Employee Benefit Plans (Details 1) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheet for pension and other postretirement benefit plans
Noncurrent employee benefit plans	$ (7,935)	$ (8,412)
U.S. [Member]
Consolidated Balance Sheet for pension and other postretirement benefit plans
Deferred charges and other assets	13	13
Accrued liabilities	(153)	(123)
Noncurrent employee benefit plans	(3,149)	(3,050)
Net amount recognized at December 31	(3,289)	(3,160)
International [Member]
Consolidated Balance Sheet for pension and other postretirement benefit plans
Deferred charges and other assets	333	244
Accrued liabilities	(77)	(68)
Noncurrent employee benefit plans	(1,483)	(1,699)
Net amount recognized at December 31	(1,227)	(1,523)
Other Benefits [Member]
Consolidated Balance Sheet for pension and other postretirement benefit plans
Deferred charges and other assets	0	0
Accrued liabilities	(191)	(198)
Noncurrent employee benefit plans	(3,133)	(3,462)
Net amount recognized at December 31	$ (3,324)	$ (3,660)