Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Employee benefits	$ 660	$ 348
Environmental remediation	111	16
Debt financing	39	0
Net operating loss carryforwards	17	12
Foreign currency	28	13
Tax credit carryforwards	21	0
Other	88	31
Total deferred tax assets	964	420
Deferred tax liabilities:
Property, plant and equipment	2,830	1,603
Inventories	678	473
Investments in subsidiaries and affiliates	2,130	912
Intangibles	97	70
Other	64	3
Total deferred tax liabilities	5,799	3,061
Net deferred tax liabilities	$ 4,835	$ 2,641