Equity Method Investments (Percentage Owned and Carrying Value) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Investments in equity affiliates	$ 300.4	$ 394.5
Technip Odebrecht PLSV CV
Schedule of Equity Method Investments [Line Items]
Ownership percentage		50.00%
Investments in equity affiliates		$ 136.1
Dofcon Brasil AS
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%	50.00%
Investments in equity affiliates	$ 167.4	$ 126.2
Serimax Holdings SAS
Schedule of Equity Method Investments [Line Items]
Ownership percentage	20.00%	20.00%
Investments in equity affiliates	$ 21.5	$ 23.2
Magma Global Limited
Schedule of Equity Method Investments [Line Items]
Ownership percentage	25.00%	25.00%
Investments in equity affiliates	$ 50.2	$ 49.8
Other
Schedule of Equity Method Investments [Line Items]
Investments in equity affiliates	$ 61.3	$ 59.2