FAIR VALUE MEASUREMENTS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash proceeds	$ 48.0
Redeemable Noncontrolling Interest	0.0	$ 0.0	$ 43.7
Derivative, Credit Risk Related Contingent Features, Existence and Nature		We currently have no credit-risk-related contingent features in our agreements with the financial institutions that would require us to post collateral for derivative positions in a liability position.
Debt, fair value	$ 2,165.6	$ 2,165.6	$ 2,199.2
Island Offshore Subsea AS \| Island Offshore Subsea AS
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Redeemable noncontrolling interest, acquired percent			51.00%

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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