GOODWILL AND INTANGIBLE ASSETS - Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Beginning balance	$ 3,128.5	$ 3,128.5
Impairments		(3,083.4)	$ (1,988.7)
Translation		(45.1)
Ending balance			3,128.5
Subsea
Goodwill [Roll Forward]
Beginning balance	2,792.8	2,792.8
Impairments	(2,747.5)	(2,747.5)
Translation		(45.3)
Ending balance			2,792.8
Surface Technologies
Goodwill [Roll Forward]
Beginning balance	335.7	335.7
Impairments	$ (335.9)	(335.9)
Translation		$ 0.2
Ending balance			$ 335.7

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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