Restructuring and Impairment Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring and Impairment
Impairment, restructuring and other expense	$ 59.4	$ 10.2	$ 56.8	$ 109.7
Subsea
Restructuring and Impairment
Impairment, restructuring and other expense	22.8	3.7	35.5	24.0
Onshore/Offshore
Restructuring and Impairment
Impairment, restructuring and other expense	28.9	5.2	0.9	69.8
Surface Technologies
Restructuring and Impairment
Impairment, restructuring and other expense	7.8		12.0
Corporate and Other
Restructuring and Impairment
Impairment, restructuring and other expense	$ (0.1)	$ 1.3	$ 8.4	$ 15.9