| Document and Entity Information | Oct. 31, 2019 |
| Cover [Abstract] | |
| Entity Registrant Name | MASTEC INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000015615 |
| Document Type | 8-K |
| Document Period End Date | Oct. 31, 2019 |
| Entity Incorporation State Country Code | FL |
| Entity File Number | 001-08106 |
| Entity Tax Identification Number | 65-0829355 |
| Entity Address, Address Line One | 800 S. Douglas Road |
| Entity Address, Address Line Two | 12th Floor |
| Entity Address, City or Town | Coral Gables |
| Entity Address, State or Province | FL |
| Entity Address, Postal Zip Code | 33134 |
| City Area Code | (305) |
| Local Phone Number | 599-1800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.10 Par Value |
| Trading Symbol | MTZ |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
