Related Party Transactions Schedule of Related Party Transactions (Tables) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Trade receivables	$ 81.0		$ 81.0		$ 76.8
Trade payables	19.4		19.4		51.1
Revenue	47.4	$ 92.3	113.8	$ 318.5
Expenses	13.2	29.8	42.9	107.6
TTSJV W.L.L. | Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	21.8		21.8		22.4
Revenue	9.7	27.9	38.3	107.4
TOP CV | Equity Method Investee
Related Party Transaction [Line Items]
Revenue		2.1		6.1
Serimax Holdings SAS | Equity Method Investee
Related Party Transaction [Line Items]
Expenses		0.0		17.7
Chiyoda
Related Party Transaction [Line Items]
Trade payables	15.0		15.0		24.8
Expenses	0.9	7.7	0.9	25.3
JGC Corporation
Related Party Transaction [Line Items]
Trade payables	2.5		2.5		15.1
Expenses	0.3	1.0	0.7	19.9
Arkema S.A. | Director
Related Party Transaction [Line Items]
Expenses	0.7	6.4	3.5	16.2
IFP Energies nouvelles | Director
Related Party Transaction [Line Items]
Trade payables					2.4
Dofcon Navegacao
Related Party Transaction [Line Items]
Expenses	5.2		17.0	0.4
Dofcon Navegacao | Equity Method Investee
Related Party Transaction [Line Items]
Trade payables	0.3		0.3		2.1
Revenue	0.8	1.4	1.4	7.1
TP JGC Coral France SNC | Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	34.0		34.0		40.1
Revenue	12.3	17.7	31.5	95.4
Anadarko Petroleum Company | Director
Related Party Transaction [Line Items]
Revenue		26.3		67.1
Others | Other Affiliates
Related Party Transaction [Line Items]
Trade receivables	15.4		15.4		14.3
Trade payables	1.6		1.6		6.7
Revenue	19.1	11.7	27.0	26.9
Expenses	6.1	14.7	20.8	28.1
Novarctic SNC | Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	9.8		9.8		$ 0.0
Techdof Brasil AS | Equity Method Investee
Related Party Transaction [Line Items]
Revenue	$ 2.0	$ 5.2	$ 6.4	$ 8.5