Earnings Per Share (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Line Items]
Computation of earnings per share, methodology	Basic earnings per share is computed by dividing earnings 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 earnings 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. The potential issuance of common shares upon the exercise, conversion or vesting of outstanding stock options and unvested restricted share awards, as calculated under the treasury stock method, as well as shares associated with the Company’s outstanding convertible debt securities, may be dilutive.
Anti-dilutive common stock equivalents, shares	61,226	0
Convertible Debt [Member] | 2011 Convertible Notes [Member]
Earnings Per Share [Line Items]
Computation of earnings per share, methodology	Due to the optional cash settlement feature of the 2011 Convertible Notes and the Company's intent to settle the principal amount of such notes in cash, the conversion shares underlying the outstanding principal amount of the 2011 Convertible Notes, totaling approximately 13.0 million shares, are not required to be included in the Company's diluted share count. If, however, the average price per share of the Company's common stock exceeds the respective conversion prices of the 2011 Convertible Notes, then the resulting premium is translated into shares, referred to as “premium shares,” the number of which is required to be included in the Company's diluted share count. The number of premium shares included in our diluted share count varies with fluctuations in our share price. Higher share prices result in a greater number of premium shares. The Company’s weighted average share price for the three month periods ended March 31, 2014 and 2013 exceeded the conversion prices of the 2011 Convertible Notes, and as a result, dilutive premium shares have been included in the Company's share count for the corresponding periods.
Number of conversion shares, principal amount	13,000,000
Convertible Debt [Member] | 2009 Convertible Notes [Member]
Earnings Per Share [Line Items]
Computation of earnings per share, methodology	Dilutive shares associated with the 2009 Convertible Notes are attributable to the underlying principal amounts. The number of common shares issuable upon conversion of the Company’s 2009 Convertible Notes is reflected in the calculation of weighted average diluted earnings per share for the corresponding periods by application of the “if-converted” method to the extent its effect on the computation of earnings per share from continuing operations is dilutive. Under the “if-converted” method, net income from continuing operations is adjusted to add back the after-tax amount of interest recognized for the period associated with the convertible notes, and correspondingly, the convertible notes are assumed to have been converted with the resulting common shares added to the number of weighted average shares outstanding.
Convertible Debt [Member] | 2011 4.0% Notes [Member]
Earnings Per Share [Line Items]
Number of conversion shares, principal amount	6,683,000	6,683,000
Convertible Debt [Member] | 2011 4.25% Notes [Member]
Earnings Per Share [Line Items]
Number of conversion shares, principal amount	6,268,000	6,268,000
Unsecured Debt [Member] | Convertible Debt [Member] | Total Convertible Debt [Member]
Earnings Per Share [Line Items]
Principal amount	$ 215.0
Unsecured Debt [Member] | Convertible Debt [Member] | 2011 Convertible Notes [Member]
Earnings Per Share [Line Items]
Principal amount	202.3
Unsecured Debt [Member] | Convertible Debt [Member] | 2009 Convertible Notes [Member]
Earnings Per Share [Line Items]
Principal amount	12.6
Unsecured Debt [Member] | Convertible Debt [Member] | 2011 4.0% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	105.3
Debt instrument, interest rate	4.00%
Conversion price per share	$ 15.76
Unsecured Debt [Member] | Convertible Debt [Member] | 2011 4.25% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	$ 97.0
Debt instrument, interest rate	4.25%
Conversion price per share	$ 15.48