Taxes (Details 2) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes to company's unrecognized tax benefits
Balance at January 1		$ 3,042	$ 3,552	$ 3,848
Foreign currency effects		1	(27)	(25)
Additions based on tax positions taken in current year		245	154	354
Additions/reductions resulting from current-year asset acquisitions/sales		0	0	(22)
Additions for tax positions taken in prior years		181	218	37
Reductions for tax positions taken in prior years		(390)	(678)	(561)
Settlements with taxing authorities in current year		(36)	(5)	(50)
Reductions as a result of a lapse of the applicable statute of limitations		(12)	(172)	(29)
Balance at December 31		3,031	3,042	3,552
Income Tax Authority [Line Items]
Excise and similar taxes on products and merchandise		6,905	7,359	8,186
Import duties and other levies	[1]	11,668	12,030	12,540
Total taxes other than on income		11,668	12,030	12,540
United States
Income Tax Authority [Line Items]
Excise and similar taxes on products and merchandise		4,335	4,426	4,633
Import duties and other levies		9	4	6
Property and other miscellaneous taxes		1,680	1,367	1,002
Payroll taxes		252	270	273
Taxes on production		159	157	349
Total taxes other than on income		6,435	6,224	6,263
International
Income Tax Authority [Line Items]
Excise and similar taxes on products and merchandise		2,570	2,933	3,553
Import duties and other levies		33	40	45
Property and other miscellaneous taxes		2,379	2,548	2,277
Payroll taxes		145	161	172
Taxes on production		106	124	230
Total taxes other than on income		$ 5,233	$ 5,806	$ 6,277

[1] Includes excise, value-added and similar taxes. $6,905; $7,359; $8,186.