Commitments and Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended										0 Months Ended						3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Uninsured Risk [Member] Other Non-Current Assets [Member]	Dec. 31, 2013 Uninsured Risk [Member] Other Non-Current Assets [Member]	Mar. 31, 2014 Uninsured Risk [Member] Workers Compensation, General And Automobile Policies [Member]	Dec. 31, 2013 Uninsured Risk [Member] Workers Compensation, General And Automobile Policies [Member]	Mar. 31, 2014 Uninsured Risk [Member] Group Insurance Policies [Member] Health Insurance [Member]	Dec. 31, 2013 Uninsured Risk [Member] Group Insurance Policies [Member] Health Insurance [Member]	Mar. 31, 2014 Performance Standby [Member]	Dec. 31, 2013 Performance Standby [Member]	Mar. 31, 2014 Performance Standby [Member] Plan [Member]	Dec. 31, 2013 Performance Standby [Member] Plan [Member]	Mar. 31, 2014 Financial Standby [Member] Uninsured Risk [Member]	Dec. 31, 2013 Financial Standby [Member] Uninsured Risk [Member]	Mar. 31, 2014 Surety Bond [Member] Uninsured Risk [Member] Workers Compensation [Member]	Dec. 31, 2013 Surety Bond [Member] Uninsured Risk [Member] Workers Compensation [Member]	Mar. 31, 2014 Subsidiary [Member]	Mar. 31, 2014 Pending Litigation [Member] Sunlight Entities [Member]	Mar. 31, 2014 Pending Litigation [Member] Sunlight Entities [Member] Construction Contracts [Member]	Mar. 31, 2014 Pending Litigation [Member] Sunlight General Somerset [Member]	Mar. 31, 2014 Pending Litigation [Member] Sunlight General Morris [Member]	Mar. 31, 2014 Pending Litigation [Member] Sunlight General Sussex [Member]
Commitments and Contingencies [Line Items]
Pending litigation, number																		3	3
Contract price, pending litigation																				$ 29	$ 36	$ 26
Liens sought, pending litigation																		50
Letters of credit, outstanding amount	134.7	134.8											57.4	57.4
Outstanding bonds, amount									1,000.0	1,100.0					10.9	10.9
Estimated cost to complete bonded projects											281.6	297.1
Self insurance reserve					50.9	50.8	1.9	2.1
Self insurance reserve, non-current					32.0	31.3
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.
General warranty, description	MasTec also generally warrants the work it performs for a one to two year period following substantial completion of a project.