Business Segments (Other Business Segment Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Capital expenditures	$ 255.7	$ 312.9	$ 325.5
Depreciation and amortization	614.7	300.7	338.7
Research and development expense	212.9	105.4	95.5
Operating segments | Subsea
Segment Reporting Information [Line Items]
Capital expenditures	179.1	286.9	290.1
Depreciation and amortization	507.2	256.8	295.9
Research and development expense	169.2	75.4	67.1
Operating segments | Onshore/Offshore
Segment Reporting Information [Line Items]
Capital expenditures	16.2	26.0	35.4
Depreciation and amortization	41.1	43.9	42.8
Research and development expense	31.4	30.0	28.4
Operating segments | Surface Technologies
Segment Reporting Information [Line Items]
Capital expenditures	35.4	0.0	0.0
Depreciation and amortization	63.6	0.0	0.0
Research and development expense	12.3	0.0	0.0
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	25.0	0.0	0.0
Depreciation and amortization	2.8	0.0	0.0
Research and development expense	$ 0.0	$ 0.0	$ 0.0