Litigation And Other Contingencies (Narrative) (Details) - USD ($) $ in Millions	Mar. 09, 2017	Oct. 09, 2014	Oct. 24, 2011	Jun. 27, 2007
Nigeria Production Sharing Contract Litigation [Member]
Litigation And Other Contingencies [Line Items]
Percent interest in Erha block PSC			56.25%
Pending Or Threatened Litigation [Member]
Litigation And Other Contingencies [Line Items]
Amount of award relating to excess lifting of crude oil			$ 1,800
Accrued interest relating to award for excess lifting of crude oil			$ 234
Expropriation Of Assets [Member] | Mobil Cerro Negro, Ltd. (MCN) [Member]
Litigation And Other Contingencies [Line Items]
Percentage ownership interest in Cerro Negro Project				41.67%
Cerro Negro award for breach of contractual obligations		$ 908
Annulled portion of award for Cerro Negro Project	$ 1,400
Award collected from Venezuela for Cerro Negro and La Ceiba Projects	$ 260