Goodwill And Intangible Assets (Carrying Amount of Goodwill) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Asset Impairment Charges		$ 3,287.4		$ 2,484.1	$ 1,792.6
Goodwill [Roll Forward]
Beginning balance		5,598.3		7,607.6
Impairment		(3,083.4)		(1,988.7)
Goodwill, Purchase Accounting Adjustments				9.9
Goodwill, Other Increase (Decrease)				(17.7)
Translation		(2.4)		(12.8)
Ending balance		$ 2,512.5		5,598.3	7,607.6
Current Fiscal Year End Date		--12-31
Subsea [Member]
Goodwill [Line Items]
Asset Impairment Charges		$ 2,854.5		1,798.6	1,784.2
Goodwill [Roll Forward]
Beginning balance		2,814.1		4,142.4
Impairment		(2,747.5)		(1,321.9)	(1,383.0)
Goodwill, Purchase Accounting Adjustments	[1]	(21.2)
Translation		(45.4)		(6.4)
Ending balance				2,814.1	4,142.4
Surface Technologies [Member]
Goodwill [Line Items]
Asset Impairment Charges		419.3		685.5	4.5
Goodwill [Roll Forward]
Beginning balance		360.6		1,017.5
Impairment		(335.9)		(666.8)
Goodwill, Purchase Accounting Adjustments		(24.9)	[1]	9.9
Translation		0.2
Ending balance				360.6	1,017.5
Technip Energies
Goodwill [Line Items]
Asset Impairment Charges		10.3		0.0	0.0
Goodwill [Roll Forward]
Beginning balance		2,423.6		2,447.7
Impairment		0.0
Goodwill, Purchase Accounting Adjustments	[1]	46.1
Goodwill, Other Increase (Decrease)				(17.7)
Translation		42.8		(6.4)
Ending balance		$ 2,512.5		$ 2,423.6	$ 2,447.7

[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.