Income Taxes (Deferred Income Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Allowance for doubtful accounts	$ 24	$ 19
Inventories	99	73
Pension and postretirement benefits	259	231
Environmental and regulatory compliance	27	22
Other accruals and prepayments	341	195
Stock-based compensation expense	68	69
Operating lease liabilities	215	194
Tax credit and loss carryforwards	569	703
Valuation allowances	(264)	(261)
Total deferred tax asset	1,338	1,245
Deferred tax liabilities:
Property, plant and equipment	(50)	(113)
Insurance, including self-insurance	(713)	(272)
Basis difference in LYONs	(11)	(14)
Operating lease ROU assets	(204)	(186)
Goodwill and other intangibles	(3,814)	(2,312)
Total deferred tax liability	(4,792)	(2,897)
Net deferred tax liability	$ (3,454)	$ (1,652)