Condensed Consolidating Financial Information - Statements Of Cash Flows Table (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided By Operating Activities	$ 737	$ 2,643
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	(2,168)	(1,996)
Acquisitions of proved and unproved properties	(266)	(356)
Proceeds from divestitures of proved and unproved properties	14	248
Additions to other property and equipment	(93)	(620)
Other investing activities	0	(3)
Net Cash Used In Investing Activities	(2,512)	(1,780)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings	0	857
Payments on credit facilities borrowings	0	(1,239)
Proceeds from issuance of senior notes, net of discount and offering costs		3,460
Proceeds from issuance of oilfield services senior notes, net of discount and offering costs	0	394
Proceeds from issuance of oilfield services term loan, net of issuance costs	0	(3,362)
Other financing activities	(21)	0
Intercompany advances, net	0	0
Net Cash Used In Financing Activities	(282)	(238)
Net increase (decrease) in cash and cash equivalents	(2,057)	625
Cash and cash equivalents, beginning of period	4,108	837
Cash and cash equivalents, end of period	2,051	1,462
Parent Company Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided By Operating Activities	0	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	0	0
Acquisitions of 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
Payments on credit facilities borrowings		0
Proceeds from issuance of senior notes, net of discount and offering costs		2,966
Proceeds from issuance of oilfield services senior notes, net of discount and offering costs		0
Proceeds from issuance of oilfield services term loan, net of issuance costs		(3,362)
Other financing activities	(565)	(193)
Intercompany advances, net	(1,387)	1,186
Net Cash Used In Financing Activities	(1,952)	597
Net increase (decrease) in cash and cash equivalents	(1,952)	597
Cash and cash equivalents, beginning of period	4,100	799
Cash and cash equivalents, end of period	2,148	1,396
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided By Operating Activities	638	2,337
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	(2,077)	(1,946)
Acquisitions of proved and unproved properties	(266)	(354)
Proceeds from divestitures of proved and unproved properties	14	247
Additions to other property and equipment	(93)	(368)
Other investing activities	(2)	877
Net Cash Used In Investing Activities	(2,424)	(1,544)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings		140
Payments on credit facilities borrowings		(140)
Proceeds from issuance of senior notes, net of discount and offering costs		0
Proceeds from issuance of oilfield services senior notes, net of discount and offering costs		0
Proceeds from issuance of oilfield services term loan, net of issuance costs		0
Other financing activities	398	(29)
Intercompany advances, net	1,387	(764)
Net Cash Used In Financing Activities	1,785	(793)
Net increase (decrease) in cash and cash equivalents	(1)	0
Cash and cash equivalents, beginning of period	2	0
Cash and cash equivalents, end of period	1	0
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided By Operating Activities	99	306
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	(91)	(50)
Acquisitions of proved and unproved properties	0	(2)
Proceeds from divestitures of proved and unproved properties	0	1
Additions to other property and equipment	0	(252)
Other investing activities	3	60
Net Cash Used In Investing Activities	(88)	(243)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings		717
Payments on credit facilities borrowings		(1,099)
Proceeds from issuance of senior notes, net of discount and offering costs		494
Proceeds from issuance of oilfield services senior notes, net of discount and offering costs		394
Proceeds from issuance of oilfield services term loan, net of issuance costs		0
Other financing activities	(65)	(94)
Intercompany advances, net	0	(422)
Net Cash Used In Financing Activities	(65)	(10)
Net increase (decrease) in cash and cash equivalents	(54)	53
Cash and cash equivalents, beginning of period	84	38
Cash and cash equivalents, end of period	30	91
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided By Operating Activities	0	0
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	0	0
Acquisitions of 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	7
Net Cash Used In Investing Activities	0	7
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facilities borrowings		0
Payments on credit facilities borrowings		0
Proceeds from issuance of senior notes, net of discount and offering costs		0
Proceeds from issuance of oilfield services senior notes, net of discount and offering costs		0
Proceeds from issuance of oilfield services term loan, net of issuance costs		0
Other financing activities	(50)	(32)
Intercompany advances, net	0	0
Net Cash Used In Financing Activities	(50)	(32)
Net increase (decrease) in cash and cash equivalents	(50)	(25)
Cash and cash equivalents, beginning of period	(78)	0
Cash and cash equivalents, end of period	(128)	(25)
Consolidated Entities [Member]
CASH FLOWS FROM INVESTING ACTIVITIES:
Other investing activities	1	944
CASH FLOWS FROM FINANCING ACTIVITIES:
Other financing activities	$ (282)	$ (348)