CONSOLIDATED INTERIM STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Net sales (Note 3)	$ 477	$ 802	$ 1,222	$ 1,637
Cost of goods sold	393	620	996	1,259
Gross profit	84	182	226	378
Selling, general and administrative expenses	51	58	112	118
Other expense, net (Note 5)	15	17	31	36
Interest expense	20	18	36	34
Non-operating (income) expense	(4)	2	(8)	6
Income before taxes	2	87	55	184
Tax expense (Note 6)	11	21	12	45
Net (loss) income	$ (9)	$ 66	$ 43	$ 139
Earnings (loss) per common share
Basic	$ (0.12)	$ 0.88	$ 0.57	$ 1.87
Diluted	$ (0.12)	$ 0.86	$ 0.57	$ 1.83
Weighted average common shares outstanding
Basic	75,595,991	74,591,478	75,316,827	74,414,450
Diluted	75,845,511	76,900,544	75,837,459	76,129,821