Cover - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	1-16129
Entity Registrant Name	FLUOR CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0927079
Entity Address, Address Line One	6700 Las Colinas Boulevard
Entity Address, City or Town	Irving,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75039
City Area Code	469
Local Phone Number	398-7000
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		141,411,916
Entity Central Index Key	0001124198
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
NEW YORK STOCK EXCHANGE | Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, $.01 par value per share
Trading Symbol	FLR
Security Exchange Name	NYSE
NEW YORK STOCK EXCHANGE | 1.750% Senior Notes due 2023
Document Information [Line Items]
Title of 12(b) Security	1.750% Senior Notes due 2023
Trading Symbol	FLR 23
Security Exchange Name	NYSE