Acquisitions and Divestitures (Detail) (USD $)	9 Months Ended						0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Chinese Subsidiary [Member] Oil and Gas Exploration and Production Reporting Segment [Member]	Sep. 30, 2014 Certain unproved properties in the Gulf of Mexico [Member] Oil and Gas Exploration and Production Reporting Segment [Member]	Sep. 30, 2014 Rovuma Offshore Area 1 in Mozambique [Member] Oil and Gas Exploration and Production Reporting Segment [Member]	Sep. 30, 2014 Pinedale/Jonah Assets [Member] Oil and Gas Exploration and Production Reporting Segment [Member]	Oct. 28, 2014 Gathering and processing assets in the Delaware basin [Member] Subsequent Event [Member] Western Gas Partners, LP [Member]
Property, Plant, and Equipment [Line Items]
Proceeds from divestitures	$ 4,770,000,000	$ 451,000,000	$ 1,075,000,000	$ 500,000,000	$ 2,640,000,000	$ 581,000,000
Net gains (losses) on divestitures	2,194,000,000	165,000,000	510,000,000	216,000,000	1,500,000,000
Working interest sold					10.00%
Purchase price							$ 1,500,000,000