 Subsequent Event [Member] USD ($)	Oct. 29, 2013 Subsequent Event [Member] CAD	Sep. 30, 2013 Maximum [Member] USD ($)	Oct. 29, 2013 Maximum [Member] Subsequent Event [Member] USD ($)	Sep. 30, 2013 Letter of Credit [Member] Maximum [Member] USD ($)	Oct. 29, 2013 Letter of Credit [Member] Maximum [Member] Subsequent Event [Member] USD ($)
Subsequent Event [Line Items]
Subsequent event, description	On October 29, 2013, MasTec entered into an amendment (the “Amendment”) to its Credit Facility, which, among other things, extended the maturity to October 2018 and increased the revolving commitments available from $600 million to $750 million, of which up to $100 million may be borrowed in Canadian dollars.  Additionally, the Amendment increased the amount available for letters of credit from $350 million to $450 million and the amount available for swing line loans from $50 million to $75 million.  The Amendment also reduced the rates applicable to the commitments, borrowings and letters of credit under the Credit Facility.
Line of credit facility, maximum borrowing capacity	$ 600		$ 750	100
Line of credit facility, expiration date	Aug. 22, 2016	Oct. 31, 2018
Line of credit facility, capacity available for issuance of letters of credit							350.0	450.0
Line of credit facility, capacity available for swing loans					$ 50	$ 75