Share-Based Compensation (Narrative) (Details) - TechnipFMC plc Incentive Award Plan - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 11, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares authorized (in shares)					24,100,000
Stock-based compensation expense for nonvested stock units	$ 14.2	$ 19.9	$ 52.6	$ 61.4

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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