Condensed Consolidated Statements Of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue
Lease revenue	$ 46.6	$ 24.9	$ 79.4	$ 75.9
Total revenue	1,668.8	1,620.2	3,300.8	3,202.8
Costs and expenses
Cost of lease revenue	36.8	24.1	63.0	62.1
Selling, general and administrative expense	172.6	157.8	320.2	353.1
Research and development expense	19.2	25.1	35.7	50.5
Impairment, restructuring and other expenses (Note 16)	2.0	103.6	27.5	3,302.7
Total costs and expenses	1,636.3	1,737.2	3,267.1	6,561.1
Other income (expense), net	(1.0)	(20.3)	34.6	(28.2)
Income from equity affiliates (Note 11)	12.8	15.7	20.5	36.8
Income (loss) from investment in Technip Energies (Note 11)	(146.8)	0.0	323.3	0.0
Income (loss) before net interest expense and income taxes	(102.5)	(121.6)	412.1	(3,349.7)
Interest income	2.7	18.9	6.8	28.7
Interest expense	(37.9)	(45.5)	(76.5)	(78.3)
Loss on early extinguishment of debt	0.0	0.0	(23.5)	0.0
Income (loss) before income taxes	(137.7)	(148.2)	318.9	(3,399.3)
Provision for income taxes (Note 18)	34.9	27.6	59.4	4.4
Income (loss) from continuing operations	(172.6)	(175.8)	259.5	(3,403.7)
Income from continuing operations attributable to non-controlling interests	(2.1)	(1.8)	(3.9)	(8.7)
Income (loss) from continuing operations attributable to TechnipFMC plc	(174.7)	(177.6)	255.6	(3,412.4)
Income (loss) from discontinued operations	7.7	191.1	(52.5)	173.3
Income from discontinued operations attributable to non-controlling interests	0.0	(1.8)	(1.9)	(5.3)
Net income (loss) attributable to TechnipFMC plc	$ (167.0)	$ 11.7	$ 201.2	$ (3,244.4)
Earnings Per Share, Basic and Diluted [Abstract]
Earnings (loss) per share from continuing operations basic (usd per share)	$ (0.39)	$ (0.40)	$ 0.57	$ (7.62)
Earnings (loss) per share from continued operations diluted (usd per share)	(0.39)	(0.40)	0.56	(7.62)
Earnings (loss) per share from discontinued operations basic (usd per share)	0.02	0.42	(0.12)	0.38
Earnings (loss) per share from discontinued operations diluted (usd per share)	0.02	0.42	(0.12)	0.38
Basic (usd per share)	(0.37)	0.03	0.45	(7.24)
Diluted (usd per share)	$ (0.37)	$ 0.03	$ 0.44	$ (7.24)
Weighted average shares outstanding (Note 6)
Basic (in shares)	450.6	448.3	450.4	447.9
Diluted (in shares)	450.6	448.3	454.9	447.9
Service revenue
Revenue
Revenue	$ 913.4	$ 793.9	$ 1,739.6	$ 1,567.5
Costs and expenses
Cost of goods and services sold	833.3	794.9	1,577.1	1,499.3
Products
Revenue
Revenue	708.8	801.4	1,481.8	1,559.4
Costs and expenses
Cost of goods and services sold	$ 572.4	$ 631.7	$ 1,243.6	$ 1,293.4