INVENTORIES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Inventory [Line Items]
Crude oil and feedstocks	$ 1,277.7		$ 1,277.7		$ 1,018.9
Refined products and blendstocks	1,414.5		1,414.5		1,200.2
Warehouse stock and other	139.2		139.2		136.7
Inventory, Gross	2,831.4		2,831.4		2,355.8
Lower of cost or market adjustment	0.0		0.0		(669.6)
Total inventories	2,831.4		2,831.4		1,686.2
Income (Loss) from Operations	54.3	$ (397.7)	165.1	$ (1,241.2)
Scenario, Adjustment [Member]
Inventory [Line Items]
Lower of cost or market adjustment	0.0	(1,093.1)	0.0	(1,093.1)	(669.6)	$ (1,103.0)	$ (401.6)
Income (Loss) from Operations		$ 9.9	669.6	$ 691.5
Titled Inventory [Member]
Inventory [Line Items]
Crude oil and feedstocks	1,277.7		1,277.7		1,018.9
Refined products and blendstocks	1,059.0		1,059.0		933.7
Warehouse stock and other	139.2		139.2		136.7
Inventory, Gross	2,475.9		2,475.9		2,089.3
Lower of cost or market adjustment	0.0		0.0		(572.4)
Total inventories	2,475.9		2,475.9		1,516.9
Inventory Supply and Offtake Arrangements [Member]
Inventory [Line Items]
Crude oil and feedstocks	0.0		0.0		0.0
Refined products and blendstocks	355.5		355.5		266.5
Warehouse stock and other	0.0		0.0		0.0
Inventory, Gross	355.5		355.5		266.5
Lower of cost or market adjustment	0.0		0.0		(97.2)
Total inventories	$ 355.5		$ 355.5		$ 169.3