Acquisitions (2014 Acquisitions) (Narrative) (Details) (USD $)	6 Months Ended						3 Months Ended	6 Months Ended		6 Months Ended	0 Months Ended	6 Months Ended		0 Months Ended	6 Months Ended		0 Months Ended	6 Months Ended	0 Months Ended	6 Months Ended	0 Months Ended	6 Months Ended	0 Months Ended	6 Months Ended
	Jun. 30, 2014 Earn-Out Arrangements [Member]	Jun. 30, 2013 Earn-Out Arrangements [Member]	Jun. 30, 2014 Performance Standby [Member]	Dec. 31, 2013 Performance Standby [Member]	Jun. 30, 2014 Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] Performance Standby [Member]	Jun. 30, 2014 Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] Financial Guarantee [Member]	Jun. 30, 2014 Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] Infrastructure Construction Services [Member] Related Customer [Member]	Jun. 30, 2014 Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] Infrastructure Construction Services [Member] Related Customer [Member]	Jun. 30, 2014 Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] Financing Arrangements [Member]	Jun. 30, 2014 Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] Equity Method Investments [Member]	Jun. 01, 2014 Pacer [Member]	Jun. 30, 2014 Pacer [Member]	Jun. 01, 2014 Pacer [Member]	Jun. 01, 2014 Pacer [Member] Earn-Out Arrangements [Member]	Jun. 30, 2014 Pacer [Member] Earn-Out Arrangements [Member]	Jun. 01, 2014 Pacer [Member] Earn-Out Arrangements [Member]	Apr. 01, 2014 April 2014 Acquisitions [Member]	Jun. 30, 2014 April 2014 Acquisitions [Member]	Apr. 01, 2014 April 2014 Acquisitions [Member] Earn-Out Arrangements [Member]	Jun. 30, 2014 April 2014 Acquisitions [Member] Earn-Out Arrangements [Member]	Jan. 01, 2014 January 2014 Acquisitions [Member]	Jun. 30, 2014 January 2014 Acquisitions [Member]	Jan. 01, 2014 January 2014 Acquisitions [Member] Earn-Out Arrangements [Member]	Jun. 30, 2014 January 2014 Acquisitions [Member] Earn-Out Arrangements [Member]
Business Acquisition [Line Items]
Business combinations, effective date												Jun. 01, 2014
Business combinations, percentage of voting interests acquired												100.00%						100.00%				100.00%
Business combinations, name of acquired entity												Pacer Construction Holdings Corporation and its affiliated operating companies (collectively, "Pacer")
Business combinations, description of acquired entity												Pacer is a western Canadian civil construction services company, headquartered in Calgary, Alberta, Canada.  Pacer’s services include infrastructure construction in support of the oil and gas production, processing, mining and transportation industries.						telecommunications services firm that specializes in the installation of in-home security systems				telecommunications services firm that specializes in the engineering, installation, furnishing and integration of telecommunications equipment
Business combinations, goodwill recognized, description												Goodwill arising from the acquisition represents the estimated value of Pacer's geographic presence in key high growth Canadian markets, its assembled workforce, its management team's industry-specific project management expertise and synergies expected to be achieved from the combined operations of Pacer and MasTec.
Business combinations, goodwill, expected tax deductible amount													$ 0
Equity method investments, number of										2
Revenue from related parties							1,000,000	1,000,000
Receivables, related parties							8,100,000	8,100,000
Due from related parties									12,100,000
Due from related parties, current									4,700,000
Due from related parties, long-term									7,400,000
Guarantees issued on behalf of related parties, amount			500,000,000	1,100,000,000	225,000,000	35,000,000
Business combinations, contingent consideration arrangements, basis for amount															The contingent earn-out obligation is equal to 25% of the excess, if any, of Pacer’s earnings from continuing operations before interest, taxes, depreciation and amortization (“EBITDA”) above certain thresholds for a five-year period, as set forth in the purchase agreement, and is payable annually in cash.
Business combinations, contingent consideration, percentage of excess EBITDA															25.00%
Business combinations, contingent consideration, earn-out period															5 years					5 years				5 years
Business combinations, contingent consideration, fair value measurements, significant assumptions															The fair value of the earn-out liability was estimated using an income approach and incorporates significant inputs not observable in the market. Key assumptions in the estimated valuation include the discount rate and probability-weighted EBITDA projections.
Business combinations, contingent consideration arrangements, range of outcomes, value, low																0
Business combinations, contingent consideration arrangements, range of outcomes, value, high																63,000,000
Business combinations, contingent consideration arrangements, range of outcomes, maximum unlimited															there is no maximum earn-out payment amount
Business combinations, payments in cash											126,500,000						18,100,000				23,800,000
Fair value of contingent consideration (earn-out liability)	$ 33,612,000	$ 26,721,000												$ 24,300,000					$ 600,000				$ 8,700,000