Effects of Restatement on Condensed Consolidated Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	$ (15.2)	$ 120.6
Comprehensive income	51.8	91.9
Comprehensive income attributable to TechnipFMC plc	48.1	92.8
Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	194.3	147.3
Comprehensive income	261.3	118.6
Comprehensive income attributable to TechnipFMC plc	257.6	119.5
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	(209.5)	(26.7)
Comprehensive income	(209.5)	(26.7)
Comprehensive income attributable to TechnipFMC plc	$ (209.5)	$ (26.7)

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Other Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831270

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Comprehensive Income
-URI http://asc.fasb.org/extlink&oid=51831223

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e557-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=51831255

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

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