Condensed Consolidating Statements Of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	$ 3,561	$ 1,978
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	(5,281)	(10,338)
Proceeds from divestitures of proved and unproved properties	2,789	2,445
Additions to other property and equipment	(639)	(1,916)
Other investing activities	1,084	1,655
Net Cash Used In Investing Activities	(2,047)	(8,154)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	7,136	13,986
Payments on credit facilities borrowings	(7,268)	(13,614)
Proceeds from issuance of senior notes, net of discount and offering costs	2,274	1,263
Proceeds from issuance of term loans, net of discount and offering costs	0	3,789
Cash paid to purchase debt	(2,116)	0
Proceeds from sales of noncontrolling interests	5	1,056
Other financing activities	(845)	(499)
Intercompany advances, net	0	0
Net Cash Provided By (Used In) Financing Activities	(814)	5,981
Change in cash and cash equivalents classified as current assets held for sale	0	(14)
Net increase (decrease) in cash and cash equivalents	700	(209)
Cash and cash equivalents, beginning of period	287	351
Cash and cash equivalents, end of period	987	142
Parent
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	0	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	0	0
Proceeds from divestitures of proved and unproved properties	0	0
Additions to other property and equipment	0	0
Other investing activities	0	0
Net Cash Used In Investing Activities	0	0
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	0	0
Payments on credit facilities borrowings	0	0
Proceeds from issuance of senior notes, net of discount and offering costs	2,274	1,263
Proceeds from issuance of term loans, net of discount and offering costs		3,789
Cash paid to purchase debt	(2,116)
Proceeds from sales of noncontrolling interests	0	0
Other financing activities	(374)	(367)
Intercompany advances, net	954	(4,618)
Net Cash Provided By (Used In) Financing Activities	738	67
Change in cash and cash equivalents classified as current assets held for sale		(7)
Net increase (decrease) in cash and cash equivalents	738	60
Cash and cash equivalents, beginning of period	228	1
Cash and cash equivalents, end of period	966	61
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	3,232	2,779
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	(4,642)	(10,208)
Proceeds from divestitures of proved and unproved properties	2,736	2,445
Additions to other property and equipment	(415)	(577)
Other investing activities	67	3,051
Net Cash Used In Investing Activities	(2,254)	(5,289)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	6,311	12,116
Payments on credit facilities borrowings	(6,310)	(12,051)
Proceeds from issuance of senior notes, net of discount and offering costs	0	0
Proceeds from issuance of term loans, net of discount and offering costs		0
Cash paid to purchase debt	0
Proceeds from sales of noncontrolling interests	5	0
Other financing activities	(297)	(154)
Intercompany advances, net	(687)	2,599
Net Cash Provided By (Used In) Financing Activities	(978)	2,510
Change in cash and cash equivalents classified as current assets held for sale		0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	362	200
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	(639)	(130)
Proceeds from divestitures of proved and unproved properties	53	0
Additions to other property and equipment	(224)	(1,339)
Other investing activities	757	(158)
Net Cash Used In Investing Activities	(53)	(1,627)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	825	1,870
Payments on credit facilities borrowings	(958)	(1,563)
Proceeds from issuance of senior notes, net of discount and offering costs	0	0
Proceeds from issuance of term loans, net of discount and offering costs		0
Cash paid to purchase debt	0
Proceeds from sales of noncontrolling interests	0	1,056
Other financing activities	46	(2,217)
Intercompany advances, net	(267)	2,019
Net Cash Provided By (Used In) Financing Activities	(354)	1,165
Change in cash and cash equivalents classified as current assets held for sale		(7)
Net increase (decrease) in cash and cash equivalents	(45)	(269)
Cash and cash equivalents, beginning of period	59	350
Cash and cash equivalents, end of period	14	81
Eliminations
Condensed Financial Statements, Captions [Line Items]
CASH FLOWS FROM OPERATING ACTIVITIES	(33)	(1,001)
CASH FLOWS FROM INVESTING ACTIVITIES:
Additions to proved and unproved properties	0	0
Proceeds from divestitures of proved and unproved properties	0	0
Additions to other property and equipment	0	0
Other investing activities	260	(1,238)
Net Cash Used In Investing Activities	260	(1,238)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	0	0
Payments on credit facilities borrowings	0	0
Proceeds from issuance of senior notes, net of discount and offering costs	0	0
Proceeds from issuance of term loans, net of discount and offering costs		0
Cash paid to purchase debt	0
Proceeds from sales of noncontrolling interests	0	0
Other financing activities	(220)	2,239
Intercompany advances, net	0	0
Net Cash Provided By (Used In) Financing Activities	(220)	2,239
Change in cash and cash equivalents classified as current assets held for sale		0
Net increase (decrease) in cash and cash equivalents	7	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$ 7	$ 0