Equity Method Investments (Income (Loss) From Equity Affiliates by Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Income from equity affiliates	$ 55.6	$ 117.7	$ 51.0
Subsea
Schedule of Equity Method Investments [Line Items]
Income from equity affiliates	55.3	35.0	21.2
Onshore/Offshore
Schedule of Equity Method Investments [Line Items]
Income from equity affiliates	0.3	82.7	29.8
Surface Technologies
Schedule of Equity Method Investments [Line Items]
Income from equity affiliates	$ 0.0	$ 0.0	$ 0.0
Technip Odebrecht PLSV CV
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Technip Odebrecht PLSV CV | Subsea
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Dofcon Brasil AS
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Dofcon Brasil AS | Subsea
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Serimax Holdings SAS
Schedule of Equity Method Investments [Line Items]
Ownership percentage	20.00%
Serimax Holdings SAS | Subsea
Schedule of Equity Method Investments [Line Items]
Ownership percentage	20.00%
FSTP Brasil Ltda
Schedule of Equity Method Investments [Line Items]
Ownership percentage	25.00%
FSTP Brasil Ltda | Subsea
Schedule of Equity Method Investments [Line Items]
Ownership percentage	25.00%
Yamgaz | Onshore/Offshore
Schedule of Equity Method Investments [Line Items]
Ownership percentage	50.00%