Business Combination Transactions (Narrative) (Details) € in Millions			3 Months Ended		12 Months Ended
		Apr. 18, 2018 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 07, 2020 EUR (€) shares	Jan. 29, 2018 Rate
Business Acquisition [Line Items]
Other Asset Impairment Charges					$ 204,000,000.0	$ 495,400,000
Goodwill, Purchase Accounting Adjustments						9,900,000
Merger transaction and integration costs						$ 31,200,000	$ 36,500,000
Marketable Securities | €								€ 15
Investment Owned, Balance, Shares | shares								638,297
Percentage of capital owned								0.0229
Technip Odebrecht PLSV CV [Member]
Business Acquisition [Line Items]
Acquired assets			$ 391,000,000.0
Vessels acquired			335,200,000
Liability assumed			239,900,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt			203,100,000
Business Combination, Separately Recognized Transactions, Net Gains and Losses			(900,000)
Other Asset Impairment Charges			84,200,000
Business Combination, Bargain Purchase, Gain Recognized, Amount			$ 83,300,000
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred							$ 62,500,000
Island Offshore Subsea AS
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners									51.00%
Technip Offshore Finland Oy [Member]
Business Acquisition [Line Items]
Gain (Loss) on Disposition of Stock in Subsidiary				$ 27,800,000
Noncontrolling Interest | Island Offshore Subsea AS
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners | Rate									51.00%
Payments to Acquire Businesses, Gross		$ 42,400,000
Goodwill, Acquired During Period		$ 85,000,000.0
Subsea [Member]
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments	[1]				$ (21,200,000)
Technip Odebrecht PLSV CV [Member] | Subsea [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage			50.00%

[1] Beginning in the first quarter of 2020, Technip Energies includes our Loading Systems business that was previously reported in the Surface Technologies segment and our process automation business, Cybernetix, that was previously reported in the Subsea segment. See Note 7 for further details.