Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues	$ 2,798	$ 3,792
Cost of sales:
Production and delivery	2,545	2,919
Depreciation, depletion and amortization	341	347
Metals inventory adjustments	222	57
Total cost of sales	3,108	3,323
Selling, general and administrative expenses	110	112
Mining exploration and research expenses	16	27
Environmental obligations and shutdown costs	26	42
Net loss (gain) on sales of assets	11	(33)
Total costs and expenses	3,271	3,471
Operating (loss) income	(473)	321
Interest expense, net	(127)	(146)
Net loss on early extinguishment of debt	(32)	(6)
Other income, net	20	14
(Loss) income from continuing operations before income taxes and equity in affiliated companies’ net earnings (losses)	(612)	183
Benefit from (provision for) income taxes	60	(105)
Equity in affiliated companies’ net earnings (losses)	3	(3)
Net (loss) income from continuing operations	(549)	75
Net gain from discontinued operations	0	1
Net income	(549)	76
Net (income) loss attributable to noncontrolling interests:
Continuing operations	58	(45)
Net (loss) income attributable to common stockholders	$ (491)	$ 31
Earnings Per Share, Basic and Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Basic and Diluted Share	$ (0.34)	$ 0.02
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share	0	0
Earnings Per Share, Basic and Diluted	$ (0.34)	$ 0.02
Basic weighted-average shares of common stock outstanding	1,452	1,451
Diluted weighted-average shares of common shares outstanding	1,452	1,457
Dividends declared per share of common stock (in dollars per share)	$ 0	$ 0.05