Information Relating to the Consolidated Statement of Cash Flows - Summary of Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Net decrease (increase) in operating working capital was composed of the following:
Decrease (increase) in accounts and notes receivable	$ 910	$ (1,379)
Decrease (increase) in inventories	(878)	(1,075)
Decrease (increase) in prepaid expenses and other current assets	(303)	(433)
Increase (decrease) in accounts payable and accrued liabilities	284	704
Increase (decrease) in income and other taxes payable	(292)	(104)
Net decrease (increase) in operating working capital	(279)	(2,287)
Net cash provided by operating activities includes the following cash payments:
Interest on debt (net of capitalized interest)	443	373
Income taxes	2,590	2,335
Proceeds and deposits related to asset sales and returns of investment consisted of the following gross amounts:
Proceeds and deposits related to asset sales	891	693
Returns of investment from equity affiliates	46	96
Proceeds and deposits related to asset sales and returns of investment	937	789
Net maturities (investments) of time deposits consisted of the following gross amounts:
Investments in time deposits	0	0
Time deposits matured	950	0
Net sales (purchases) of time deposits	950	0
Net sales (purchases) of marketable securities consisted of the following gross amounts:
Marketable securities purchased	(1)	(49)
Marketable securities sold	3	0
Net sales (purchases) of marketable securities	2	(49)
Net repayment (borrowing) of loans by equity affiliates:
Borrowing of loans by equity affiliates	(675)	0
Repayment of loans by equity affiliates	55	52
Net repayment (borrowing) of loans by equity affiliates	(620)	52
Net borrowings (repayments) of short-term obligations consisted of the following gross and net amounts:
Proceeds from issuances of short-term obligations	614	1,771
Repayments of short-term obligations	(366)	(2,212)
Net borrowings (repayments) of short-term obligations with three months or less maturity	(437)	5,142
Net borrowings (repayments) of short-term obligations	(189)	4,701
Capital expenditures
Additions to properties, plant and equipment	6,381	6,097
Additions to investments	40	21
Current-year dry hole expenditures	103	105
Payments for other assets and liabilities, net	13	0
Capital expenditures	6,537	6,223
Expensed exploration expenditures	207	229
Assets acquired through finance lease obligations and other financing obligations	147	65
Payments for other assets and liabilities, net	(13)	0
Capital and exploratory expenditures, excluding equity affiliates	6,878	6,517
Company's share of expenditures by equity affiliates	3,144	2,704
Capital and exploratory expenditures, including equity affiliates	$ 10,022	$ 9,221