STOCKHOLDERS’ EQUITY - Accumulated other comprehensive loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 3,276.7	$ 3,418.4	$ 4,214.3
Reclassification adjustment for net (gains) losses included in net income, net of tax	(7.0)	(3.2)	0.0
Other comprehensive income (loss), net of tax	63.5	(0.8)	84.8
Ending balance	3,172.1	3,276.7	3,418.4
Foreign Currency Translation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,177.7)	(1,158.4)
Other comprehensive income (loss) before reclassifications, net of tax	64.2	(16.1)
Reclassification adjustment for net (gains) losses included in net income, net of tax		(3.2)
Other comprehensive income (loss), net of tax	57.2	(19.3)
Ending balance	(1,120.5)	(1,177.7)	(1,158.4)
Hedging
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(17.1)	(17.3)
Other comprehensive income (loss) before reclassifications, net of tax	41.6	(25.1)
Reclassification adjustment for net (gains) losses included in net income, net of tax	(3.6)	25.3
Other comprehensive income (loss), net of tax	38.0	0.2
Ending balance	20.9	(17.1)	(17.3)
Defined Pension  and Other Post-Retirement Benefits
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(106.9)	(129.3)
Other comprehensive income (loss) before reclassifications, net of tax	(44.7)	13.3
Reclassification adjustment for net (gains) losses included in net income, net of tax	9.2	9.1
Other comprehensive income (loss), net of tax	(35.5)	22.4
Ending balance	(142.4)	(106.9)	(129.3)
Accumulated Other Comprehensive  Loss Attributable to TechnipFMC plc
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,301.7)	(1,305.0)
Other comprehensive income (loss) before reclassifications, net of tax	61.1	(27.9)
Reclassification adjustment for net (gains) losses included in net income, net of tax	(1.4)	31.2
Other comprehensive income (loss), net of tax	59.7	3.3
Ending balance	(1,242.0)	(1,301.7)	(1,305.0)
Accumulated Other Comprehensive  Loss Attributable to Non-Controlling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(9.8)	(5.7)
Other comprehensive income (loss) before reclassifications, net of tax	3.8	(4.1)
Reclassification adjustment for net (gains) losses included in net income, net of tax	0.0	0.0
Other comprehensive income (loss), net of tax	3.8	(4.1)
Ending balance	$ (6.0)	$ (9.8)	$ (5.7)