Supplementary Oil and Gas Disclosure (Unaudited) - Changes in Standardized Measure (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Beginning of the Period	$ 4,436	$ 5,981	$ 4,754
Revision of Previous Estimates [Abstract]
Changes in Prices and Costs	979	(1,528)	1,002
Changes in Quantities	459	(404)	(896)
Changes in Future Development Costs	(259)	273	(141)
Development Costs Incurred During The Period	758	594	700
Additions to proved reserves resulting from extensions, discoveries and improved recovery, less related costs	1,061	815	1,964
Purchases and sales of reserves in place, net	13	(758)	(93)
Accretion of Discount	585	683	679
Sales of oil and gas, net of production costs	(1,349)	(1,631)	(1,281)
Net change in income taxes	(819)	773	(389)
Production timing and other	(31)	(362)	(318)
Net increase (decrease)	1,397	(1,545)	1,227
Ending Balance	5,833	4,436	5,981
Domestic [Member]
Beginning of the Period	3,408	4,724	4,058
Revision of Previous Estimates [Abstract]
Changes in Prices and Costs	944	(1,490)	728
Changes in Quantities	81	(427)	(829)
Changes in Future Development Costs	(83)	294	(31)
Development Costs Incurred During The Period	549	434	499
Additions to proved reserves resulting from extensions, discoveries and improved recovery, less related costs	1,012	791	1,366
Purchases and sales of reserves in place, net	13	(758)	(93)
Accretion of Discount	470	542	591
Sales of oil and gas, net of production costs	(973)	(1,129)	(1,048)
Net change in income taxes	(815)	650	(222)
Production timing and other	22	(223)	(295)
Net increase (decrease)	1,220	(1,316)	666
Ending Balance	4,628	3,408	4,724
Malaysia [Member]
Beginning of the Period	416	692	557
Revision of Previous Estimates [Abstract]
Changes in Prices and Costs	33	(14)	191
Changes in Quantities	76	23	(60)
Changes in Future Development Costs	(126)	(19)	(110)
Development Costs Incurred During The Period	79	93	188
Additions to proved reserves resulting from extensions, discoveries and improved recovery, less related costs	49	0	101
Purchases and sales of reserves in place, net	0	0	0
Accretion of Discount	33	64	71
Sales of oil and gas, net of production costs	(330)	(439)	(197)
Net change in income taxes	59	119	(26)
Production timing and other	14	(103)	(23)
Net increase (decrease)	(113)	(276)	135
Ending Balance	303	416	692
China [Member]
Beginning of the Period	612	565	139
Revision of Previous Estimates [Abstract]
Changes in Prices and Costs	2	(24)	83
Changes in Quantities	302	0	(7)
Changes in Future Development Costs	(50)	(2)	0
Development Costs Incurred During The Period	130	67	13
Additions to proved reserves resulting from extensions, discoveries and improved recovery, less related costs	0	24	497
Purchases and sales of reserves in place, net	0	0	0
Accretion of Discount	82	77	17
Sales of oil and gas, net of production costs	(46)	(63)	(36)
Net change in income taxes	(63)	4	(141)
Production timing and other	(67)	(36)	0
Net increase (decrease)	290	47	426
Ending Balance	$ 902	$ 612	$ 565