Income Taxes (Components of deferred tax liabilties and assets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Liabilities
Properties, plants and equipment, and intangibles	$ 10,170	$ 7,744
Inventory	44	64
Other	213	242
Total deferred tax liabilities	10,427	8,050
Deferred Tax Assets
Benefit plan accruals	321	540
Asset retirement obligations and accrued environmental costs	2,297	2,262
Investments in joint ventures (Asset)	1,684	1,653
Other financial accruals and deferrals	827	907
Loss and credit carryforwards	7,402	8,904
Other	399	365
Total deferred tax assets	12,930	14,631
Less valuation allowance	(8,342)	(9,965)	$ (10,214)	$ (3,040)
Net deferred tax assets	4,588	4,666	$ 151
Total deferred tax liabilities	$ 5,839	$ 3,384