Condensed Consolidating Statements Of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Parent	Sep. 30, 2011 Parent	Sep. 30, 2012 Guarantor Subsidiaries	Sep. 30, 2011 Guarantor Subsidiaries	Sep. 30, 2012 Non-Guarantor Subsidiaries	Sep. 30, 2011 Non-Guarantor Subsidiaries	Sep. 30, 2012 Eliminations	Sep. 30, 2011 Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash provided by operating activities	$ 1,978	$ 3,724	$ 0	$ 0	$ 1,814	$ 3,683	$ 164	$ 41	$ 0	$ 0
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments to Acquire Oil and Gas Property and Equipment	(10,338)	(9,118)	0	0	(9,891)	(9,118)	(447)	0	0	0
Proceeds from divestitures of proved and unproved properties	2,445	6,357	0	0	2,204	6,357	241	0	0	0
Additions to other property and equipment	(1,916)	(1,416)	0	0	(1,323)	(778)	(593)	(638)	0	0
Payments for (Proceeds from) Other Investing Activities	1,655	462	0	0	2,715	(130)	(246)	95	(814)	497
Cash used in investing activities	(8,154)	(3,715)	0	0	(6,295)	(3,669)	(1,045)	(543)	(814)	497
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	13,986	11,914	0	0	12,926	11,914	1,060	0	0	0
Payments on credit facilities borrowings	(13,614)	(12,057)	0	0	(12,862)	(12,057)	(752)	0	0	0
Proceeds from issuance of term loans, net of discount and offering costs	3,789	0	3,789		0		0		0
Proceeds from issuance of senior notes, net of discount and offering costs	1,263	977	1,263	977	0	0	0	0	0	0
Cash paid to purchase debt	0	(2,015)	0	(2,015)	0	0	0	0	0	0
Proceeds from sales of noncontrolling interests	1,056	0	0	0	0	0	1,056	0	0	0
Other	(499)	1,181	(367)	(393)	(178)	1,567	(768)	504	814	(497)
Intercompany advances, net	0	0	(4,685)	1,431	4,648	(1,438)	37	7	0	0
Cash provided by financing activities	5,981	0	0	0	4,534	(14)	633	511	814	(497)
Change in cash and cash equivalents classified in current assets held for sale	(14)	0	0	0	0	0	(14)	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	(209)	9	0	0	53	0	(262)	9	0	0
Cash and cash equivalents, beginning of period	351	102	0		1		350		0
Cash and cash equivalents, end of period	$ 142	$ 111	$ 0	$ 0	$ 54	$ 102	$ 88	$ 9	$ 0	$ 0