CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Income Statement [Abstract]
Revenue	$ 3,368	$ 4,094	$ 11,327	$ 12,055
Cost of revenue	(3,817)	(4,006)	(11,580)	(11,689)
Gross profit (loss)	(449)	88	(253)	366
G&A	(43)	(37)	(131)	(147)
Foreign currency gain (loss)	(4)	(2)	(47)	58
Operating profit (loss)	(496)	49	(431)	277
Interest expense	(11)	(11)	(31)	(35)
Interest income	24	48	79	149
Earnings (loss) before taxes	(483)	86	(383)	391
Income tax benefit (expense) (including $230 million tax benefit and $(454) million tax expense attributable to equity method earnings (loss) in 2025 Quarter and 2025 Period, respectively)	177	(61)	(536)	(172)
Net earnings (loss) before equity method earnings (loss)	(306)	25	(919)	219
Equity method earnings (loss)	(401)	0	2,418	0
Net earnings (loss)	(707)	25	1,499	219
Less: Net earnings (loss) attributable to NCI	(10)	(29)	(23)	(63)
Net earnings (loss) attributable to Fluor	$ (697)	$ 54	$ 1,522	$ 282
Basic EPS (in dollars per share)	$ (4.30)	$ 0.32	$ 9.21	$ 1.65
Diluted EPS (in dollars per share)	$ (4.30)	$ 0.31	$ 9.13	$ 1.63

Income (Loss) from Continuing Operations, Net of Tax, Before Equity Method Investments, Noncontrolling Interest

No definition available.

Name:	flr_IncomeLossFromContinuingOperationsNetOfTaxBeforeEquityMethodInvestmentsNoncontrollingInterest
Namespace Prefix:	flr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.