EARNINGS (LOSS) PER SHARE - Reconciliation of Number of Shares Used for Basic and Diluted Earnings Per Share ("EPS") Calculation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share
Income (loss) from continuing operations attributable to TechnipFMC plc	$ (87.2)	$ 2.1	$ (86.8)	$ (40.2)
Loss from discontinued operations attributable to TechnipFMC plc	0.0	0.0	0.0	(19.4)
Net income (loss) attributable to TechnipFMC plc	$ (87.2)	$ 2.1	$ (86.8)	$ (59.6)
Weighted average number of shares outstanding (in shares)	440.1	452.2	441.1	451.6
Total shares and dilutive securities (in shares)	440.1	456.8	441.1	451.6
Earnings (loss) per share from continuing operations attributable to TechnipFMC plc Basic (usd per share)	$ (0.20)	$ 0.00	$ (0.20)	$ (0.09)
Earnings (loss) per share from continuing operations attributable to TechnipFMC plc Diluted (usd per share)	(0.20)	0.00	(0.20)	(0.09)
Earnings (loss) per share from discontinued operations attributable to TechnipFMC plc basic (usd per share)	0.00	0.00	0.00	(0.04)
Earnings (loss) per share from discontinued operations attributable to TechnipFMC plc diluted (usd per share)	0.00	0.00	0.00	(0.04)
Total earnings (loss) per share attributable to TechnipFMC plc Basic (usd per share)	(0.20)	0.00	(0.20)	(0.13)
Total earnings (loss) per share attributable to TechnipFMC plc Diluted (usd per share)	$ (0.20)	$ 0.00	$ (0.20)	$ (0.13)
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	2.6	3.3	2.3	4.4
Share option awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	1.4	1.6	1.4	1.6
Restricted share units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	0.0	0.0	0.0	1.6
Performance shares
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	1.2	1.7	0.9	1.2
Restricted share units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Dilutive effect of restricted stock units (in shares)	0.0	4.6	0.0	0.0
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	11.6		12.7	4.6