CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net sales (Note 3)	$ 1,692	$ 2,065	$ 3,335	$ 3,930
Costs of sales	1,390	1,447	2,712	2,795
Gross margin	302	618	623	1,135
Selling expenses	21	23	42	46
General and administrative expenses	80	80	169	158
Research and development expenses	2	2	3	4
Other operating costs, net (Note 15)	13	37	49	47
Operating income	186	476	360	880
Non-operating pension and other postretirement benefit costs	(10)	(13)	(480)	(37)
Interest income and other	6	11	16	23
Interest expense, net of capitalized interest	(91)	(92)	(198)	(185)
Earnings (loss) before income taxes	91	382	(302)	681
Income taxes (Note 16)	37	(65)	141	(95)
Net earnings (loss)	$ 128	$ 317	$ (161)	$ 586
Earnings (loss) per share, basic and diluted (Note 4)	$ 0.17	$ 0.42	$ (0.22)	$ 0.77
Weighted average shares outstanding (in thousands) (Note 4):
Basic	745,486	757,829	746,041	757,317
Diluted	746,232	760,533	746,041	759,992