STOCKHOLDERS’ EQUITY -Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 3,276.7	$ 3,418.4
Other comprehensive income (loss), net of tax	11.6	120.1
Ending balance	3,242.7	3,490.4
Foreign Currency Translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,177.7)	(1,158.4)
Other comprehensive income (loss) before reclassifications, net of tax	17.9	125.3
Reclassification adjustment for net losses included in net income (loss), net of tax	(0.1)	0.0
Other comprehensive income (loss), net of tax	17.8	125.3
Ending balance	(1,159.9)	(1,033.1)
Hedging
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(17.1)	(17.3)
Other comprehensive income (loss) before reclassifications, net of tax	(6.1)	(14.9)
Reclassification adjustment for net losses included in net income (loss), net of tax	1.6	6.4
Other comprehensive income (loss), net of tax	(4.5)	(8.5)
Ending balance	(21.6)	(25.8)
Defined Pension  and Other Post-Retirement Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(106.9)	(129.3)
Other comprehensive income (loss) before reclassifications, net of tax	(2.0)	(0.2)
Reclassification adjustment for net losses included in net income (loss), net of tax	2.3	3.1
Other comprehensive income (loss), net of tax	0.3	2.9
Ending balance	(106.6)	(126.4)
Accumulated Other Comprehensive  Loss Attributable to TechnipFMC plc
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,301.7)	(1,305.0)
Other comprehensive income (loss) before reclassifications, net of tax	9.8	110.2
Reclassification adjustment for net losses included in net income (loss), net of tax	3.8	9.5
Other comprehensive income (loss), net of tax	13.6	119.7
Ending balance	(1,288.1)	(1,185.3)
Accumulated Other Comprehensive  Loss Attributable to Non-Controlling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(9.8)	(5.7)
Other comprehensive income (loss) before reclassifications, net of tax	(2.0)	0.4
Reclassification adjustment for net losses included in net income (loss), net of tax	0.0	0.0
Other comprehensive income (loss), net of tax	(2.0)	0.4
Ending balance	$ (11.8)	$ (5.3)