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Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Trade receivables	$ 61.7	$ 98.4
Trade payables	148.6	121.8
Note receivables	130.0	140.9
Revenue	293.3	238.1	$ 284.5
Expenses	154.7	141.4	105.5
TP JGC Coral France SNC \| Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	31.6	42.5
Revenue	118.2
Technip Odebrecht PLSV CV \| Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	10.9	13.8
Anadarko \| Board of Directors Chairman
Related Party Transaction [Line Items]
Trade receivables	4.9	22.3
Trade payables	0.7
Revenue	124.8	111.3
Dofcon Navegacao Ltda \| Equity Method Investee
Related Party Transaction [Line Items]
Trade payables	2.5	12.3
Chiyoda
Related Party Transaction [Line Items]
Trade payables	70.0	48.3
Expenses	53.0	44.1
JGC Corporation
Related Party Transaction [Line Items]
Trade payables	69.5	52.4
Expenses	81.2	46.8
IFP Energies nouvelles
Related Party Transaction [Line Items]
Trade payables	2.4
Expenses	4.4
Creoware OY
Related Party Transaction [Line Items]
Expenses	1.9	4.7
Arkema S.A.
Related Party Transaction [Line Items]
Expenses	2.6
Magma Global Limited \| Equity Method Investee
Related Party Transaction [Line Items]
Trade payables	0.6
Expenses	3.0
Heerema
Related Party Transaction [Line Items]
Expenses			71.3
Yamgaz \| Equity Method Investee
Related Party Transaction [Line Items]
Revenue			196.7
Others \| Other Affiliates
Related Party Transaction [Line Items]
Trade receivables	14.3	19.8
Trade payables	2.9	8.8
Revenue	50.3	126.8	87.8
Expenses	$ 8.6	$ 45.8	$ 34.2