Supplementary Oil and Gas Disclosure (Unaudited) - Standardized Measure (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Cash Inflows	$ 30,485	$ 25,664	$ 31,205
Related Future [Abstract]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Production Costs	10,032	9,065	8,936
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs	4,457	4,233	4,635
DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesBeforeIncomeTaxExpense	15,996	12,366	17,634
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	5,833	4,436	5,981	4,754
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Income Tax Expense	4,594	3,091	4,822
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Net Cash Flows, Total	11,402	9,275	12,812
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, 10 Percent Annual Discount for Estimated Timing of Cash Flows	(5,569)	(4,839)	(6,831)
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	5,833	4,436	5,981
Domestic [Member]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Cash Inflows	26,600	21,724	26,241
Related Future [Abstract]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Production Costs	8,302	7,042	6,523
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs	4,166	3,949	4,246
DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesBeforeIncomeTaxExpense	14,132	10,733	15,472
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	4,628	3,408	4,724	4,058
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Income Tax Expense	4,278	2,786	4,344
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Net Cash Flows, Total	9,854	7,947	11,128
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, 10 Percent Annual Discount for Estimated Timing of Cash Flows	(5,226)	(4,539)	(6,404)
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	4,628	3,408	4,724
Malaysia [Member]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Cash Inflows	1,245	1,754	2,751
Related Future [Abstract]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Production Costs	771	1,135	1,563
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs	148	82	161
DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesBeforeIncomeTaxExpense	326	537	1,027
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	303	416	692	557
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Income Tax Expense	0	66	210
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Net Cash Flows, Total	326	471	817
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, 10 Percent Annual Discount for Estimated Timing of Cash Flows	(23)	(55)	(125)
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	303	416	692
China [Member]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Cash Inflows	2,640	2,186	2,213
Related Future [Abstract]
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Production Costs	959	888	850
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Development Costs	143	202	228
DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesBeforeIncomeTaxExpense	1,538	1,096	1,135
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	902	612	565	139
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Income Tax Expense	316	239	268
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Net Cash Flows, Total	1,222	857	867
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, 10 Percent Annual Discount for Estimated Timing of Cash Flows	(320)	(245)	(302)
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves	$ 902	$ 612	$ 565