Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Trade receivables	$ 113.5	$ 76.8
Trade payables	61.2	51.1
Note receivables	40.3	65.2
Revenue	274.2	379.6	$ 293.3
Expenses	149.7	142.4	154.7
TP JGC Coral France SNC \| Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	38.1	40.1
Revenue	44.2	110.4	118.2
Expenses		5.0
Jumbo Shipping [Member] \| Director
Related Party Transaction [Line Items]
Expenses	16.0	4.5
TTSJV W.L.L. [Member] \| Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	14.9	22.4
Revenue	47.2	127.9	0.0
Techdof Brasil AS \| Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	8.0	4.3
Revenue	11.2	8.3	7.0
Technip Odebrecht PLSV CV [Member] \| Equity Method Investee
Related Party Transaction [Line Items]
Revenue		11.9	7.2
Anadarko Petroleum Company [Member] \| Director
Related Party Transaction [Line Items]
Revenue		67.1	124.8
Dofcon Navegacao Ltda \| Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	4.2	0.0
Trade payables	1.5	2.1
Revenue	3.4	8.4	2.9
Expenses	24.0	1.8	0.0
Chiyoda
Related Party Transaction [Line Items]
Trade payables	14.2	24.8
Expenses	1.4	25.1	53.0
JGC Corporation
Related Party Transaction [Line Items]
Trade payables	1.9	15.1
Revenue		6.7	0.0
Expenses	0.4	20.8	81.2
Serimax Holdings SAS [Member] \| Equity Method Investee
Related Party Transaction [Line Items]
Expenses	0.4	17.7	0.1
IFP Energies nouvelles \| Director
Related Party Transaction [Line Items]
Trade payables		2.4
Arkema S.A. \| Director
Related Party Transaction [Line Items]
Expenses	5.3	18.9	2.6
Magma Global Limited \| Equity Method Investee
Related Party Transaction [Line Items]
Expenses	14.0	7.3	3.0
Others \| Other Affiliates
Related Party Transaction [Line Items]
Trade receivables	8.4	6.9
Trade payables	5.7	6.7
Revenue	27.2	29.7	33.2
Expenses	24.6	41.3	14.8
Storengy \| Director
Related Party Transaction [Line Items]
Trade receivables	6.1	3.1
Revenue	10.7	8.8
Equinor ASA \| Director
Related Party Transaction [Line Items]
Trade receivables	24.1	0.0
Revenue	81.1	0.0	0.0
Novarctic SNC \| Equity Method Investee
Related Party Transaction [Line Items]
Trade receivables	9.7	0.0
Revenue	10.7	0.4	0.0
Nipigas
Related Party Transaction [Line Items]
Trade payables	14.2
Expenses	36.8	0.0	0.0
Saipem
Related Party Transaction [Line Items]
Trade payables	23.7
Expenses	26.8	0.0	0.0
Equinor Brasil \| Director
Related Party Transaction [Line Items]
Revenue	$ 38.5	$ 0.0	$ 0.0

Amount for accounts payable to related parties.

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