Earnings Per Share (Methodology) (Narrative) (Details)	12 Months Ended
Dec. 31, 2014
Earnings Per Share [Line Items]
Computation of earnings per share, methodology	Basic earnings per share is computed by dividing net income or loss available to MasTec’s common shareholders by the weighted average number of common shares outstanding for the period. Diluted earnings per share is computed by dividing net income or loss available to MasTec’s common shareholders by the number of fully diluted shares, which includes the effect of dilutive potential issuances of common shares as determined using earnings from continuing operations, including the potential issuance of common shares upon the exercise, conversion or vesting of outstanding stock options and unvested restricted shares, as calculated under the treasury stock method, as well as shares associated with the Company’s convertible debt securities, which matured and were converted in 2014.
Convertible Debt [Member] \| 2009 Convertible Notes [Member]
Earnings Per Share [Line Items]
Computation of earnings per share, methodology	Until their maturity in 2014, dilutive shares associated with the 2009 Convertible Notes were attributable to the underlying principal amounts and were reflected in the calculation of weighted average diluted earnings per share for the corresponding periods by application of the “if-converted” method.
Convertible Debt [Member] \| 2011 Convertible Notes [Member]
Earnings Per Share [Line Items]
Computation of earnings per share, methodology	The 2011 Convertible Notes had an optional cash settlement feature, which allowed the Company to settle the principal amount in cash. Until their maturity in 2014, dilutive shares associated with the 2011 Convertible Notes were derived from the premium value of the notes in excess of their principal amounts, as calculated using the treasury stock method. These shares were referred to as “premium shares.”

Computation of earnings per share, methodology

Basic earnings per share is computed by dividing net income or loss available to MasTec’s common shareholders by the weighted average number of common shares outstanding for the period. Diluted earnings per share is computed by dividing net income or loss available to MasTec’s common shareholders by the number of fully diluted shares, which includes the effect of dilutive potential issuances of common shares as determined using earnings from continuing operations, including the potential issuance of common shares upon the exercise, conversion or vesting of outstanding stock options and unvested restricted shares, as calculated under the treasury stock method, as well as shares associated with the Company’s convertible debt securities, which matured and were converted in 2014.

Computation of earnings per share, methodology

The 2011 Convertible Notes had an optional cash settlement feature, which allowed the Company to settle the principal amount in cash. Until their maturity in 2014, dilutive shares associated with the 2011 Convertible Notes were derived from the premium value of the notes in excess of their principal amounts, as calculated using the treasury stock method. These shares were referred to as “premium shares.”