STOCKHOLDERS’ EQUITY - Reclassification out of accumulated other comprehensive income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	$ (12.3)	$ (1.3)
Revenue	2,042.0	1,717.4
Income before income taxes	210.6	45.2
Provision for income taxes	49.7	37.4
Net income attributable to TechnipFMC plc	157.1	0.4
Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	(10.5)	0.0
Release of CTA loss | Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	(10.5)	0.0
Defined Pension  and Other Post-Retirement Benefits | Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Income before income taxes	0.1	(3.3)
Provision for income taxes	1.0	(1.0)
Net income attributable to TechnipFMC plc	(0.9)	(2.3)
Amortization of prior service credit (cost) | Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	(0.1)	(0.1)
Amortization of net actuarial loss | Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	(2.1)	(3.2)
Reclassification adjustment for net gain included in net income | Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	2.3	0.0
Foreign exchange contracts | Gains (losses) on hedging instruments | Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Net income attributable to TechnipFMC plc	3.1	(1.6)
Cash Flow Hedging | Foreign exchange contracts | Gains (losses) on hedging instruments | Amount Reclassified out of Accumulated Other Comprehensive Income (Loss)
Reclassification out of Accumulated Other Comprehensive Income
Other income (expense), net	2.8	(4.1)
Revenue	0.9	(1.7)
Cost of sales	0.6	3.5
Income before income taxes	4.3	(2.3)
Provision for income taxes	$ 1.2	$ (0.7)