Stock-Based Compensation - Grant Date Fair Value for Awards of Performance Units Inputs (Details) - PSUs - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Mar. 09, 2023	Mar. 02, 2022	Mar. 25, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Valuation date price based on March 9, 2023, March 2, 2022 and March 25, 2021 closing stock prices of Quanta common stock (in usd per share)				$ 160.55	$ 110.24	$ 83.48
Expected volatility	35.00%	39.00%	36.00%
Risk-free interest rate	4.62%	1.64%	0.26%
Term in years	2 years 9 months 21 days	2 years 9 months 29 days	2 years 9 months 7 days