Impairment, Restructuring and Other Exit Costs - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Restructuring [Line Items]
Tota expected Cost		$ 250,000
Total severance cost	$ 3,000	100,000		$ 35,000
Operating Lease, Impairment Loss	6,000			6,000
Impairment charges	35,000	60,000		57,000
Cumulative translation adjustments		80,000
Restructuring and Related Cost, Other		$ 10,000
Impairment, Restructuring, And Other Costs	44,000			98,000
Restructuring charges	333,988		$ 0	388,027	$ 0
Current liabilities held for sale ($80,452 and $79,872 related to VIEs)	414,343			414,343		$ 380,815
Fair value of the other impaired assets	25,000			25,000
Investments	607,000			607,000		886,000
Customer Relationships
Restructuring [Line Items]
Impairment, Restructuring, And Other Costs				34,000
Other Assets	32,000			$ 32,000
COOEC Fluor Heavy Industries Co., Ltd.
Restructuring [Line Items]
Ownership interest in joint venture (as a percent)				49.00%
SACYR
Restructuring [Line Items]
Impairment loss				$ 31,000
Investments	6,000			$ 6,000
Offshore Oil Engineering Co., Ltd. | COOEC Fluor Heavy Industries Co., Ltd.
Restructuring [Line Items]
Ownership interest in joint venture (as a percent)				51.00%
CFHI
Restructuring [Line Items]
Impairment loss				$ 225,000
Investments	$ 112,000			$ 112,000		$ 376,000