Business Segments (Segment Assets) (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total Assets		$ 19,692.6	$ 23,518.8
Operating segments
Segment Reporting Information [Line Items]
Total Assets		13,613.2	17,519.4
Operating segments | Subsea [Member]
Segment Reporting Information [Line Items]
Total Assets		6,796.6	10,824.2
Operating segments | Surface Technologies [Member]
Segment Reporting Information [Line Items]
Total Assets		1,758.3	2,246.4
Operating segments | Technip Energies
Segment Reporting Information [Line Items]
Total Assets		5,058.3	4,448.8
Corporate
Segment Reporting Information [Line Items]
Total Assets	[1]	$ 6,079.4	$ 5,999.4

[1] Corporate includes cash, LIFO adjustments, deferred income tax balances, property, plant and equipment and intercompany eliminations not associated with a specific segment, pension assets and the fair value of derivative financial instruments.