Impairment, Restructuring and Other Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring and Impairment
Impairment, restructuring and other expenses	$ 92.0	$ 140.3	$ 3,440.7	$ 166.0
Restructuring and Related Cost, Incurred Cost	24.3	14.0	85.9	38.5
COVID-19 expenses	36.4		101.8
Asset Impairment Charges	31.3	126.3	3,253.0	127.5
Subsea
Restructuring and Impairment
Impairment, restructuring and other expenses	43.4	131.2	2,912.8	138.0
Restructuring and Related Cost, Incurred Cost	7.1	4.9	36.1	11.1
COVID-19 expenses	18.7		50.1
Asset Impairment Charges	17.6	126.3	2,826.6	126.9
Technip Energies
Restructuring and Impairment
Impairment, restructuring and other expenses	36.1	5.2	78.8	11.1
Restructuring and Related Cost, Incurred Cost	15.1	5.2	29.1	11.1
COVID-19 expenses	15.3		44.0
Asset Impairment Charges	5.7	0.0	5.7	0.0
Surface Technologies
Restructuring and Impairment
Impairment, restructuring and other expenses	8.7	0.7	439.8	3.4
Restructuring and Related Cost, Incurred Cost	0.9	0.7	14.0	2.8
COVID-19 expenses	2.4		7.7
Asset Impairment Charges	5.4	0.0	418.1	0.6
Corporate and other
Restructuring and Impairment
Impairment, restructuring and other expenses	3.8	3.2	9.3	13.5
Restructuring and Related Cost, Incurred Cost	1.2	3.2	6.7	13.5
COVID-19 expenses	0.0		0.0
Asset Impairment Charges	$ 2.6	$ 0.0	$ 2.6	$ 0.0