Major Accounting Policies - Significant Items Reclassified Out of AOCI (Details 6) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reclassifications out of accumulated other comprehensive income (loss)
Gain related to a partial sale of a subsidiary									$ 68,162
Total cost of revenue	$ (4,118,300)	$ (4,133,800)	$ (4,516,100)	$ (4,251,200)	$ (5,093,800)	$ (5,060,000)	$ (4,906,400)	$ (5,072,300)	(17,019,352)	$ (20,132,544)	$ (25,986,382)
Interest expense									(44,770)	(29,681)	(26,887)
Corporate general and administrative expense									(168,329)	(182,711)	(175,148)
Income tax expense									(245,888)	(352,815)	(354,573)
NET EARNINGS	(33,000)	181,700	160,700	165,600	229,300	114,900	110,000	193,300	475,006	647,543	823,026
Net earnings attributable to noncontrolling interests									62,494	136,634	155,315
NET EARNINGS ATTRIBUTABLE TO FLUOR CORPORATION	$ (51,400)	$ 171,300	$ 148,500	$ 144,100	$ 214,500	$ 69,500	$ 77,800	$ 149,100	412,512	510,909	667,711
Foreign Currency Translation | Reclassified out of AOCI
Reclassifications out of accumulated other comprehensive income (loss)
Gain related to a partial sale of a subsidiary									(9,932)
Income tax expense									3,724
NET EARNINGS									(6,208)
Ownership Share of Equity Method Investees' Other Comprehensive Income (Loss) | Reclassified out of AOCI
Reclassifications out of accumulated other comprehensive income (loss)
Total cost of revenue									(1,487)	(15,662)
Income tax expense										5,866
NET EARNINGS									(1,487)	(9,796)
Defined Benefit Pension and Postretirement Plans
Reclassifications out of accumulated other comprehensive income (loss)
Adjustments									(268,795)	(12,922)	(12,931)
Income tax benefit									100,798	4,846	4,849
Net of tax									(167,997)	(8,076)	(8,082)
Unrealized Gain on Derivative Contracts, including noncontrolling interests | Reclassified out of AOCI
Reclassifications out of accumulated other comprehensive income (loss)
Income tax expense									1,933	541	2,322
NET EARNINGS									(3,235)	(882)	(3,858)
Unrealized Gain on Derivative Contracts, including noncontrolling interests | Reclassified out of AOCI | Commodity contracts and foreign currency contracts
Reclassifications out of accumulated other comprehensive income (loss)
Total cost of revenue									(3,490)	255	(4,502)
Unrealized Gain on Derivative Contracts, including noncontrolling interests | Reclassified out of AOCI | Interest rate contracts
Reclassifications out of accumulated other comprehensive income (loss)
Interest expense									(1,678)	(1,678)	(1,678)
Unrealized Gain (Loss) on Derivative Contracts Attributable Noncontrolling Interests | Reclassified out of AOCI
Reclassifications out of accumulated other comprehensive income (loss)
Net earnings attributable to noncontrolling interests									(276)	(43)	(4)
Unrealized Gain (Loss) on Derivative Contracts | Reclassified out of AOCI
Reclassifications out of accumulated other comprehensive income (loss)
NET EARNINGS ATTRIBUTABLE TO FLUOR CORPORATION									(2,959)	(839)	(3,854)
Unrealized Gain (Loss) on Available-for-Sale Securities | Reclassified out of AOCI
Reclassifications out of accumulated other comprehensive income (loss)
Corporate general and administrative expense									152	140	202
Income tax expense									(57)	(52)	(76)
NET EARNINGS									$ 95	$ 88	$ 126