Major Accounting Policies - Tax Effects of Components of Other Comprehensive Income (Loss) (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other comprehensive income (loss), Before-Tax Amount:
Total other comprehensive income (loss), Before-Tax	$ 78,062	$ (301,963)	$ (69,411)
Less: Other comprehensive loss attributable to noncontrolling interests, Before-Tax	(1,267)	(7,309)	(772)
Other comprehensive income (loss) attributable to Fluor Corporation, Before-Tax	79,329	(294,654)	(68,639)
Other comprehensive income (loss), Tax (Expense) Benefit:
Total other comprehensive income (loss), Tax (Expense) Benefit	(27,892)	108,643	28,288
Other comprehensive income (loss) attributable to Fluor Corporation, Tax (Expense) Benefit	(27,892)	108,643	28,288
Other comprehensive income (loss), Net-of-Tax Amount:
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	50,170	(193,320)	(41,123)
Less: Other comprehensive loss attributable to noncontrolling interests, Net-of-Tax	(1,267)	(7,309)	(772)
Other comprehensive income (loss) attributable to Fluor Corporation, Net-of-Tax	51,437	(186,011)	(40,351)
Foreign Currency Translation, including noncontrolling interests
Other comprehensive income (loss), Before-Tax Amount:
Total other comprehensive income (loss), Before-Tax	(166,487)	(197,361)	(74,538)
Other comprehensive income (loss), Tax (Expense) Benefit:
Total other comprehensive income (loss), Tax (Expense) Benefit	61,892	71,552	27,637
Other comprehensive income (loss), Net-of-Tax Amount:
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(104,595)	(125,809)	(46,901)
Ownership Share of Equity Method Investees' Other Comprehensive Income (Loss)
Other comprehensive income (loss), Before-Tax Amount:
Total other comprehensive income (loss), Before-Tax	(12,226)	5,892	13,117
Other comprehensive income (loss), Tax (Expense) Benefit:
Total other comprehensive income (loss), Tax (Expense) Benefit	4,713	(4,054)	(2,372)
Other comprehensive income (loss), Net-of-Tax Amount:
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(7,513)	1,838	10,745
Defined Benefit Pension and Postretirement Plan adjustments, including noncontrolling interests
Other comprehensive income (loss), Before-Tax Amount:
Total other comprehensive income (loss), Before-Tax	257,414	(106,957)	(8,917)
Other comprehensive income (loss), Tax (Expense) Benefit:
Total other comprehensive income (loss), Tax (Expense) Benefit	(94,799)	40,109	3,344
Other comprehensive income (loss), Net-of-Tax Amount:
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	162,615	(66,848)	(5,573)
Unrealized Gain on Derivative Contracts, including noncontrolling interests
Other comprehensive income (loss), Before-Tax Amount:
Total other comprehensive income (loss), Before-Tax	(302)	(2,837)	2,171
Other comprehensive income (loss), Tax (Expense) Benefit:
Total other comprehensive income (loss), Tax (Expense) Benefit	176	773	(787)
Other comprehensive income (loss), Net-of-Tax Amount:
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	(126)	(2,064)	1,384
Unrealized Gain (Loss) on Available-for-Sale Securities, including noncontrolling interests
Other comprehensive income (loss), Before-Tax Amount:
Total other comprehensive income (loss), Before-Tax	(337)	(700)	(1,244)
Other comprehensive income (loss), Tax (Expense) Benefit:
Total other comprehensive income (loss), Tax (Expense) Benefit	126	263	466
Other comprehensive income (loss), Net-of-Tax Amount:
TOTAL OTHER COMPREHENSIVE INCOME ( LOSS), NET OF TAX	$ (211)	$ (437)	$ (778)