Restructuring and Impairment Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restructuring and Impairment
Impairment, restructuring and other expense	$ (12.3)	$ 63.8	$ (2.6)	$ 99.5
Subsea
Restructuring and Impairment
Impairment, restructuring and other expense	6.0	20.0	12.7	20.3
Onshore/Offshore
Restructuring and Impairment
Impairment, restructuring and other expense	(27.7)	29.2	(28.0)	64.6
Surface Technologies
Restructuring and Impairment
Impairment, restructuring and other expense	2.8		4.2
Corporate and Other
Restructuring and Impairment
Impairment, restructuring and other expense	$ 6.6	$ 14.6	$ 8.5	$ 14.6