RELATED PARTY TRANSACTIONS - Trade Receivables (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Total accounts receivable	$ 174.1	$ 38.0
Technip Energies | Equity Method Investee
Related Party Transaction [Line Items]
Total accounts receivable	130.5	0.0
Equinor ASA | Director
Related Party Transaction [Line Items]
Total accounts receivable	32.1	24.1
Dofcon Navegacao | Equity Method Investee
Related Party Transaction [Line Items]
Total accounts receivable	2.9	4.2
Techdof Brasil AS | Equity Method Investee
Related Party Transaction [Line Items]
Total accounts receivable	6.5	8.0
Others | Other Affiliates
Related Party Transaction [Line Items]
Total accounts receivable	$ 2.1	$ 1.7