Revenue - Disaggregation of Revenue, Geographical (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Lease revenue	$ 24.9	$ 52.6	$ 75.9	$ 115.2
Total revenue	3,158.5	3,434.2	6,288.8	6,347.2
Services
Disaggregation of Revenue [Line Items]
Revenue	2,315.2	2,548.8	4,622.9	4,599.9
Products
Disaggregation of Revenue [Line Items]
Revenue	818.4	832.8	1,590.0	1,632.1
Subsea
Disaggregation of Revenue [Line Items]
Revenue	1,368.2	1,488.5	2,601.8	2,645.9
Lease revenue	10.3	20.2	29.8	48.1
Subsea | Services
Disaggregation of Revenue [Line Items]
Revenue	764.2	970.2	1,481.7	1,615.8
Subsea | Products
Disaggregation of Revenue [Line Items]
Revenue	604.0	518.3	1,120.1	1,030.1
Subsea | Europe, Russia, Central Asia
Disaggregation of Revenue [Line Items]
Revenue	426.5	459.6	849.6	859.2
Subsea | Americas
Disaggregation of Revenue [Line Items]
Revenue	507.9	341.8	944.4	718.9
Subsea | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue	185.5	177.7	323.1	277.4
Subsea | Africa
Disaggregation of Revenue [Line Items]
Revenue	168.2	373.8	382.8	519.6
Subsea | Middle East
Disaggregation of Revenue [Line Items]
Revenue	80.1	135.6	101.9	270.8
Technip Energies
Disaggregation of Revenue [Line Items]
Revenue	1,538.3	1,505.0	3,086.0	2,840.1
Lease revenue	0.0	0.0	0.0	0.0
Technip Energies | Services
Disaggregation of Revenue [Line Items]
Revenue	1,520.6	1,505.0	3,054.7	2,840.1
Technip Energies | Products
Disaggregation of Revenue [Line Items]
Revenue	17.7	0.0	31.3	0.0
Technip Energies | Europe, Russia, Central Asia
Disaggregation of Revenue [Line Items]
Revenue	645.8	651.2	1,253.1	1,292.8
Technip Energies | Americas
Disaggregation of Revenue [Line Items]
Revenue	298.8	196.9	595.5	357.3
Technip Energies | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue	264.8	275.5	548.6	577.4
Technip Energies | Africa
Disaggregation of Revenue [Line Items]
Revenue	202.1	111.1	411.9	171.5
Technip Energies | Middle East
Disaggregation of Revenue [Line Items]
Revenue	126.8	270.3	276.9	441.1
Surface Technologies
Disaggregation of Revenue [Line Items]
Revenue	227.1	388.1	525.1	746.0
Lease revenue	14.6	32.4	46.1	67.1
Surface Technologies | Services
Disaggregation of Revenue [Line Items]
Revenue	30.4	73.6	86.5	144.0
Surface Technologies | Products
Disaggregation of Revenue [Line Items]
Revenue	196.7	314.5	438.6	602.0
Surface Technologies | Europe, Russia, Central Asia
Disaggregation of Revenue [Line Items]
Revenue	48.3	60.0	98.6	115.8
Surface Technologies | Americas
Disaggregation of Revenue [Line Items]
Revenue	81.1	199.9	230.4	393.1
Surface Technologies | Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue	28.0	44.1	62.3	89.1
Surface Technologies | Africa
Disaggregation of Revenue [Line Items]
Revenue	14.7	14.9	28.3	26.2
Surface Technologies | Middle East
Disaggregation of Revenue [Line Items]
Revenue	55.0	69.2	105.5	121.8
Operating Segments | Subsea
Disaggregation of Revenue [Line Items]
Total revenue	1,378.5	1,508.7	2,631.6	2,694.0
Operating Segments | Technip Energies
Disaggregation of Revenue [Line Items]
Total revenue	1,538.3	1,505.0	3,086.0	2,840.1
Operating Segments | Surface Technologies
Disaggregation of Revenue [Line Items]
Total revenue	$ 241.7	$ 420.5	$ 571.2	$ 813.1