Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
	Sep. 26, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues		$ 4,908	$ 4,310	$ 14,944	$ 11,362
Cost of sales:
Production and delivery		3,069	2,794	8,792	7,462
Depreciation, depletion and amortization		458	418	1,351	1,257
Total cost of sales		3,527	3,212	10,143	8,719
Selling, general and administrative expenses		101	104	341	362
Mining exploration and research expenses		27	27	72	60
Environmental obligations and shutdown costs		8	72	76	76
Net gain on sales of assets		(70)	(33)	(126)	(66)
Total costs and expenses		3,593	3,382	10,506	9,151
Operating income		1,315	928	4,438	2,211
Interest expense, net		(143)	(304)	(436)	(633)
Net gain on early extinguishment of debt		0	11	8	8
Other income (expense), net		14	(9)	63	(9)
Income from continuing operations before income taxes and equity in affiliated companies’ net earnings		1,186	626	4,073	1,577
Provision for income taxes		(522)	(387)	(1,543)	(747)
Equity in affiliated companies’ net earnings		4	3	5	6
Net income from continuing operations		668	242	2,535	836
Net (loss) income from discontinued operations		(4)	3	(19)	50
Net income		664	245	2,516	886
Net (income) loss attributable to noncontrolling interests:
Continuing operations		(108)	35	(399)	(106)
Net income from discontinued operations attributable to noncontrolling interests		0	0	0	(4)
Net income attributable to common stockholders		$ 556	$ 280	$ 2,117	$ 776
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share		$ 0.38	$ 0.19	$ 1.47	$ 0.50
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share		0.00	0.00	(0.01)	0.03
Earnings Per Share, Basic		0.38	0.19	1.46	0.53
Earnings Per Share, Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Diluted Share		0.38	0.19	1.46	0.50
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share		0.00	0.00	(0.01)	0.03
Earnings Per Share, Diluted		$ 0.38	$ 0.19	$ 1.45	$ 0.53
Basic weighted-average shares of common stock outstanding		1,450	1,448	1,449	1,447
Diluted weighted-average shares of common shares outstanding		1,458	1,454	1,458	1,453
Dividends declared per share of common stock	$ 0.05	$ 0.05	$ 0	$ 0.15	$ 0