Commitments and Contingencies - Other (Narrative) (Details) (USD $) In Millions, unless otherwise specified													0 Months Ended				12 Months Ended
	Dec. 31, 2013 Uninsured Risk [Member] Other Noncurrent Assets [Member]	Dec. 31, 2012 Uninsured Risk [Member] Other Noncurrent Assets [Member]	Dec. 31, 2013 Uninsured Risk [Member] Workers Compensation, General And Automobile Policies [Member]	Dec. 31, 2012 Uninsured Risk [Member] Workers Compensation, General And Automobile Policies [Member]	Dec. 31, 2013 Uninsured Risk [Member] Employee Group Health Claims Policy [Member]	Dec. 31, 2012 Uninsured Risk [Member] Employee Group Health Claims Policy [Member]	Dec. 31, 2013 Standby Letters of Credit [Member] Uninsured Risk [Member]	Dec. 31, 2012 Standby Letters of Credit [Member] Uninsured Risk [Member]	Dec. 31, 2013 Guarantee Obligations [Member] Letter of Credit [Member]	Dec. 31, 2012 Guarantee Obligations [Member] Letter of Credit [Member]	Dec. 31, 2013 Performance Guarantee [Member]	Dec. 31, 2012 Performance Guarantee [Member]	Dec. 31, 2013 Performance Guarantee [Member] Estimate [Member]	Dec. 31, 2012 Performance Guarantee [Member] Estimate [Member]	Dec. 31, 2013 Surety Bond [Member] Uninsured Risk [Member]	Dec. 31, 2012 Surety Bond [Member] Uninsured Risk [Member]	Dec. 31, 2013 Subsidiary Issuer [Member]
Loss Contingencies [Line Items]
Letters of credit, outstanding amount							$ 57.4	$ 53.2	$ 134.8	$ 120.8
Outstanding bonds, amount											1,000.0	1,100.0			10.9	9.0
Estimated cost to complete bonded projects													297.1	287.7
Self insurance reserve			50.8	48.1	2.1	1.1
Self insurance reserve, noncurrent			31.3	28.5
Cash collateral held by insurance carriers	$ 1.4	$ 1.4
Other guarantees, description																	In the ordinary course of its business, from time to time, MasTec guarantees the obligations of its subsidiaries, including obligations under certain contracts with customers, certain lease obligations and in some states, obligations in connection with obtaining contractors’ licenses.