Related Party Transactions	9 Months Ended
Related Party Transactions	Sep. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions MasTec purchases, rents and leases equipment and purchases various types of supplies and services used in its business, including ancillary construction services, project-related site restoration and marketing and business development activities from a number of different vendors on a non-exclusive basis, and, from time to time, rents equipment to, sells certain supplies, or performs construction services on behalf of, entities in which members of subsidiary management have ownership or commercial interests. For the three month periods ended September 30, 2021 and 2020, such payments to related party entities totaled approximately $20.7 million and $23.8 million, respectively, and for the nine month periods ended September 30, 2021 and 2020, totaled approximately $71.8 million and $65.3 million, respectively. Payables associated with such arrangements totaled approximately $0.6 million and $8.9 million as of September 30, 2021 and December 31, 2020, respectively. Revenue from such related party arrangements totaled approximately $0.8 million and $0.9 million for the three month periods ended September 30, 2021 and 2020, respectively, and totaled approximately $2.9 million and $3.2 million for the nine month periods ended September 30, 2021 and 2020, respectively. Related amounts receivable, net, totaled approximately $0.3 million and $0.5 million as of September 30, 2021 and December 31, 2020, respectively. The Company rents and leases equipment and purchases certain supplies and servicing from CCI. Juan Carlos Mas, who is the brother of Jorge Mas, Chairman of MasTec’s Board of Directors and José R. Mas, MasTec’s Chief Executive Officer, serves as the chairman of CCI, and a member of management of a MasTec subsidiary and an entity that is owned by the Mas family are minority owners. MasTec paid CCI $8.0 million and $1.8 million, net of rebates, respectively, for the three month periods ended September 30, 2021 and 2020, and paid approximately $18.6 million and $3.2 million, respectively, for the nine month periods ended September 30, 2021 and 2020 related to this activity. Amounts payable to CCI, net of rebates receivable, totaled approximately $3.4 million and $4.2 million as of September 30, 2021 and December 31, 2020, respectively. MasTec has a subcontracting arrangement with an entity for the performance of construction services, the minority owners of which include an entity controlled by Jorge Mas and José R. Mas, along with two members of management of a MasTec subsidiary. For the three month period ended September 30, 2021, MasTec incurred subcontracting expenses of approximately $41.1 million under these arrangements, and no subcontracting expenses were incurred for the three month period ended September 30, 2020. For the nine month period ended September 30, 2021, MasTec incurred subcontracting expenses under these arrangements of approximately $86.9 million, and for the nine month period ended September 30, 2020, incurred approximately $0.6 million, net. As of September 30, 2021 and December 31, 2020, related amounts payable totaled approximately $7.1 million and $1.4 million, respectively. MasTec has a leasing arrangement for an aircraft that is owned by an entity that Jorge Mas owns. For both the three month periods ended September 30, 2021 and 2020, MasTec paid approximately $0.6 million related to this leasing arrangement, and paid approximately $1.9 million for both the nine month periods ended September 30, 2021 and 2020. MasTec performs construction services on behalf of a professional Miami soccer franchise (the “Franchise”) in which Jorge Mas and José R. Mas are minority owners. Services provided by MasTec include the construction of a soccer facility and stadium as well as wireless infrastructure services. For both the three and nine month periods ended September 30, 2021, charges under these arrangements were de minimis, and for the three and nine month periods ended September 30, 2020, MasTec charged approximately $0.7 million and $6.2 million, respectively. Related amounts outstanding as of both September 30, 2021 and December 31, 2020 were de minimis. Payments for other expenses related to the Franchise for the nine month periods ended September 30, 2021 and 2020 totaled approximately $0.3 million and $0.2 million, respectively, for which there were no amounts outstanding as of either September 30, 2021 or December 31, 2020. MasTec leases employees and provides satellite communication services to a customer in which Jorge Mas and José R. Mas own a majority interest. Charges to this customer under these arrangements totaled approximately $0.3 million for both the three month periods ended September 30, 2021 and 2020, and for the nine month periods ended September 30, 2021 and 2020, totaled approximately $0.9 million and $1.0 million, respectively. As of September 30, 2021 and December 31, 2020, related amounts receivable totaled approximately $0.8 million and $0.9 million, respectively. Amounts outstanding, net, for advances made by the Company on behalf of a construction management firm specializing in steel building systems that was acquired by MasTec, of which Juan Carlos Mas was a minority owner at the time of acquisition, were de minimis as of both September 30, 2021 and December 31, 2020. Outstanding amounts are expected to be settled under customary terms associated with the related purchase agreement. During the third quarter of 2021, certain provisions relating to contingent consideration within the purchase agreement were clarified, for which the net impact is expected to be insignificant. For the three month period ended September 30, 2021, the Company paid $0.8 million of contingent consideration related to this agreement. The Company, through a second quarter 2020 acquisition, has a 25% interest in an entity, under which the acquired business and the 25%-owned entity have a subcontracting arrangement. The Company’s interest in this entity, for which post-acquisition operating activity is de minimis, is accounted for as an equity method investment. As of September 30, 2021 and December 31, 2020, the Company’s net investment in this entity was a liability of approximately $1.6 million and $2.0 million, respectively, which net amount includes approximately $2.3 million and $1.9 million, respectively, of accounts receivable, net, less deferred revenue, related to the subcontracting arrangement. Additionally, the Company has certain arrangements with an entity in which members of management have an ownership interest, including a fee arrangement in conjunction with a $15.0 million letter of credit issued by the Company on behalf of this entity. For the three and nine month periods ended September 30, 2021, approximately $0.2 million and $0.6 million, respectively, of income was recognized in connection with these arrangements, and for both the three and nine month periods ended September 30, 2020, approximately $0.6 million of income was recognized. As of September 30, 2021 and December 31, 2020, related amounts receivable totaled $0.2 million and $0.4 million, respectively. Non-controlling interests in entities consolidated by the Company represent ownership interests held by members of management of certain of the Company’s subsidiaries, primarily in the Company’s Oil and Gas segment. In June 2021, the Company acquired an additional 15% of the non-controlling interests in one of these entities from two members of subsidiary management for $6.8 million in cash. Split Dollar Agreements MasTec has split dollar life insurance agreements with trusts, for one of which Jorge Mas is a trustee, and for one of which José R. Mas is a trustee. For both the three month periods ended September 30, 2021 and 2020, the Company paid $0.6 million in connection with the agreements for Jorge Mas, and no payments were made for José R. Mas. For both the nine month periods ended September 30, 2021 and 2020, the Company paid $1.1 million in connection with the agreements for Jorge Mas, and paid $0.7 million for José R. Mas. As of September 30, 2021 and December 31, 2020, life insurance assets associated with these agreements totaled approximately $24.0 million and $22.2 million, respectively.