Accounting For Certain Long-Lived Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Amortization and impairments of unproved oil and gas property costs including amortization of capitalized interest	$ 288	$ 168	$ 115
United States
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Pretax impairment charges on proved oil and gas properties, other property, plant and equipment and other assets	6,130	171	73
Trinidad
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Pretax impairment charges on proved oil and gas properties, other property, plant and equipment and other assets			14
Other International [Member]
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Pretax impairment charges on proved oil and gas properties, other property, plant and equipment and other assets	$ 196	$ 404	$ 85