REPORTABLE SEGMENTS (Details) $ in Millions		3 Months Ended
	Mar. 31, 2022 USD ($) segment	Mar. 31, 2022 USD ($) segment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segment results
Number of segments | segment	2	2
Total Operating Revenue		$ 1,165.5	$ 711.8
Operating Income		432.6	120.2
Interest expense, net		(4.8)	(7.3)
Other income (expense), net		2.0	1.4
Income before Income Taxes		429.8	114.3
Income taxes		(90.6)	(27.1)
Net Income		339.2	87.2
Deferred dry-docking amortization		6.7	6.6
Assets	$ 3,977.5	3,977.5		$ 3,693.1
Income from SSAT		34.0	9.2
SSAT
Segment results
Income from SSAT		34.0	9.2
Intersegment Eliminations
Segment results
Total Operating Revenue		73.2	33.7
Ocean Transportation
Segment results
Total Operating Revenue		943.9	560.5
Operating Income		416.2	114.1
Income from SSAT		34.0	9.2
Ocean Transportation | Intersegment Eliminations
Segment results
Total Operating Revenue		21.8	15.1
Logistics
Segment results
Total Operating Revenue		221.6	151.3
Operating Income		16.4	6.1
Logistics | Intersegment Eliminations
Segment results
Total Operating Revenue		$ 51.4	$ 18.6