Information Relating to the Consolidated Statement of Cash Flows - Summary of Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Distributions more (less) than income from equity affiliates includes the following:
Distributions from equity affiliates	$ 1,209	$ 1,533
(Income) loss from equity affiliates	1,040	(3,430)
Distributions more (less) than income from equity affiliates	2,249	(1,897)
Net decrease (increase) in operating working capital was composed of the following:
Decrease (increase) in accounts and notes receivable	3,601	2,254
Decrease (increase) in inventories	201	(20)
Decrease (increase) in prepaid expenses and other current assets	632	(286)
Increase (decrease) in accounts payable and accrued liabilities	(3,609)	(981)
Increase (decrease) in income and other taxes payable	(846)	159
Net decrease (increase) in operating working capital	(21)	1,126
Net cash provided by operating activities includes the following cash payments:
Interest on debt (net of capitalized interest)	384	579
Income taxes	2,527	3,516
Proceeds and deposits related to asset sales and returns of investment consisted of the following gross amounts:
Proceeds and deposits related to asset sales	1,912	1,021
Returns of investment from equity affiliates	67	67
Proceeds and deposits related to asset sales and returns of investment	1,979	1,088
Net maturities (investments) of time deposits consisted of the following gross amounts:
Investments in time deposits	0	0
Maturities of time deposits	0	950
Net maturities of (investments in) time deposits	0	950
Net sales (purchases) of marketable securities consisted of the following gross amounts:
Marketable securities purchased	(2)	(1)
Marketable securities sold	37	3
Net sales (purchases) of marketable securities	35	2
Net repayment (borrowing) of loans by equity affiliates:
Borrowing of loans by equity affiliates	(3,925)	(1,050)
Repayment of loans by equity affiliates	2,491	80
Net repayment (borrowing) of loans by equity affiliates	(1,434)	(970)
Net borrowings (repayments) of short-term obligations consisted of the following gross and net amounts:
Proceeds from issuances of short-term obligations	8,863	1,821
Repayments of short-term obligations	(7,479)	(570)
Net borrowings (repayments) of short-term obligations with three months or less maturity	(1,990)	722
Net borrowings (repayments) of short-term obligations	(606)	1,973
Net sales (purchases) of treasury shares consists of the following gross and net amounts:
Shares issued for share-based compensation plans	206	944
Shares purchased under share repurchase and deferred compensation plans	(1,751)	(2,789)
Net sales (purchases) of treasury shares	(1,545)	(1,845)
Capital expenditures
Additions to properties, plant and equipment	6,576	9,713
Additions to investments	86	69
Current-year dry hole expenditures	226	111
Payments for other assets and liabilities, net	(33)	13
Capital expenditures	6,855	9,906
Expensed exploration expenditures	322	361
Assets acquired through finance lease obligations and other financing obligations	49	146
Payments for other assets and liabilities, net	33	(13)
Capital and exploratory expenditures, excluding equity affiliates	7,259	10,400
Company's share of expenditures by equity affiliates	3,063	4,578
Capital and exploratory expenditures, including equity affiliates	$ 10,322	$ 14,978