Revenue - Disaggregation of Revenue, Geographical (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2019		Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Lease revenue		$ 52.6		$ 53.3		$ 115.2	$ 102.7
Total revenue		3,434.2		2,960.9		6,347.2	6,086.1
Services
Disaggregation of Revenue [Line Items]
Revenue		2,548.8		2,066.0		4,599.9	4,340.0
Products
Disaggregation of Revenue [Line Items]
Revenue		832.8		841.6		1,632.1	1,643.4
Subsea
Disaggregation of Revenue [Line Items]
Revenue		1,488.5	[1]	1,184.0		2,645.9	2,338.4	[1]
Lease revenue	[2]	20.2		33.4		48.1	59.2
Subsea | Services
Disaggregation of Revenue [Line Items]
Revenue		970.2		656.5	[1]	1,615.8	1,309.4	[1]
Subsea | Products
Disaggregation of Revenue [Line Items]
Revenue		518.3		527.5	[1]	1,030.1	1,029.0	[1]
Subsea | Europe, Russia, Central Asia
Disaggregation of Revenue [Line Items]
Revenue		459.6		409.4		859.2	714.9
Subsea | America
Disaggregation of Revenue [Line Items]
Revenue		341.8		331.3		718.9	781.9
Subsea | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue		177.7		137.9		277.4	249.9
Subsea | Africa
Disaggregation of Revenue [Line Items]
Revenue		373.8		261.6		519.6	541.4
Subsea | Middle East
Disaggregation of Revenue [Line Items]
Revenue		135.6		43.8		270.8	50.3
Onshore/Offshore
Disaggregation of Revenue [Line Items]
Revenue		1,505.0		1,342.4		2,840.1	2,915.8
Lease revenue	[2]	0.0		0.0		0.0	0.0
Onshore/Offshore | Services
Disaggregation of Revenue [Line Items]
Revenue		1,505.0		1,342.4		2,840.1	2,915.8
Onshore/Offshore | Products
Disaggregation of Revenue [Line Items]
Revenue		0.0		0.0		0.0	0.0
Onshore/Offshore | Europe, Russia, Central Asia
Disaggregation of Revenue [Line Items]
Revenue		651.2		705.5		1,292.8	1,706.4
Onshore/Offshore | America
Disaggregation of Revenue [Line Items]
Revenue		196.9		90.9		357.3	163.6
Onshore/Offshore | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue		275.5		310.6		577.4	605.9
Onshore/Offshore | Africa
Disaggregation of Revenue [Line Items]
Revenue		111.1		76.9		171.5	147.5
Onshore/Offshore | Middle East
Disaggregation of Revenue [Line Items]
Revenue		270.3		158.5		441.1	292.4
Surface Technologies
Disaggregation of Revenue [Line Items]
Revenue		388.1		381.2		746.0	729.2
Lease revenue	[2]	32.4		19.9		67.1	43.5
Surface Technologies | Services
Disaggregation of Revenue [Line Items]
Revenue		73.6		67.1		144.0	114.8
Surface Technologies | Products
Disaggregation of Revenue [Line Items]
Revenue		314.5		314.1		602.0	614.4
Surface Technologies | Europe, Russia, Central Asia
Disaggregation of Revenue [Line Items]
Revenue		60.0		58.3		115.8	106.5
Surface Technologies | America
Disaggregation of Revenue [Line Items]
Revenue		199.9		237.5		393.1	445.0
Surface Technologies | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue		44.1		29.7		89.1	51.8
Surface Technologies | Africa
Disaggregation of Revenue [Line Items]
Revenue		14.9		11.4		26.2	27.1
Surface Technologies | Middle East
Disaggregation of Revenue [Line Items]
Revenue		69.2		44.3		121.8	98.8
Restatement Adjustment | Services
Disaggregation of Revenue [Line Items]
Revenue				(177.9)			(331.3)
Restatement Adjustment | Products
Disaggregation of Revenue [Line Items]
Revenue				177.9			331.3
Operating Segments | Subsea
Disaggregation of Revenue [Line Items]
Total revenue		1,508.7		1,217.4		2,694.0	2,397.6
Operating Segments | Onshore/Offshore
Disaggregation of Revenue [Line Items]
Total revenue		1,505.0		1,342.4		2,840.1	2,915.8
Operating Segments | Surface Technologies
Disaggregation of Revenue [Line Items]
Total revenue		$ 420.5		$ 401.1		$ 813.1	$ 772.7

[1] We revised the condensed consolidated statement of operations to correct the classification of service revenue and product revenue in the amount of $177.9 million and $331.3 million for three and six months ended June 30, 2018, respectively. See Note 1 to our condensed consolidated financial statements of this Quarterly Report for additional disclosure related to the revision.

[2] Represents revenue not subject to ASC Topic 606. See Note 4 to our condensed consolidated financial statements of this Quarterly Report for additional disclosure related to lease revenue.