Impairment, Restructuring and Other Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring and Impairment
Impairment, restructuring and other expenses	$ 9.7	$ 59.4	$ 32.6	$ 56.8
Subsea
Restructuring and Impairment
Impairment, restructuring and other expenses	5.0	22.8	19.1	35.5
Onshore/Offshore
Restructuring and Impairment
Impairment, restructuring and other expenses	(0.2)	28.9	(5.8)	0.9
Surface Technologies
Restructuring and Impairment
Impairment, restructuring and other expenses	1.3	7.8	8.0	12.0
Corporate and other
Restructuring and Impairment
Impairment, restructuring and other expenses	$ 3.6	$ (0.1)	$ 11.3	$ 8.4