Segment Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating expenses:
Depreciation, depletion and amortization	$ 903	$ 930	$ 955
Ceiling test impairment	0us-gaap_ImpairmentOfOilAndGasProperties	0us-gaap_ImpairmentOfOilAndGasProperties	1,488us-gaap_ImpairmentOfOilAndGasProperties
Allocated income tax (benefit)	382us-gaap_IncomeTaxExpenseBenefit	128us-gaap_IncomeTaxExpenseBenefit	(452)us-gaap_IncomeTaxExpenseBenefit
Commodity derivative income (expense)	(610)	97	(120)
Income (loss) before income taxes	1,032	201	(1,374)
Total assets	9,598us-gaap_Assets	9,321us-gaap_Assets
Additions to long-lived assets	2,200us-gaap_AdditionsToOtherAssetsAmount	2,106us-gaap_AdditionsToOtherAssetsAmount	1,742us-gaap_AdditionsToOtherAssetsAmount
Domestic [Member]
Segment Information [Line Items]
Oil, gas and NGL revenues	2,249	1,788	1,476
Operating expenses:
Lease operating	309	276	299
Gas Gathering, Transportation, Marketing and Processing Costs	174	137	107
Production and other taxes	105	67	67
Depreciation, depletion and amortization	857	668	683
General and administrative	221	219	211
Ceiling test impairment			1,488
Other	15	3	15
Allocated income tax (benefit)	210	155	(516)
Net income (loss) from oil and gas properties	358	263	(878)
Total assets	8,870	7,863	6,699
Additions to long-lived assets	2,044	1,932	1,655
Malaysia [Member]
Operating expenses:
Total assets		916	866
China [Member]
Segment Information [Line Items]
Oil, gas and NGL revenues	39	69	86
Operating expenses:
Lease operating	12	8	7
Gas Gathering, Transportation, Marketing and Processing Costs	0	0	0
Production and other taxes	6	12	18
Depreciation, depletion and amortization	13	17	21
General and administrative	1	0	0
Ceiling test impairment			0
Other	0	0	0
Allocated income tax (benefit)	5	19	24
Net income (loss) from oil and gas properties	2	13	16
Total assets	728	542	347
Additions to long-lived assets	156	174	87
Continuing Operations [Member]
Segment Information [Line Items]
Oil, gas and NGL revenues	2,288	1,857	1,562
Operating expenses:
Lease operating	321	284	306
Gas Gathering, Transportation, Marketing and Processing Costs	174	137	107
Production and other taxes	111	79	85
Depreciation, depletion and amortization	870	685	704
General and administrative	222	219	211
Ceiling test impairment			1,488
Other	15	3	15
Total operating expenses	1,713	1,407	2,916
Income (loss) from operations	575	450	(1,354)
Interest expenses, net of interest income, capitalized interest and other	(153)	(152)	(140)
Commodity derivative income (expense)	(610)	97	(120)
Income (loss) before income taxes	1,032	201	(1,374)
Total assets		$ 8,405	$ 7,046

Segment reporting net income (loss) from oil and gas properties.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Cost incurred related to the gas activities, such as transportation, marketing and processing crude oil, natural gas and refined petroleum products.

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The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced.

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