RELATED PARTY TRANSACTIONS - Trade Receivables (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Total accounts receivable	$ 168.2	$ 38.0
Technip Energies | Equity Method Investee
Related Party Transaction [Line Items]
Total accounts receivable	89.6	0.0
Equinor ASA | Director
Related Party Transaction [Line Items]
Total accounts receivable	48.6	24.1
Dofcon Navegacao | Equity Method Investee
Related Party Transaction [Line Items]
Total accounts receivable	18.8	4.2
Techdof Brasil AS | Equity Method Investee
Related Party Transaction [Line Items]
Total accounts receivable	9.8	8.0
Others | Other Affiliates
Related Party Transaction [Line Items]
Total accounts receivable	$ 1.4	$ 1.7