Condensed Consolidating Statements Of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	$ 1,029		$ 2,093
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	(6,915)		(5,924)
Proceeds from divestitures of proved and unproved properties	1,555		6,173
Additions to other property and equipment	(1,311)		(863)
Other investing activities	1,750		374
Cash used in investing activities	(4,921)		(240)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	10,104		8,343
Payments on credit facilities borrowings	(11,592)		(10,235)
Proceeds from issuance of term loans, net of discount and offering costs	3,789
Proceeds from issuance of senior notes, net of discount and offering costs	1,263		977
Cash paid to purchase debt			(2,032)
Proceeds from sales of noncontrolling interests	1,039
Other financing activities	(31)		1,101
Cash provided by (used in) financing activities	4,572		(1,846)
Change in cash and cash equivalents classified in current assets held for sale	(7)
Net increase (decrease) in cash and cash equivalents	673		7
Cash and cash equivalents, beginning of period	351		102
Cash and cash equivalents, end of period	1,024		109
Parent
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of term loans, net of discount and offering costs	3,789
Proceeds from issuance of senior notes, net of discount and offering costs	1,263		977
Cash paid to purchase debt			(2,032)
Other financing activities	(230)		(226)
Intercompany advances, net	(4,822)		1,281
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	997		2,078
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	(6,689)		(5,924)
Proceeds from divestitures of proved and unproved properties	1,555		6,173
Additions to other property and equipment	(936)		(472)
Other investing activities	2,845		8
Cash used in investing activities	(3,225)		(215)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	8,584		8,343
Payments on credit facilities borrowings	(10,304)		(10,235)
Proceeds from sales of noncontrolling interests	(10)
Other financing activities	61		1,323
Intercompany advances, net	4,807		(1,187)
Cash provided by (used in) financing activities	3,138		(1,756)
Net increase (decrease) in cash and cash equivalents	910		107
Cash and cash equivalents, beginning of period	1	[1]	2
Cash and cash equivalents, end of period	911		109
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	65		15
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	(226)
Additions to other property and equipment	(374)		(391)
Other investing activities	(172)
Cash used in investing activities	(772)		(391)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	1,520
Payments on credit facilities borrowings	(1,288)
Proceeds from sales of noncontrolling interests	1,049
Other financing activities	(818)		370
Intercompany advances, net	14		(94)
Cash provided by (used in) financing activities	477		276
Change in cash and cash equivalents classified in current assets held for sale	(7)
Net increase (decrease) in cash and cash equivalents	(237)		(100)
Cash and cash equivalents, beginning of period	350		100
Cash and cash equivalents, end of period	113
Eliminations
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	(33)
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to other property and equipment	(1)
Other investing activities	(923)		366
Cash used in investing activities	(924)		366
CASH FLOWS FROM FINANCING ACTIVITIES:
Other financing activities	956		(366)
Intercompany advances, net	1
Cash provided by (used in) financing activities	$ 957		$ (366)

[1] We have revised the amounts presented as long-term debt in the Guarantor Subsidiaries and Parent columns to properly reflect the long-term debt issued by the Parent of $8.2 billion, which was incorrectly presented as long-term debt attributable to the Guarantor Subsidiaries as of December 31, 2011. The impact of this error was not material to our December 31, 2011 financial statements.