Impairment, Restructuring and Other Expenses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restructuring and Impairment
Impairment, restructuring and other expenses	$ 11.4	$ (12.3)	$ 22.9	$ (2.6)
Subsea
Restructuring and Impairment
Impairment, restructuring and other expenses	11.0	6.0	14.1	12.7
Onshore/Offshore
Restructuring and Impairment
Impairment, restructuring and other expenses	(9.1)	(27.7)	(5.6)	(28.0)
Surface Technologies
Restructuring and Impairment
Impairment, restructuring and other expenses	4.3	2.8	6.7	4.2
Corporate and other
Restructuring and Impairment
Impairment, restructuring and other expenses	$ 5.2	$ 6.6	$ 7.7	$ 8.5