Supplementary Oil and Gas Disclosure (Unaudited) - Results of Operations of O&G Producing Activities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Results Of Operations Income Before Income Taxes Abstract
Revenues	$ 2,668	$ 2,560	$ 2,464
Production costs	390	400	353
Production taxes and other operating expenses	488	451	423
Depreciation, depletion and amortization	930	955	767
Impairment of oil and gas properties		1,488
Income taxes	304	(250)	325
Results of Operations, Oil and Gas Producing Activities Net Income (Excluding Corporate Overhead and Interest Costs), Total	556	(484)	596
Domestic [Member]
Results Of Operations Income Before Income Taxes Abstract
Revenues	1,777	1,469	1,735
Production costs	265	292	258
Production taxes and other operating expenses	204	174	161
Depreciation, depletion and amortization	668	683	622
Impairment of oil and gas properties		1,488
Income taxes	224	(410)	243
Results of Operations, Oil and Gas Producing Activities Net Income (Excluding Corporate Overhead and Interest Costs), Total	416	(758)	451
Malaysia [Member]
Results Of Operations Income Before Income Taxes Abstract
Revenues	822	1,005	647
Production costs	117	101	90
Production taxes and other operating expenses	272	259	242
Depreciation, depletion and amortization	244	251	126
Impairment of oil and gas properties		0
Income taxes	72	150	72
Results of Operations, Oil and Gas Producing Activities Net Income (Excluding Corporate Overhead and Interest Costs), Total	117	244	117
China [Member]
Results Of Operations Income Before Income Taxes Abstract
Revenues	69	86	82
Production costs	8	7	5
Production taxes and other operating expenses	12	18	20
Depreciation, depletion and amortization	18	21	19
Impairment of oil and gas properties		0
Income taxes	8	10	10
Results of Operations, Oil and Gas Producing Activities Net Income (Excluding Corporate Overhead and Interest Costs), Total	$ 23	$ 30	$ 28