Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 3,851	$ 3,153	$ 9,703	$ 10,491
Cost of sales:
Production and delivery	2,465	2,670	7,404	8,599
Depreciation, depletion and amortization	394	322	1,093	1,021
Metals inventory adjustments	9	41	92	100
Total cost of sales	2,868	3,033	8,589	9,720
Selling, general and administrative expenses	72	101	273	300
Mining exploration and research expenses	8	25	42	83
Environmental obligations and shutdown costs	21	20	58	85
Net loss (gain) on sales of assets	2	12	13	(13)
Total costs and expenses	2,971	3,191	8,975	10,175
Operating income (loss)	880	(38)	728	316
Interest expense, net	(120)	(123)	(362)	(401)
Net loss on early extinguishment of debt	(59)	(21)	(100)	(27)
Other income, net	22	33	62	52
Income (loss) from continuing operations before income taxes and equity in affiliated companies’ net earnings	723	(149)	328	(60)
Provision for income taxes	(297)	(91)	(333)	(181)
Equity in affiliated companies’ net earnings	6	5	12	7
Net income (loss) from continuing operations	432	(235)	7	(234)
Net gain from discontinued operations	0	1	0	2
Net income	432	(234)	7	(232)
Net (income) loss attributable to noncontrolling interests:
Continuing operations	(103)	27	(116)	(16)
Net income (loss) attributable to common stockholders	$ 329	$ (207)	$ (109)	$ (248)
Earnings Per Share, Basic and Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Basic and Diluted Share	$ 0.22	$ (0.15)	$ (0.08)	$ (0.17)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic and Diluted Share	0	0	0	0
Earnings Per Share, Basic and Diluted	$ 0.22	$ (0.15)	$ (0.08)	$ (0.17)
Basic weighted-average shares of common stock outstanding	1,453	1,452	1,453	1,451
Diluted weighted-average shares of common shares outstanding	1,461	1,452	1,453	1,451
Dividends declared per share of common stock (in dollars per share)	$ 0	$ 0.05	$ 0	$ 0.15