Information Relating to the Consolidated Statement of Cash Flows (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017
Net decrease (increase) in operating working capital
Decrease (increase) in accounts and notes receivable		$ (1,741)	$ 265
Decrease (increase) in inventories		(749)	(436)
Decrease (increase) in prepaid expenses and other current assets		(310)	235
Increase (decrease) in accounts payable and accrued liabilities		887	(621)
Increase (decrease) in income and other taxes payable		31	9
Net decrease (increase) in operating working capital	[1]	(1,882)	(548)
Cash Payment for Interest on Debt and For Income Taxes
Interest on debt (net of capitalized interest)		502	30
Income taxes		3,526	2,203
Net sales of marketable securities
Marketable securities purchased		(51)	(3)
Marketable securities sold		0	3
Net sales (purchases) of marketable securities		(51)	0
Net borrowing of loans by equity affiliates
Borrowing of loans by equity affiliates		0	(142)
Repayment of loans by equity affiliates		78	106
Net repayment (borrowing) of loans by equity affiliates		78	(36)
Net (repayments) borrowings of short-term obligations
Repayments of short-term obligations		(3,379)	(8,403)
Proceeds from issuances of short-term obligations		2,452	3,415
Net borrowings (repayments) of short-term obligations with three months or less maturity		3,126	(2,197)
Net borrowings (repayments) of short-term obligations		2,199	(7,185)
Capital expenditures
Additions to properties, plant and equipment		9,489	9,615
Additions to investments		36	16
Current year dry hole expenditures		276	131
Payments for other liabilities and assets, net		0	1
Capital expenditures		9,801	9,763
Expensed exploration expenditures		364	368
Assets acquired through capital lease obligations		65	3
Capital and exploratory expenditures, excluding equity affiliates		10,230	10,134
Company’s share of expenditures by equity affiliates		4,115	3,252
Capital and exploratory expenditures, including equity affiliates		$ 14,345	$ 13,386

[1] 2017 adjusted to conform to Accounting Standards Update 2016-18. Refer to Note 4, "Information Relating to the Consolidated Statement of Cash Flows" beginning on page 8.