Other Financial Information - Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Properties, Plants And Equipment
Proved properties	$ 122,796	$ 130,448
Unproved properties	7,410	8,951
Other	6,653	6,831
Gross properties, plants and equipment	136,859	146,230
Accumulated depreciation	(70,413)	(70,786)
Net properties, plants and equipment (net of accumulated depreciation, depletion and amortization of $70,413 million in 2015 and $70,786 million in 2014)	$ 66,446	75,444
Assets held for sale, formerly in proved properties		0
Assets held for sale, formerly in unproved properties		$ 0