Condensed Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Net income (loss)		$ 6.4	$ (115.3)	$ (3,224.0)	$ 18.2
Foreign currency translation adjustments
Foreign currency translation adjustments(a)	[1]	(10.4)	(42.5)	(213.2)	(43.8)
Net gains (losses) on hedging instruments
Net gains (losses) arising during the period		44.7	(37.3)	(10.6)	(32.1)
Reclassification adjustment for net (gains) losses included in net income		3.9	(17.1)	8.7	(10.7)
Net gains (losses) on hedging instruments(b)	[2]	48.6	(54.4)	(1.9)	(42.8)
Pension and other post-retirement benefits:
Net gains (losses) arising during the period		(2.6)	0.4	(0.4)	1.4
Reclassification adjustment for amortization of prior service cost included in net income		0.3	0.9	0.8	2.3
Reclassification adjustment for amortization of net actuarial loss included in net income		2.3	0.0	6.7	0.0
Net pension and other postretirement benefits(c)	[3]	0.0	1.3	7.1	3.7
Other comprehensive income (losses), net of tax		38.2	(95.6)	(208.0)	(82.9)
Comprehensive income (loss)		44.6	(210.9)	(3,432.0)	(64.7)
Comprehensive (income) loss attributable to non-controlling interest		(11.8)	0.6	(17.9)	(16.3)
Comprehensive income (loss) attributable to TechnipFMC plc		32.8	(210.3)	(3,449.9)	(81.0)
Foreign currency translation adjustments, tax (expense) benefit		0.0	7.9	0.0	7.9
Net gains (losses) on hedging instruments, tax (expense) benefit		(13.1)	14.4	2.7	14.1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax		$ 1.7	$ (0.2)	$ (0.2)	$ 0.4

[1] Net of income tax benefit of nil and $7.9 million for the three months ended September 30, 2020 and 2019, respectively, and nil and $7.9 million for the nine months ended September 30, 2020 and 2019, respectively

[2] Net of income tax (expense) benefit of $(13.1) million and $14.4 million for the three months ended September 30, 2020 and 2019, respectively, and $2.7 million and $14.1 million for the nine months ended September 30, 2020 and 2019, respectively.

[3] Net of income tax (expense) benefit of $1.7 million and $(0.2) million for the three months ended September 30, 2020 and 2019, respectively, and $0.2 million and $0.4 million for the nine months ended September 30, 2020 and 2019, respectively.