| Cover | Dec. 10, 2020 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 10, 2020 |
| Entity File Number | 001-16129 |
| Entity Registrant Name | FLUOR CORPORATION |
| Entity Central Index Key | 0001124198 |
| Entity Tax Identification Number | 33-0927079 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 6700 Las Colinas Blvd. |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $.01 par value per share |
| Trading Symbol | FLR |
| Security Exchange Name | NYSE |
| Rights [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Preferred Stock Purchase Rights |
| Trading Symbol | FLR |
| Security Exchange Name | NYSE |
