STOCKHOLDERS’ EQUITY - Reclassification out of accumulated other comprehensive income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	$ 7,824.2	$ 6,700.4	$ 6,403.5
Selling, general and administrative expense	(675.9)	(616.8)	(644.9)
Other Income (expense), net	(248.3)	5.4	46.6
Income before income taxes	206.6	68.9	198.1
Provision (benefit) for income taxes	154.7	105.4	111.1
Net income (loss) attributable to TechnipFMC plc	56.2	(107.2)	13.3
Gains on foreign currency translation | Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (expense), net	(7.0)	(3.2)	0.0
Defined pension and other post-retirement benefits | Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(5.5)	(12.9)	(22.0)
Provision (benefit) for income taxes	3.7	(3.8)	(4.0)
Net income (loss) attributable to TechnipFMC plc	(9.2)	(9.1)	(18.0)
Settlements and curtailments | Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (expense), net	0.0	(0.8)	(3.3)
Amortization of actuarial gain (loss) | Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (expense), net	(5.2)	(11.8)	(18.2)
Amortization of prior service credit (cost) | Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income (expense), net	(0.3)	(0.3)	(0.5)
Foreign exchange contracts | Gains (losses) on hedging instruments | Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss) attributable to TechnipFMC plc	3.6	(25.3)	11.8
Cash flow hedging | Foreign exchange contracts | Gains (losses) on hedging instruments | Amount Reclassified out of Accumulated Other Comprehensive Loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Revenue	(12.6)	(7.4)	(29.7)
Costs of sales	25.6	(14.5)	10.7
Selling, general and administrative expense	(0.4)	(0.3)	0.2
Other Income (expense), net	(5.5)	(13.1)	32.9
Income before income taxes	7.1	(35.3)	14.1
Provision (benefit) for income taxes	$ 3.5	$ (10.0)	$ 2.3