Quarterly report pursuant to Section 13 or 15(d)

Cover Page

Cover Page - shares
3 Months Ended
Mar. 31, 2021
May 04, 2021
Document And Entity Information [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2021  
Document Transition Report false  
Entity File Number 001-13831  
Entity Registrant Name Quanta Services, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 74-2851603  
Entity Address, Address Line One 2800 Post Oak Boulevard, Suite 2600  
Entity Address, City or Town Houston  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 77056  
City Area Code 713  
Local Phone Number 629-7600  
Title of 12(b) Security Common Stock, $0.00001 par value  
Trading Symbol PWR  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   139,346,092
Document Fiscal Period Focus Q1  
Amendment Flag false  
Document Fiscal Year Focus 2021  
Current Fiscal Year End Date --12-31  
Entity Central Index Key 0001050915