Merger of FMC Technologies and Technip (Goodwill Allocation) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Jan. 16, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 8,929.8		$ 3,718.3	$ 3,786.5	$ 4,114.2
Subsea
Business Acquisition [Line Items]
Goodwill	5,470.4		2,931.1	2,977.4	3,232.0
Onshore/Offshore
Business Acquisition [Line Items]
Goodwill	2,461.6		787.2	809.1	882.2
Surface Technologies
Business Acquisition [Line Items]
Goodwill	$ 997.8		$ 0.0	$ 0.0	$ 0.0
FMCTI Merger
Business Acquisition [Line Items]
Goodwill		$ 5,161.0
FMCTI Merger | Subsea
Business Acquisition [Line Items]
Goodwill		2,527.7
FMCTI Merger | Onshore/Offshore
Business Acquisition [Line Items]
Goodwill		1,635.5
FMCTI Merger | Surface Technologies
Business Acquisition [Line Items]
Goodwill		$ 997.8