Newfield Exploration (NFX) 10-Q 4 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	9 Months Ended
	Sep. 30, 2013	Oct. 31, 2013	Jun. 30, 2013
Document and Entity Information [Abstract]	'	'	'
Entity Registrant Name	'NEWFIELD EXPLORATION CO /DE/	'	'
Entity Central Index Key	'0000912750	'	'
Document Type	'10-Q	'	'
Document Period End Date	30-Sep-13	'	'
Amendment Flag	'false	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'Q3	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Public Float	'	'	$3,200,000,000
Entity Common Stock, Shares Outstanding	'	136,123,081	'

Consolidated_Balance_Sheet

Consolidated Balance Sheet (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$89	$88
Accounts receivable	441	452
Inventories	146	132
Derivative assets	29	125
Deferred Tax Assets, Net, Current	7	0
Other current assets	61	69
Total current assets	773	866
Property, Plant and Equipment, Gross	15,920	14,346
Less - accumulated depreciation, depletion and amortization	-8,110	-7,444
Total property and equipment, net	7,810	6,902
Derivative assets	31	17
Long-term investments	62	58
Deferred taxes	26	24
Other assets	41	45
Total assets	8,743	7,912
Current liabilities:	'	'
Accounts payable	87	69
Accrued liabilities	893	801
Advances from joint owners	41	31
Asset retirement obligations	6	10
Derivative liabilities	49	6
Deferred taxes	0	42
Total current liabilities	1,076	959
Other liabilities	42	47
Derivative liabilities	1	15
Long-term debt	3,485	3,045
Asset retirement obligations	144	132
Deferred taxes	1,076	934
Total long-term liabilities	4,748	4,173
Commitments and contingencies	0	0
Stockholders' equity:	'	'
Preferred stock ($0.01 par value, 5,000,000 shares authorized; no shares issued)	0	0
Common stock ($0.01 par value)	1	1
Additional paid-in capital	1,528	1,522
Treasury stock (at cost)	-16	-36
Accumulated other comprehensive loss	-4	-7
Retained earnings	1,410	1,300
Total stockholders' equity	2,919	2,780
Total liabilities and stockholders' equity	$8,743	$7,912

Consolidated_Balance_Sheet_Par

Consolidated Balance Sheet (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, except Share data, unless otherwise specified
ASSETS	'	'
Property and equipment, at cost, based on the full cost method of accounting for oil and gas properties	$1,666	$1,485
Stockholders' equity:	'	'
Preferred stock ($0.01 par value)	$0.01	$0.01
Preferred stock (5,000,000 shares authorized)	5,000,000	5,000,000
Preferred stock (no shares issued)	0	0
Common stock ($0.01 par value)	$0.01	$0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	136,671,131	136,530,907
Treasury Stock, shares	577,134	1,216,591

Consolidated_Statement_of_Oper

Consolidated Statement of Operations (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]	'	'	'	'
Income (Loss) from Continuing Operations, Per Basic Share	($0.03)	($0.61)	$0.57	$0.15
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share	$0.08	$0.37	$0.24	$1.47
Earnings (Loss) Per Share, Basic	$0.05	($0.24)	$0.81	$1.62
Income (Loss) from Continuing Operations, Per Diluted Share	($0.03)	($0.61)	$0.57	$0.15
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$0.08	$0.37	$0.24	$1.46
Earnings (Loss) Per Share, Diluted	$0.05	($0.24)	$0.81	$1.61
Operating expenses:	'	'	'	'
Depreciation, depletion and amortization	'	'	$664	$702
Income tax provision (benefit):	'	'	'	'
Current	-4	-9	-4	-4
Deferred	2	-37	51	18
Total income tax provision (benefit)	-2	-46	47	14
Income (Loss) from Continuing Operations Attributable to Parent	-4	-82	77	21
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	31	49	53	197
Net income (loss)	27	-33	130	218
Other income (expenses):	'	'	'	'
Interest expense	-52	-53	-153	-153
Capitalized interest	13	17	40	53
Commodity derivative income (expense)	-99	-98	-66	61
Other	1	-13	5	-15
Total other income (expenses)	-137	-147	-174	-54
Income (loss) before income taxes	-6	-128	124	35
Weighted-average number of shares outstanding for basic earnings (loss) per share	136	135	135	134
Weighted average number of shares outstanding for diluted earnings (loss) per share	136	135	136	135
Segment, Continuing Operations [Member]	'	'	'	'
Statement [Line Items]	'	'	'	'
Oil, gas and NGL revenues	486	371	1,291	1,124
Operating expenses:	'	'	'	'
Lease operating	104	100	299	305
Production and other taxes	19	17	52	53
Depreciation, depletion and amortization	171	172	482	510
General and administrative	61	57	160	161
Other	0	6	0	6
Total operating expenses	355	352	993	1,035
Income (loss) from operations	$131	$19	$298	$89

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Income (Loss) Attributable to Parent [Abstract]	'	'	'	'
Net income (loss)	$27	($33)	$130	$218
Other comprehensive income (loss):	'	'	'	'
Unrealized gain (loss) on investments, net of tax	0	0	3	2
Other Comprehensive Income (Loss), Net of Tax	0	0	3	2
Comprehensive income (loss)	$27	($33)	$133	$220

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
In Millions
BOP Stockholders' Equity Balance at Dec. 31, 2012	$2,780	$1	($36)	$1,522	$1,300	($7)
BOP Stockholders' Equity Balance, shares at Dec. 31, 2012	'	136.5	-1.2	'	'	'
Issuances of common stock, shares	'	0.2	'	'	'	'
Issuances of common stock, value	1	0	'	1	'	'
Stock-based compensation	32	'	'	32	'	'
Treasury stock, net, shares	'	'	0.6	'	'	'
Treasury stock, net value	-7	'	20	-27	'	'
Net income (loss)	130	'	'	'	130	'
Other Comprehensive Income (Loss), Net of Tax	3	'	'	'	'	3
Payments for Repurchase of Preferred Stock and Preference Stock	-20	'	'	'	-20	'
EOP Stockholders' Equity Balance at Sep. 30, 2013	$2,919	$1	($16)	$1,528	$1,410	($4)
EOP Stockholders' Equity Balance, shares at Sep. 30, 2013	'	136.7	-0.6	'	'	'

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'
Net income (loss)	$130	$218
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'
Depreciation, depletion and amortization	664	702
Deferred Income Tax Expense (Benefit), Continuing and Discontinuing Operations	89	5
Stock-based compensation	35	27
Commodity derivative income	66	-61
Cash receipts on derivative settlements, net	45	123
Other non-cash charges	7	11
Changes in operating assets and liabilities:	'	'
(Increase) decrease in accounts receivable	16	-43
(Increase) decrease in inventories	-4	-21
(Increase) decrease in other current assets	8	-21
(Increase) decrease in other assets	4	7
Increase (decrease) in accounts payable and accrued liabilities	30	-116
Increase (decrease) in advances from joint owners	10	-19
Increase (decrease) in other liabilities	-5	-8
Net cash provided by operating activities	1,095	804
Cash flows from investing activities:	'	'
Additions to oil and gas properties	-1,441	-1,279
Acquisitions of oil and gas properties	-64	-9
Proceeds from sales of oil and gas properties	25	382
Additions to furniture, fixtures and equipment	-25	-15
Redemptions of investments	1	0
Net cash used in investing activities	-1,504	-921
Cash flows from financing activities:	'	'
Proceeds from borrowings under credit arrangements	2,409	2,347
Repayments of borrowings under credit arrangements	-1,969	-2,288
Proceeds from issuance of senior notes	0	1,000
Debt issue costs	-4	-10
Repayment of senior subordinated notes	0	-875
Proceeds from issuances of common stock	1	1
Payments for Repurchase of Preferred Stock and Preference Stock	-20	0
Purchases of treasury stock, net	-7	-9
Net cash provided by (used in) financing activities	410	166
Increase (decrease) in cash and cash equivalents	1	49
Cash and cash equivalents, beginning of period	88	76
Cash and cash equivalents, end of period	$89	$125

Organization_and_Summary_of_Si

Organization and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Organization and Summary of Significant Accounting Policies	'
	Organization and Summary of Significant Accounting Policies:
	Organization and Principles of Consolidation
	We are an independent energy company engaged in the exploration, development and production of crude oil, natural gas and natural gas liquids (NGLs). Our principal domestic areas of operation include the Mid-Continent, the Rocky Mountains and the onshore Gulf Coast.
	Our consolidated financial statements include the accounts of Newfield Exploration Company, a Delaware corporation, and its subsidiaries. We proportionately consolidate our interests in oil and natural gas exploration and production ventures and partnerships in accordance with industry practice. All significant intercompany balances and transactions have been eliminated. Unless otherwise specified or the context otherwise requires, all references in these notes to “Newfield,” “we,” “us,” “our” or the “Company” are to Newfield Exploration Company and its subsidiaries.
	These unaudited consolidated financial statements reflect, in the opinion of our management, all adjustments, consisting only of normal and recurring adjustments, necessary to fairly state our financial position as of and results of operations for the periods presented. These financial statements have been prepared in accordance with the instructions to Form 10-Q and, therefore, do not include all disclosures required for financial statements prepared in conformity with accounting principles generally accepted in the United States of America. Interim period results are not necessarily indicative of results of operations or cash flows for a full year.
	These consolidated financial statements and notes should be read in conjunction with our audited consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2012.
	Discontinued Operations
	Following our decision to evaluate strategic alternatives for our businesses in Malaysia and China and the resulting assets-held-for-sale classification in the second quarter of 2013, the results of our international operations, which focus on offshore developments in Malaysia and China, are reflected separately as discontinued operations in the consolidated statement of operations on a line immediately after “Income (loss) from continuing operations.” See Note 3, “Discontinued Operations,” for additional disclosures. These financial statements and notes are inclusive of our international operations unless otherwise noted.
	Dependence on Commodity Prices
	As an independent oil and natural gas producer, our revenue, profitability and future rate of growth are substantially dependent on prevailing prices for oil, natural gas and NGLs. Historically, the energy markets have been very volatile, and there can be no assurance that commodity prices will not be subject to wide fluctuations in the future. A substantial or extended decline in commodity prices could have a material adverse effect on our financial position, results of operations, cash flows and access to capital and on the quantities of oil, natural gas and NGL reserves that we can economically produce.
	Use of Estimates
	The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires our management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, the reported amounts of revenues and expenses during the reporting period and the quantities and values of proved oil, natural gas and NGL reserves used in calculating depletion and assessing impairment of our oil and gas properties. Actual results could differ significantly from these estimates. Our most significant financial estimates are associated with our estimated proved oil, natural gas and NGL reserves and the fair value of our derivative positions.
	Investments
	Investments consist of debt and equity securities, as well as auction rate securities, a majority of which are classified as “available-for-sale” and stated at fair value. Accordingly, unrealized gains and losses and the related deferred income tax effects are excluded from earnings and reported as a separate component within the consolidated statement of comprehensive income. Realized gains or losses are computed based on specific identification of the securities sold. We regularly assess our investments for impairment and consider any impairment to be other than temporary if we intend to sell the security, it is more likely than not that we will be required to sell the security, or we do not expect to recover our cost of the security. We realized interest income and net gains on our investment securities of approximately $1 million for each of the three-month periods ended September 30, 2013 and 2012 and approximately $3 million and $2 million for each of the nine-month periods ended September 30, 2013 and 2012, respectively.
	Inventories
	Inventories primarily consist of tubular goods and well equipment held for use in our oil and natural gas operations and oil produced but not sold in our offshore operations in Malaysia and China. See Note 3, "Discontinued Operations" for details on our international crude oil inventory. Tubular goods and well equipment inventories are carried at the lower of cost or market.
	Oil and Gas Properties
	We use the full cost method of accounting for our oil and gas producing activities. Under this method, all costs incurred in the acquisition, exploration and development of oil and gas properties, including salaries, benefits and other internal costs directly attributable to these activities, are capitalized into cost centers that are established on a country-by-country basis. We capitalized approximately $35 million and $29 million of internal costs during the three-month periods ended September 30, 2013 and 2012, respectively, and approximately $108 million and $87 million during the nine-month periods ended September 30, 2013 and 2012, respectively. Interest expense related to unproved properties also is capitalized into oil and gas properties.
	Proceeds from the sale of oil and gas properties are applied to reduce the costs in the applicable cost center unless the reduction would significantly alter the relationship between capitalized costs and proved reserves, in which case a gain or loss is recognized.
	Capitalized costs and estimated future development costs are amortized using a unit-of-production method based on proved reserves associated with the applicable cost center. For each cost center, the net capitalized costs of oil and gas properties are limited to the lower of the unamortized cost or the cost center ceiling. A particular cost center ceiling is equal to the sum of:
	•	the present value (10% per annum discount rate) of estimated future net revenues from proved reserves using oil, natural gas and NGL reserve estimation requirements, which require use of the unweighted average first-day-of-the-month commodity prices for the prior 12 months, adjusted for market differentials (SEC pricing), applicable to our reserves (including the effects of hedging contracts that are designated for hedge accounting, if any); plus
	•	the cost of properties not included in the costs being amortized, if any; less
	•	related income tax effects.
	If net capitalized costs of oil and gas properties exceed the cost center ceiling, we are subject to a ceiling test writedown to the extent of such excess. If required, a ceiling test writedown reduces earnings and stockholders’ equity in the period of occurrence and, holding other factors constant, results in lower depreciation, depletion and amortization expense in future periods.
	The risk that we will be required to writedown the carrying value of our oil and gas properties increases when oil, natural gas and NGL prices decrease significantly for a prolonged period of time or if we have substantial downward revisions in our estimated proved reserves. At September 30, 2013, the ceiling value of our reserves was calculated based upon SEC pricing of $3.61 per MMBtu for natural gas and $95.15 per barrel of oil. Using these prices, the cost center ceiling with respect to our domestic full cost pool exceeded the net capitalized costs of the respective cost centers. As such, no ceiling test writedown was required at September 30, 2013. If there are declines in SEC pricing of oil and natural gas subsequent to September 30, 2013, we may be required to record a ceiling test writedown in future periods.
	At December 31, 2012, the ceiling value of our reserves was calculated based upon SEC pricing of $2.76 per MMBtu for natural gas and $94.84 per barrel of oil. Using these prices, the unamortized net capitalized costs of our domestic oil and gas properties exceeded the ceiling amount by, and caused a writedown of, approximately $1.5 billion ($948 million, after-tax).
	Other Property and Equipment
	Furniture, fixtures and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives, which range from three to seven years. Gathering systems and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives of 25 years.
	Segment Reporting
	Our continuing operations are comprised of a single business segment, the domestic exploration, development and production of oil and natural gas. Prior to classifying our international businesses as held-for-sale and discontinued operations, we reported business segments for Malaysia and China.
	Accounting for Asset Retirement Obligations
	The change in our asset retirement obligation (ARO) is set forth below (in millions):
	Balance at January 1, 2013	$	142
	Accretion expense	8
	Additions	6
	Revisions	2
	Settlements	(8		)
	Balance at September 30, 2013	150
	Less: Current portion of ARO at September 30, 2013	(6		)
	Total long-term ARO at September 30, 2013	$	144
	Derivative Financial Instruments
	Our derivative financial instruments are recorded on the consolidated balance sheet at fair value with changes in the derivative’s fair value recognized in current earnings. All of the derivative instruments that we utilize are to manage the price risk attributable to our expected oil and gas production. We have elected not to designate price-risk management activities as accounting hedges.
	The related cash flow impact of our derivative activities is reflected as cash flows from operating activities. See Note 5, “Derivative Financial Instruments,” for a more detailed discussion of our derivative activities.
	Offsetting Assets and Liabilities
	Our derivative financial instruments are subject to master netting arrangements and are reflected on our consolidated balance sheet accordingly. See Note 5, “Derivative Financial Instruments,” for details regarding the gross amounts, as well as the impact of our netting arrangements on our net derivative position. We only offset assets and liabilities in relation to our derivative financial instruments.
	New Accounting Requirements
	In December 2011, the FASB issued guidance regarding the disclosure of offsetting assets and liabilities. The guidance requires disclosure of both gross and net information about instruments and transactions eligible for offset arrangement. The guidance is effective for interim and annual periods beginning on or after January 1, 2013. We adopted the guidance in the quarter ended March 31, 2013. Adoption of the additional disclosures regarding offsetting assets and liabilities did not have a material impact on our financial position or results of operations.
	In February 2013, the FASB issued guidance regarding the reporting of amounts reclassified out of accumulated other comprehensive income. The guidance is effective for interim and annual periods beginning after December 15, 2012. We adopted the guidance in the quarter ended March 31, 2013. Adoption of the new reporting guidance did not have a material impact on our financial position or results of operations as we did not have reclassifications during the periods presented.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share Text Block	'
	Earnings Per Share:
	Basic earnings per share (EPS) is calculated by dividing net income, less any applicable adjustments, (the numerator) by the weighted-average number of shares of common stock (excluding unvested restricted stock and restricted stock units) outstanding during the period (the denominator). Diluted earnings per share incorporates the dilutive impact of outstanding stock options and unvested restricted stock and restricted stock units (using the treasury stock method). Under the treasury stock method, the amount the employee must pay for exercising stock options, the amount of unrecognized compensation expense related to unvested stock-based compensation grants and the amount of excess tax benefits that would be recorded when the award becomes deductible are assumed to be used to repurchase shares. See Note 11, “Stock-Based Compensation.”
	The following is the calculation of basic and diluted weighted-average shares outstanding and EPS for the indicated periods:
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(In millions, except per share data)
	Income (numerator):
	Income (loss) from continuing operations		$	(4	)	$	(82	)	$	77		$	21
	Income from discontinued operations, net of tax		31			49			53			197
	Net income (loss)		27			(33		)	130			218
	Repurchase of preferred shares of subsidiary(3)		(20		)	—			(20		)	—
	Net income (loss) attributable to common shareholders		$	7		$	(33	)	$	110		$	218
	Weighted-average shares (denominator):
	Weighted-average shares — basic		136			135			135			134
	Dilution effect of stock options and unvested restricted stock and restricted stock units outstanding at end of period(1) (2)		—			—			1			1
	Weighted-average shares — diluted		136			135			136			135
	Earnings per share:
	Basic:
	Income (loss) from continuing operations		$	(0.03	)	$	(0.61	)	$	0.57		$	0.15
	Income from discontinued operations before preferred share repurchase		0.23			0.37			0.39			1.47
	Repurchase of preferred shares of subsidiary(3)		(0.15		)	—			(0.15		)	—
	Income from discontinued operations		0.08			0.37			0.24			1.47
	Basic earnings (loss) per share		$	0.05		$	(0.24	)	$	0.81		$	1.62
	Diluted:
	Income (loss) from continuing operations		$	(0.03	)	$	(0.61	)	$	0.57		$	0.15
	Income from discontinued operations before preferred share repurchase		0.23			0.37			0.39			1.46
	Repurchase of preferred shares of subsidiary(3)		(0.15		)	—			(0.15		)	—
	Income from discontinued operations		0.08			0.37			0.24			1.46
	Diluted earnings (loss) per share		$	0.05		$	(0.24	)	$	0.81		$	1.61
	_______
	-1	The effect of unvested restricted stock or restricted stock units and stock options has not been included in the calculation of the shares outstanding for diluted EPS for the three months ended September 30, 2013 and 2012, as their effect would have been anti-dilutive. Had we recognized income from continuing operations for these periods, incremental shares attributable to the assumed vesting of unvested restricted stock and restricted stock units and the assumed exercise of outstanding stock options would have increased diluted weighted-average shares outstanding by 0.7 million and 0.6 million shares for the three months ended September 30, 2013 and 2012, respectively.
	-2	Excludes 4.1 million and 3.0 million shares of unvested restricted stock or restricted stock units and stock options for the nine-month periods ended September 30, 2013 and 2012, respectively, because including the effect would have been anti-dilutive.
	-3	The numerator includes an adjustment of $20 million related to the repurchase of preferred shares of a now wholly-owned subsidiary, which reduces net income (loss) for purposes of earnings per share for the three- and nine-month periods ended September 30, 2013. The subsidiary is part of our discontinued operations. See Note 15, "Related Party Transactions" for additional information.

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	'
	Discontinued Operations:
	In February 2013, we announced our decision to explore strategic alternatives for our international businesses. In accordance with specific accounting requirements, we met the criteria to classify our international businesses as held-for-sale and discontinued operations during the second quarter of 2013. As a result, the historical results of operations for our Malaysia and China businesses are reflected in our financial statements as “discontinued operations.”
	The following table summarizes the financial results of our discontinued operations for the following periods:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(In millions)
	Oil and gas revenues	$	189		$	245		$	659		$	797
	Operating expenses	128			158			501			472
	Income from discontinued operations	61			87			158			325
	Other income (expense)	(1		)	(3		)	(2		)	(3		)
	Income from discontinued operations before income taxes	60			84			156			322
	Income tax provision (benefit):
	Current	10			47			65			138
	Deferred	19			(12		)	38			(13		)
	Total income tax provision (benefit)	29			35			103			125
	Income from discontinued operations, net of tax	$	31		$	49		$	53		$	197
	Income Taxes
	The effective tax rates for our discontinued operations for the three months ended September 30, 2013 and 2012 were 48.2% and 40.8%, respectively. The effective tax rates for the nine months ended September 30, 2013 and 2012 were 65.7% and 38.5%, respectively. Historically, our international effective tax rate was approximately 37%. However, the effective tax rates for the three and nine months ended September 30, 2013 were affected by our fourth quarter 2012 decision to repatriate earnings from our foreign operations, which resulted in earnings and profits of our international businesses being taxed both in the U.S. and the local country. In determining our tax provision for the year ended December 31, 2012, we used estimates of taxable income for the various tax jurisdictions. These estimates are not finalized until we file our tax return in the following year. During the third quarter of 2013, we filed our 2012 tax return which resulted in a return to provision true-up of $16 million.
	A summary of assets and liabilities included in our consolidated balance sheet attributable to discontinued operations follows:
		September 30,			December 31,
		2013			2012
		(In millions)
	Current assets:
	Cash and cash equivalents	$	69		$	76
	Accounts receivable	144			207
	Inventories	113			91
	Other current assets	27			31
	Total current assets	353			405
	Noncurrent assets:
	Oil and gas properties, net of accumulated depreciation, depletion and amortization of $1,032 and $843 as of September 30, 2013 and December 31, 2012, respectively	882			781
	Deferred taxes	27			24
	Other assets	4			4
	Total noncurrent assets	913			809
	Total assets	$	1,266		$	1,214
	Current liabilities:
	Accounts payable	$	41		$	50
	Accrued liabilities	285			269
	Other current liabilities	17			21
	Total current liabilities	343			340
	Noncurrent liabilities:
	Asset retirement obligations	41			38
	Deferred taxes	82			41
	Other liabilities	14			23
	Total noncurrent liabilities	137			102
	Total liabilities	$	480		$	442
	Crude Oil Inventories
	Substantially all of the crude oil from our offshore operations in Malaysia and China is produced into floating production, storage and off-loading vessels (FPSOs) or onshore storage terminals and “lifted” and sold periodically as barge quantities are accumulated. The product inventory from our international operations consisted of approximately 990,000 barrels and 744,000 barrels of crude oil valued at cost of $79 million and $64 million at September 30, 2013 and December 31, 2012, respectively, and are included in the "Inventories" line item in the preceding table and our consolidated balance sheet. Cost for purposes of the carrying value of oil inventory is the sum of production costs and depletion expense.
	Oil and Gas Properties
	At September 30, 2013, the oil and gas properties associated with our discontinued operations included $115 million not subject to amortization, comprised of $45 million incurred prior to 2011, $2 million incurred in 2011, $24 million incurred in 2012 and $44 million incurred in 2013. The cost center ceilings with respect to our Malaysia and China full cost pools exceeded the net capitalized costs of the respective cost centers at December 31, 2012 and September 30, 2013, and as such, no ceiling test writedowns were required.

Oil_and_Gas_Assets

Oil and Gas Assets	9 Months Ended
	Sep. 30, 2013
Oil and Gas Property [Abstract]	'
Oil and Gas Assets Text Block	'
	Oil and Gas Assets:
	Property and Equipment
	Property and equipment consisted of the following:
		September 30,			December 31,
		2013			2012
		(In millions)
	Oil and gas properties:
	Subject to amortization	$	14,019		$	12,647
	Not subject to amortization	1,666			1,485
	Gross oil and gas properties	15,685			14,132
	Accumulated depreciation, depletion and amortization	(8,035		)	(7,378		)
	Net oil and gas properties	7,650			6,754
	Other property and equipment:
	Furniture, fixtures and equipment	143			141
	Gathering systems and equipment	92			73
	Accumulated depreciation and amortization	(75		)	(66		)
	Net other property and equipment	160			148
	Total property and equipment, net	$	7,810		$	6,902
	The following is a summary of our oil and gas properties not subject to amortization as of September 30, 2013. At September 30, 2013, approximately 86% of our oil and gas properties not subject to amortization were associated with unconventional resource plays. Because of the size of our unconventional resource plays, the entire evaluation can take significantly longer than four years. However, we believe that our evaluation activities related to substantially all of our conventional properties not subject to amortization will be completed within four years.
		Costs Incurred In
		2013			2012			2011		2010 and Prior		Total
		(In millions)
	Acquisition costs	$	116		$	112		$	252	$	355	$	835
	Exploration costs	491			28			13		36		568
	Development costs	1			31			39		—		71
	Fee mineral interests	—			—			—		23		23
	Capitalized interest	40			67			62		—		169
	Total oil and gas properties not subject to amortization	$	648		$	238		$	366	$	414	$	1,666
	Gulf of Mexico Asset Sale
	In October 2012, we closed on the sale of our remaining assets in the Gulf of Mexico to W&T Offshore, Inc. for approximately $208 million, subject to customary post-closing adjustments. The sale of our remaining assets in the Gulf of Mexico did not significantly alter the relationship between capitalized costs and proved reserves, and as such, all proceeds were recorded as adjustments to our domestic full cost pool with no gain or loss recognized. These consolidated financial statements include the results of our Gulf of Mexico operations through the date of sale.
	Other Asset Sales
	During the nine months ended September 30, 2013 and the year ended December 31, 2012, we sold certain oil and gas properties for proceeds of approximately $25 million and $630 million (includes Gulf of Mexico asset sale discussed above), respectively. The cash flows and results of operations for the assets included in a sale are included in our consolidated financial statements up to the date of sale. All of the proceeds associated with our asset sales were recorded as adjustments to our domestic full cost pool.

Derivative_Financial_Instrumen

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedges, Assets [Abstract]	'
Derivative Financial Instruments Text Block	'
	Derivative Financial Instruments:
	Commodity Derivative Instruments
	We utilize the following derivative strategies, which consist of either a single derivative instrument or a combination of instruments, to hedge against the variability in cash flows associated with the forecasted sale of our future oil and natural gas production domestically.
	•	Fixed-price swaps. With respect to a swap position, the counterparty is required to make a payment to us if the settlement price for any settlement period is less than the swap strike price, and we are required to make a payment to the counterparty if the settlement price for any settlement period is greater than the swap strike price.
	•	Collars (combination of purchased put options (floor) and sold call options (ceiling)). For a collar position, the counterparty is required to make a payment to us if the settlement price for any settlement period is below the floor strike price while we are required to make payment to the counterparty if the settlement price for any settlement period is above the ceiling strike price. Neither party is required to make a payment to the other party if the settlement price for any settlement period is equal to or greater than the floor strike price and equal to or less than the ceiling strike price.
	•	Fixed-price swaps with sold puts. A swap with a sold put position consists of a standard swap position plus a put sold by us with a strike price below the associated fixed-price swap. This structure enables us to increase the fixed-price swap with the value received through the sale of the put. If the settlement price for any settlement period falls equal to or below the put strike price, then we will only receive the difference between the swap price and the put strike price. If the settlement price is greater than the put strike price, the result is the same as it would have been with a standard swap only.
	•	Collars with sold puts. A collar with a sold put position consists of a standard collar position plus a put sold by us with a strike price below the floor strike price of the collar. This structure enables us to improve the collar strike prices with the value received through the sale of the additional put. If the settlement price for any settlement period falls equal to or below the additional put strike price, then we will receive the difference between the floor strike price and the additional put strike price. If the settlement price is greater than the additional put strike price, the result is the same as it would have been with a standard collar only.
	•	Swaptions. A swaption is an option to exercise a swap where the buyer (counterparty) of the swaption purchases (by payment of premium to the seller (Newfield)) the right, but not the obligation to, enter into a fixed-price swap with the seller on a predetermined date (expiration date). The swap price is a fixed price determined at the time of the swaption contract.  If the swaption is exercised, the contract will become a swap treated the same as described above.
	While the use of these derivative instruments limits the downside risk of adverse commodity price movements, their use also may limit future income from favorable commodity price movements.
	Our oil and gas derivative contracts are settled based upon reported prices on the NYMEX. The estimated fair value of these contracts is based upon various factors, including closing exchange prices on the NYMEX, over-the-counter quotations, estimated volatility, non-performance risk adjustments using credit default swaps and time to maturity. The calculation of the fair value of collars, sold puts and swaptions requires the use of an option-pricing model. See Note 8, “Fair Value Measurements.”
	At September 30, 2013, we had outstanding positions with respect to our future production as set forth in the tables below.
	Natural Gas
						NYMEX Contract Price Per MMBtu
														Collars								Estimated Fair Value Asset (Liability)
	Period and Type of Instrument		Volume in MMMBtus			Swaps (Weighted Average)				Sold Puts (Weighted Average)				Floors (Weighted Average)				Ceilings (Weighted Average)
																						(In millions)
	2013:00:00
	Fixed-price swaps		13,800			$	4.09			—				—				—				$	7
	Collars with sold puts(A)		6,770			3.44				$	3.82			$	5.24			$	6.2			7
	Collars with sold puts		4,575			—				3				3.75				4.75				1
	2014:00:00
	Fixed-price swaps		85,775			3.98				—				—				—				10
	Collars		23,725			—				—				3.75				4.62				4
	2015:00:00
	Fixed-price swaps		49,275			4.28				—				—				—				11
	Collars		38,325			—				—				3.93				4.74				6
	Total																					$	46
	________
	(A)	During the first quarter of 2012, natural gas spot market prices were below the puts we sold on our collar with sold put positions for April through December 2012 and the full-year 2013, exposing us further to the softening natural gas spot market. As a result, during the first quarter of 2012, we entered into additional swap positions in the over-the-counter market that effectively prevented any further erosion in the value of our natural gas collar with sold put positions. The new swap positions added during the first quarter of 2012 were for the same volumes as our full-year 2013 collar with sold put positions. The economics from the combination of these additional swap positions and our natural gas collar with sold put positions will result in an effective average fixed price of $4.86 per MMBtu as long as natural gas spot prices for the respective time periods settle below the puts we sold on our collar with sold put positions. In the event natural gas spot prices settle above the ceilings on our associated collar with sold put positions, we would not recover the difference through the sale of our production as we would realize losses on both instruments discussed above.
	Crude Oil
						NYMEX Contract Price Per Bbl
														Collars								Estimated Fair Value
	Period and Type of Instrument		Volume in MBbls			Swaps				Sold Puts				Floors				Ceilings				Asset (Liability)
						(Weighted Average)				(Weighted Average)				(Weighted Average)				(Weighted Average)
																						(In millions)
	2013:00:00
	Fixed-price swaps		213			$	91.1			—				—				—				$	(2	)
	Fixed-price swaps with sold puts		920			97.49				$	75			—				—				(4		)
	Collars with sold puts		2,546			—				80				$	95			$	115.59			—
	2014:00:00
	Fixed-price swaps		7,127			89.89				—				—				—				(36		)
	Fixed-price swaps with sold puts		5,840			95.16				75				—				—				(4		)
	Collars with sold puts		2,190			—				75.83				90.83				102.93				(2		)
	2015:00:00
	Fixed-price swaps		6,567			90.39				—				—				—				12
	Fixed-price swaps with sold puts		3,107			90.04				66.53												3
	Swaptions(A)		—			90				—				—				—				(3		)
	Total																					$	(36	)
	________
	(A)	During the third quarter of 2013, we sold crude oil swaption contracts that would potentially hedge 1,460 MBbls of calendar year 2015 production if exercised on their expiration date in the fourth quarter of 2013. These contracts give the counterparties the option to enter into swap contracts with us at $90.00/Bbl for calendar year 2015. We received premiums of $3 million upon execution of these contracts, which were recorded in current "Derivative liabilities" on our consolidated balance sheet.
	Additional Disclosures about Derivative Instruments and Hedging Activities
	We had derivative financial instruments recorded in our consolidated balance sheet as assets (liabilities) at their respective estimated fair value, as set forth below.
			Derivative Assets																Derivative Liabilities
			Gross Fair Value				Offset in Balance Sheet				Balance Sheet Location								Gross Fair Value				Offset in Balance Sheet		Balance Sheet Location
											Current				Noncurrent										Current			Noncurrent
	September 30, 2013		(In millions)																(In millions)
	Natural gas positions		$	51			$	(4	)		$	29			$	18			$	(5	)		$	4	$	(1	)	$	—
	Oil positions		23				(10		)		—				13				(59		)		10		(48		)	(1		)
	Total		$	74			$	(14	)		$	29			$	31			$	(64	)		$	14	$	(49	)	$	(1	)
	December 31, 2012
	Natural gas positions		$	86			$	(5	)		$	79			$	2			$	(16	)		$	5	$	(4	)	$	(7	)
	Oil positions		77				(16		)		46				15				(26		)		16		(2		)	(8		)
	Total		$	163			$	(21	)		$	125			$	17			$	(42	)		$	21	$	(6	)	$	(15	)
The amount of gain (loss) recognized in “Commodity derivative income (expense)” in our consolidated statement of operations related to our derivative financial instruments was as follows:
		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013				2012				2013				2012
		(In millions)
Derivatives not designated as hedging instruments:
Realized gain (loss) on natural gas positions		$	19			$	37			$	51			$	135
Realized gain (loss) on oil positions		(12		)		3				(9		)		(4		)
Realized gain (loss) on basis positions		—				(3		)		—				(8		)
Total realized gain(1)		7				37				42				123
Unrealized gain (loss) on natural gas positions		(6		)		(79		)		(24		)		(162		)
Unrealized gain (loss) on oil positions		(100		)		(59		)		(84		)		92
Unrealized gain (loss) on basis positions		—				3				—				8
Total unrealized loss		(106		)		(135		)		(108		)		(62		)
Total		$	(99	)		$	(98	)		$	(66	)		$	61
________
-1	The total realized gain on commodity derivatives may differ from the cash receipts on derivative settlements as a result of the receipt or payment of premiums, or due to the recognition of premiums previously received associated with derivatives settled during the period.
The use of derivative transactions involves the risk that the counterparties will be unable to meet the financial terms of such transactions. Our derivative contracts are with multiple counterparties to minimize our exposure to any individual counterparty, and we have netting arrangements with all of our counterparties that provide for offsetting payables against receivables from separate derivative instruments with that counterparty. At September 30, 2013, nine of our 15 counterparties accounted for approximately 85% of our estimated future hedged production, with no single counterparty accounting for more than 15% of that production.
A portion of our derivative instruments are with lenders under our credit facility. Our credit facility, senior notes, senior subordinated notes and substantially all of our derivative instruments contain provisions that provide for cross defaults and acceleration of those debt and derivative instruments in certain situations.

Accounts_Receivable

Accounts Receivable	9 Months Ended
	Sep. 30, 2013
Accounts Receivable, Net, Current [Abstract]	'
Accounts Receivable Text Block	'
	Accounts Receivable:
	Accounts receivable consisted of the following:
		September 30,		December 31,
		2013		2012
		(In millions)
	Revenue	$	249	$	291
	Joint interest	173		154
	Other	19		8
	Reserve for doubtful accounts	—		(1		)
	Total accounts receivable	$	441	$	452

Accrued_Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2013
Accrued Liabilities, Current [Abstract]	'
Accrued Liabilities Text Block	'
	Accrued Liabilities:
	Accrued liabilities consisted of the following:
		September 30,		December 31,
		2013		2012
		(In millions)
	Revenue payable	$	158	$	95
	Accrued capital costs	435		355
	Accrued lease operating expenses	64		95
	Employee incentive expense	39		50
	Accrued interest on debt	46		43
	Taxes payable	97		108
	Other	54		55
	Total accrued liabilities	$	893	$	801

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements Text Block	'
	Fair Value Measurements:
	Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The authoritative guidance requires disclosure of the framework for measuring fair value and requires that fair value measurements be classified and disclosed in one of the following categories:
	Level 1:	Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. We consider active markets as those in which transactions for the assets or liabilities occur with sufficient frequency and volume to provide pricing information on an ongoing basis.
	Level 2:	Quoted prices in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability. This category includes those derivative instruments that we value using observable market data. Substantially all of these inputs are observable in the marketplace throughout the full term of the derivative instrument, can be derived from observable data or supported by observable levels at which transactions are executed in the marketplace. Instruments in this category include non-exchange traded derivatives such as over-the-counter commodity fixed-price swaps and certain investments.
	Level 3:	Measured based on prices or valuation models that require inputs that are both significant to the fair value measurement and less observable from objective sources (i.e., supported by little or no market activity). Level 3 instruments primarily include derivative instruments, such as commodity options (price collars, sold puts and swaptions) and other financial investments.
	•	Our valuation models for derivative contracts are primarily industry-standard models (i.e., Black-Scholes) that consider various inputs including: (a) quoted forward prices for commodities, (b) time value, (c) volatility factors, (d) counterparty credit risk and (e) current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Although we utilize third-party broker quotes to assess the reasonableness of our prices and valuation techniques for derivative instruments, we do not have sufficient corroborating market evidence to support classifying these assets and liabilities as Level 2.
	•	Our valuation methodology for investments is a discounted cash flow model that considers various inputs including: (a) the coupon rate specified under the debt instruments, (b) the current credit ratings of the underlying issuers, (c) collateral characteristics and (d) risk-adjusted discount rates.
	•	Our valuation model for the Stockholder Value Appreciation Program (SVAP) is a Monte Carlo simulation that is based on a probability model and considers various inputs including: (a) the measurement date stock price, (b) time value and (c) historical and implied volatility. See Note 11, "Stock-Based Compensation," for a description of the SVAP.
	Financial assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of the fair value of assets and liabilities and their placement within the fair value hierarchy levels.
	Fair Value of Financial Instruments
	The following table summarizes the valuation of our financial assets (liabilities) of our continuing operations by measurement levels:
			Fair Value Measurement Classification
			Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)			Total
			(In millions)
	As of December 31, 2012:
	Money market fund investments		$	22		$	—		$	—		$	22
	Deferred compensation plan assets		6			—			—			6
	Investments available-for-sale:
	Equity securities		7			—			—			7
	Auction rate securities		—			—			36			36
	Oil and gas derivative swap contracts		—			6			—			6
	Oil and gas derivative option contracts		—			—			115			115
	Stock-based compensation liability awards		(2		)	—			—			(2		)
	Total		$	33		$	6		$	151		$	190
	As of September 30, 2013:
	Money market fund investments		$	11		$	—		$	—		$	11
	Deferred compensation plan assets		8			—			—			8
	Investments available-for-sale:
	Equity securities		7			—			—			7
	Auction rate securities		—			—			39			39
	Oil and gas derivative option contracts		—			—			10			10
	Stock-based compensation liability awards		(7		)	—			(8		)	(15		)
	Total		$	19		$	—		$	41		$	60
	The determination of the fair values above incorporates various factors, which include the impact of our non-performance risk on our liabilities, the credit standing of the counterparties involved and the impact of credit enhancements (such as cash deposits, letters of credit and priority interests), if any. We utilize credit default swap values to assess the impact of non-performance risk when evaluating both our liabilities to and receivables from counterparties.
	As of September 30, 2013, we held $39 million of auction rate securities maturing beginning in 2033 that are classified as a Level 3 fair value measurement. This amount reflects a decrease in the fair value of these investments since the time of purchase of $6 million ($4 million net of tax) recorded under the caption “Accumulated other comprehensive loss” on our consolidated balance sheet. As of December 31, 2012, we held $36 million of auction rate securities, which reflected a decrease in the fair value of $9 million ($6 million net of tax) since the date of purchase. The debt instruments underlying our auction rate securities are mostly investment grade (rated BBB or better) and are guaranteed by the United States government or backed by private loan collateral. We do not believe the decrease in the fair value of these securities is permanent because we currently intend to hold these investments until the auction succeeds, the issuer calls the securities or the securities mature. Our current available borrowing capacity under our credit arrangements provides us the liquidity to continue to hold these securities.
	The following table sets forth a reconciliation of changes in the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy for the indicated periods:
			Investments			Derivatives			Stock-based Compensation			Total
			(In millions)
	Balance at January 1, 2012		$	32		$	71		$	—		$	103
	Total realized or unrealized gains (losses):
	Included in earnings		—			100			—			100
	Included in other comprehensive income (loss)		2			—			—			2
	Purchases, issuances and settlements:
	Settlements		—			(69		)	—			(69		)
	Transfers in and out of Level 3		—			—			—			—
	Balance at September 30, 2012		$	34		$	102		$	—		$	136
	Change in unrealized gains or losses included in earnings relating to Level 3 instruments still held at September 30, 2012		$	—		$	67		$	—		$	67
	Balance at January 1, 2013		$	36		$	115		$	—		$	151
	Total realized or unrealized gains (losses):
	Included in earnings		—			(59		)	(8		)	(67		)
	Included in other comprehensive income (loss)		4			—			—			4
	Purchases, issuances and settlements:
	Settlements		(1		)	(46		)	—			(47		)
	Transfers in and out of Level 3		—			—			—			—
	Balance at September 30, 2013		$	39		$	10		$	(8	)	$	41
	Change in unrealized gains or losses included in earnings relating to Level 3 instruments still held at September 30, 2013		$	—		$	(8	)	$	(8	)	$	(16	)
	Qualitative Disclosures about Unobservable Inputs for Level 3 Fair Value Measurements
	Investments. We utilize a discounted cash flow model in the determination of the valuation of our auction rate securities classified as Level 3. This model considers various inputs including (a) the coupon rate specified under the debt instrument, (b) the current credit rating of the underlying issuers, (c) collateral characteristics and (d) risk-adjusted discount rates. The most significant unobservable factor in determining the fair value of these investments, is market liquidity. A significant change in the liquidity of the market for auction rate securities would lead to a corresponding change in the fair value measurement of these investments.
	Derivatives. Our valuation models for Level 3 derivative contracts are primarily industry-standard models that consider various factors, including certain significant unobservable inputs such as (a) quoted forward prices for commodities, (b) volatility factors and (c) counterparty credit risk. The calculation of the fair value of our option contracts requires the use of an option-pricing model. The estimated future prices are compared to the strike prices fixed by the hedge agreements, and the resulting estimated future cash inflows or outflows over the lives of the hedges are discounted to calculate the fair value of the derivative contracts. These pricing and discounting variables are sensitive to market volatility as well as changes in future price forecasts, regional price differences and interest rates. Significant increases (decreases) in the quoted forward prices for commodities generally lead to corresponding decreases (increases) in the fair value measurement of our oil and gas derivative contracts. Significant changes in the volatility factors utilized in our option-pricing model can cause significant changes in the fair value measurement of our oil and gas derivative contracts.
	The determination of the fair values of derivative instruments incorporates various factors that include not only the impact of our non-performance risk on our liabilities but also the credit standing of the counterparties involved and the impact of credit enhancements (such as cash deposits, letters of credit and priority interests). Historically, we have not experienced significant changes in the fair value of our derivative contracts resulting from changes in counterparty credit risk as the counterparties for all of our hedging transactions have an “investment grade” credit rating.
	Stock-Based Compensation. The Level 3 component of stock-based compensation is comprised of the SVAP implemented in September 2013. For additional details regarding the SVAP, see Note 11, "Stock-Based Compensation." Our valuation model for the SVAP considers various factors, including certain unobservable inputs such as volatility factors. The calculation of the fair value of the SVAP liability requires the use of a probability-based Monte Carlo simulation in a risk-neutral framework. The simulation predicts multiple scenarios of future stock return over the performance period, which are discounted to calculate the fair value. The fair value is recognized over a service period derived from the simulation. Future stock returns and discounting variables are sensitive to market volatility. Significant increases (decreases) in the volatility factors utilized in our option-pricing model can cause significant increases (decreases) in the fair value measurement of the SVAP liability.
	Quantitative Disclosures about Unobservable Inputs for Level 3 Fair Value Measurements
			Estimated Fair Value Asset (Liability)			Quantitative Information about Level 3 Fair Value Measurements
Instrument Type		Valuation Technique					Unobservable Input	Range
		(In millions)
Oil option contracts		$	(10	)	Option model		NYMEX oil price forward curve	$	87.07		—		$	104.67
							Oil price volatility curves	15.48		%	—		26.34		%
							Credit risk	0.01		%	—		1.64		%
Natural gas option contracts		$	20		Option model		NYMEX natural gas price forward curve	$	3.49		—		$	4.26
							Natural gas price volatility curves	20.47		%	—		32.03		%
							Credit risk	0.01		%	—		2.19		%
SVAP		$	(8	)	Monte Carlo		Historical volatility						44.7		%
							Implied volatility	37.1		%	—		39.8		%
The underlying inputs in the determination of the valuation of our auction rate securities are developed by a third party and, therefore, not included in the quantitative analysis above.
Fair Value of Debt
The estimated fair value of our notes, based on quoted prices in active markets (Level 1) as of the indicated dates, was as follows:
		September 30,			December 31,
		2013			2012
		(In millions)
5¾% Senior Notes due 2022		$	768		$	836
5⅝% Senior Notes due 2024		970			1,074
7⅛% Senior Subordinated Notes due 2018		623			630
6⅞% Senior Subordinated Notes due 2020		737			749

Debt

Debt	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Debt Text Block	'
	Debt:
	As of the indicated dates, our debt consisted of the following:
		September 30,			December 31,
		2013			2012
		(In millions)
	Senior unsecured debt:
	Revolving credit facility - LIBOR based loans	$	440		$	—
	Total credit arrangements	440			—
	5¾% Senior Notes due 2022	750			750
	5⅝% Senior Notes due 2024	1,000			1,000
	Total senior unsecured debt	2,190			1,750
	7⅛% Senior Subordinated Notes due 2018	600			600
	6⅞% Senior Subordinated Notes due 2020	700			700
	Discount on notes	(5		)	(5		)
	Total long-term debt	$	3,485		$	3,045
	Credit Arrangements
	In April 2013, we entered into the second amendment to the credit facility, which allows the sale of the Company's international businesses pursuant to certain terms and conditions. In June 2013, we entered into the third amendment of our Credit Agreement. This amendment extended the maturity date of the revolving credit facility from June 2016 to June 2018 and increased the borrowing capacity from $1.25 billion to $1.4 billion. We incurred $4 million of deferred financing costs related to this amendment. As of September 30, 2013, the largest individual loan commitment by any lender was 14% of total commitments.
	Loans under the credit facility bear interest, at our option, equal to (a) a rate per annum equal to the higher of the prime rate announced from time to time by JPMorgan Chase Bank, N.A. or the weighted average of the rates on overnight federal funds transactions with members of the Federal Reserve System during the last preceding business day plus 50 basis points, plus a margin that is based on a grid of our debt rating (75 basis points per annum at September 30, 2013) or (b) the London Interbank Offered Rate, plus a margin that is based on a grid of our debt rating (175 basis points per annum at September 30, 2013).
	Under our credit facility, we pay commitment fees on available but undrawn amounts based on a grid of our debt rating (30 basis points per annum at September 30, 2013). We incurred aggregate commitment fees under our current credit facility of approximately $0.8 million and $2.5 million for the three and nine months ended September 30, 2013, respectively, which are recorded in “Interest expense” on our consolidated statement of operations. For the three and nine months ended September 30, 2012, we incurred commitment fees under our current and previous credit facilities of approximately $0.9 million and $2.5 million, respectively.
	Our credit facility has restrictive financial covenants that include the maintenance of a ratio of total debt to book capitalization not to exceed 0.6 to 1.0 and maintenance of a ratio of earnings before gain or loss on the disposition of assets, interest expense, income taxes and noncash items (such as depreciation, depletion and amortization expense, unrealized gains and losses on commodity derivatives, ceiling test writedowns and goodwill impairments) to interest expense of at least 3.0 to 1.0. At September 30, 2013, we were in compliance with all of our debt covenants.
	As of September 30, 2013, we had $70 million of undrawn letters of credit outstanding related to our business in Malaysia under our credit facility. Letters of credit are subject to a fronting fee of 20 basis points and annual fees based on a grid of our debt rating (175 basis points at September 30, 2013). Additionally, as of September 30, 2013, we had $1 million of other undrawn letters of credit outstanding.
	Subject to compliance with the restrictive covenants in our credit facility, at September 30, 2013, we had a total of $195 million of available borrowing capacity under our money market lines of credit with various financial institutions, the availability of which is at the discretion of the financial institutions.
	The credit facility includes events of default relating to customary matters, including, among other things, nonpayment of principal, interest or other amounts; violation of covenants; inaccuracy of representations and warranties in any material respect; a change of control; or certain other material adverse changes in our business. Our senior notes and senior subordinated notes also contain standard events of default. If any of the foregoing defaults were to occur, our lenders under the credit facility could terminate future lending commitments, and our lenders under both the credit facility and our notes could declare the outstanding borrowings due and payable. In addition, our credit facility, senior notes, senior subordinated notes and substantially all of our hedging arrangements contain provisions that provide for cross defaults and acceleration of those debt and hedging instruments in certain situations.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes Text Block	'
	Income Taxes:
	The provision for income taxes for continuing operations for the indicated periods was different than the amount computed using the federal statutory rate (35%) for the following reasons:
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013		2012
		(In millions)
	Amount computed using the statutory rate	$	(3	)	$	(45	)	$	43	$	12
	Increase (decrease) in taxes resulting from:
	State and local income taxes, net of federal effect	1			(1		)	4		2
	Total provision (benefit) for income taxes	$	(2	)	$	(46	)	$	47	$	14
	The effective tax rates for continuing operations for the three months ended September 30, 2013 and 2012 were 32.9% and 35.8%, respectively. The effective tax rates for the nine months ended September 30, 2013 and 2012 were 38.2% and 41.7%, respectively. Unrealized derivative activity affects the taxable income calculation in certain jurisdictions, but not all, resulting in effective tax rates different than our expected 37%-38% range. These effective tax rate fluctuations are magnified when net income approaches zero.
	As of September 30, 2013, we did not have a liability for uncertain tax positions, and as such, we had not accrued related interest or penalties. The tax years 2010 through 2012 remain open to examination for federal income tax purposes and by the other major taxing jurisdictions to which we are subject.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Stock-Based Compensation Text Block	'
	Stock-Based Compensation:
	As of the dates indicated, our stock-based compensation consisted of the following:
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
			(In millions)
	Equity awards		$	12			$	13			$	35			$	36
	Liability awards		13				—				14				1
	Total stock-based compensation		25				13				49				37
	Capitalized in oil and gas properties		(7		)		(3		)		(14		)		(10		)
	Net stock-based compensation expense		$	18			$	10			$	35			$	27
	As of September 30, 2013, we had approximately $157 million of total unrecognized stock-based compensation expense related to unvested stock-based compensation awards. The full amount is expected to be recognized within four years.
	Equity Awards
	Equity awards consist of service-based and performance- or market- based restricted stock units, stock options and stock purchase options under the Employee Stock Purchase Plan.
	Stock-based compensation classified as equity awards to employees and non-employee directors are currently granted under the 2011 Omnibus Stock Plan. The fair value of grants is determined utilizing the Black-Scholes option-pricing model for stock options and a lattice-based model for our performance and market-based restricted stock and restricted stock units. Compensation expense for equity awards is expected to be recognized on a straight-line basis over the applicable remaining vesting periods.
	Restricted Stock.  The following table provides information about restricted stock and restricted stock unit activity:
			Service-Based			Performance/			Total			Weighted- Average Grant Date Fair Value per Share
			Shares			Market-Based			Shares
						Shares
			(In thousands, except per share data)
	Non-vested shares outstanding at December 31, 2012		2,371			438			2,809			$	43.31
	Granted		2,290			300			2,590			27.16
	Forfeited		(540	)		(22	)		(562	)		39.46
	Vested		(1,136	)		—			(1,136	)		39.63
	Non-vested shares outstanding at September 30, 2013		2,985			716			3,701			$	33.72
	Stock Options.  The following table provides information about stock option activity:
			Number of Shares Underlying Options			Weighted-				Weighted-				Weighted-		Aggregate
						Average				Average				Average		Intrinsic
						Exercise				Grant Date				Remaining		Value(1)
						Price				Fair Value				Contractual Life
						per Share				per Share
			(In thousands)											(In years)		(In millions)
	Outstanding at December 31, 2012		901			$	38.06							3.3		$	1
	Granted		—			—				$	—
	Exercised		(42	)		18.1										1
	Forfeited		(144	)		37.92
	Outstanding at September 30, 2013		715			$	39.26							2.7		$	—
	Exercisable at September 30, 2013		715			$	39.26							2.7		$	—
	________
	-1	The intrinsic value of a stock option is the amount by which the market value of our common stock at the indicated date, or at the time of exercise, exceeds the exercise price of the option.
	On September 30, 2013, the last reported sales price of our common stock on the New York Stock Exchange was $27.37 per share.
	Employee Stock Purchase Plan.  During the first six months of 2013, options to purchase approximately 99,000 shares of our common stock, which were issued under our employee stock purchase plan, were exercised. The weighted-average fair value of each option was $6.90 per share. The fair value of the options granted was determined using the Black-Scholes option valuation method assuming no dividends, a risk-free weighted-average interest rate of 0.11%, an expected life of six months and weighted-average volatility of 40%.
	On July 1, 2013, options to purchase approximately 87,000 shares of our common stock were issued under our employee stock purchase plan. The weighted-average fair value of each option was $6.20 per share. The fair value of the options granted was determined using the Black-Scholes option valuation method assuming no dividends, a risk-free weighted-average interest rate of 0.09%, an expected life of six months and weighted-average volatility of 38%.
	Liability Awards
	Liability awards consist of cash-based performance awards under the Stockholder Value Appreciation Program and cash-settled restricted stock units.
	Stockholder Value Appreciation Program.  In September 2013, the Compensation and Management Development Committee of the Board approved the Stockholder Value Appreciation Program, to be administered under the 2011 Omnibus Stock Plan. The SVAP pays substantially all full-time domestic, non-executive employees a cash payment based on a percentage of salary upon each incremental $5 increase in our 30 calendar day average share price. The first price threshold that would trigger a payment under the SVAP was $27.50. The SVAP’s performance period lasts through December 31, 2015.
	The fair value of the SVAP liability was $8 million as of September 30, 2013. The fair value was determined using a Monte Carlo simulation assuming no dividends, a risk-free weighted-average interest rate of 0.41%, an expected life of 2.25 years and an average of implied and historical stock price volatility of 42%. On October 12, 2013, the first price threshold of $27.50 was achieved, which led to a cash payment of approximately $13 million that was paid to eligible employees on October 25, 2013. As of September 30, 2013, we had unrecognized stock-based compensation expense of approximately $35 million for the SVAP.
	Cash-Settled Restricted Stock Units.  During 2011 and 2013, we granted cash-settled restricted stock units to employees that vest over three years. The value of the awards, and the associated stock-based compensation expense, is based on the Company’s stock price. During the nine months ended September 30, 2013, approximately 83,000 cash-settled restricted stock units vested and settled for approximately $2 million. During the nine months ended September 30, 2012, approximately 44,000 cash-settled restricted stock units vested and settled for approximately $2 million. As of September 30, 2013, we had approximately 1.1 million cash-settled restricted stock units outstanding and unrecognized stock-based compensation expense of approximately $23 million for cash-settled restricted stock units.

Voluntary_Severance_Program

Voluntary Severance Program	9 Months Ended
	Sep. 30, 2013
Restructuring and Related Activities [Abstract]	'
Restructuring and Related Activities Disclosure [Text Block]	'
	Voluntary Severance Program:
	During the second quarter of 2013, we implemented a voluntary severance program in order to lower cash operating costs and change the structure of our organization to better align with our focus on domestic resource plays. Through September 30, 2013, the estimated total expense of the voluntary severance program was approximately $9 million, all of which has been recognized in "General and administrative" expense in our consolidated statement of operations.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies Text Block	'
	Commitments and Contingencies:
	We have been named as a defendant in a number of lawsuits and are involved in various other disputes, all arising in the ordinary course of our business, such as (a) claims from royalty owners for disputed royalty payments, (b) commercial disputes, (c) personal injury claims and (d) property damage claims. Although the outcome of these lawsuits and disputes cannot be predicted with certainty, we do not expect these matters to have a material adverse effect on our financial positions, cash flows or results of operations.

Supplemental_Cash_Flows_Inform

Supplemental Cash Flows Information	9 Months Ended
	Sep. 30, 2013
Supplemental Cash Flow Information [Abstract]	'
Supplemental Cash Flows Information Text Block	'
	Supplemental Cash Flows Information:
	The following table presents information about supplemental cash flows for the following periods:
		Nine Months Ended
		September 30,
		2013			2012
		(In millions)
	Non-cash items excluded from the statement of cash flows:
	(Increase) decrease in accrued capital expenditures	$	(55	)	$	(101	)
	(Increase) decrease in asset retirement costs	(8		)	(14		)

Related_Party_Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2013
Related Party Transactions [Abstract]	'
Related Party Transaction Text Block	'
	Related-Party Transactions:
	Kevin M. Robinson, our Vice President — Asia, and Susan G. Riggs, our Treasurer, are minority owners of Huffco International L.L.C. (Huffco). In May 1997, before Mr. Robinson and Ms. Riggs joined us, we acquired from Huffco an entity now known as Newfield China, LDC, the owner of a 12% interest in a three-field unit located on Blocks 4/36 and 5/36 in Bohai Bay, offshore China. Huffco retained preferred shares of Newfield China that provided for an aggregate dividend equal to 10% of the excess of proceeds received by Newfield China from the sale of oil, gas and other minerals over all costs incurred with respect to exploration and production in Block 5/36, plus the cash purchase price we paid Huffco for Newfield China ($6 million). During the nine months ended September 30, 2013 and the years ended December 31, 2012 and 2011, Newfield China paid $2 million, $7 million and $5 million, respectively, of dividends to Huffco on the preferred shares of Newfield China. During the third quarter, we purchased from Huffco the outstanding preferred shares of Newfield China for approximately $20 million. The repurchase of the preferred shares was recorded as a charge against retained earnings.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	Subsequent Events:
	On October 22, 2013, Newfield International Holdings Inc, a wholly-owned subsidiary of the Company, entered into a stock purchase agreement to sell our Malaysian business to SapuraKencana Petroleum Berhad, a Malaysian public company (SapuraKencana), for approximately $898 million in cash (subject to customary purchase price adjustments). This transaction requires the approval of SapuraKencana's shareholders and Petroliam Nasional Berhad (PETRONAS). Following approval by SapuraKencana shareholders, we intend to offer preferential rights to our partners under the applicable Joint Operating Agreements. We expect the transaction to close in early 2014. As discussed in Note 3, our Malaysia operations are classified as discontinued operations at September 30, 2013, and the historical results of operations for all of our international operations are reflected in our financial statements as “discontinued operations.”

Organization_and_Summary_of_Si1

Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Organization and Principles of Consolidation	'
	Organization and Principles of Consolidation
	We are an independent energy company engaged in the exploration, development and production of crude oil, natural gas and natural gas liquids (NGLs). Our principal domestic areas of operation include the Mid-Continent, the Rocky Mountains and the onshore Gulf Coast.
	Our consolidated financial statements include the accounts of Newfield Exploration Company, a Delaware corporation, and its subsidiaries. We proportionately consolidate our interests in oil and natural gas exploration and production ventures and partnerships in accordance with industry practice. All significant intercompany balances and transactions have been eliminated. Unless otherwise specified or the context otherwise requires, all references in these notes to “Newfield,” “we,” “us,” “our” or the “Company” are to Newfield Exploration Company and its subsidiaries.
	These unaudited consolidated financial statements reflect, in the opinion of our management, all adjustments, consisting only of normal and recurring adjustments, necessary to fairly state our financial position as of and results of operations for the periods presented. These financial statements have been prepared in accordance with the instructions to Form 10-Q and, therefore, do not include all disclosures required for financial statements prepared in conformity with accounting principles generally accepted in the United States of America. Interim period results are not necessarily indicative of results of operations or cash flows for a full year.
	These consolidated financial statements and notes should be read in conjunction with our audited consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2012.
Discontinued Operations, Policy [Policy Text Block]	'
	Discontinued Operations
	Following our decision to evaluate strategic alternatives for our businesses in Malaysia and China and the resulting assets-held-for-sale classification in the second quarter of 2013, the results of our international operations, which focus on offshore developments in Malaysia and China, are reflected separately as discontinued operations in the consolidated statement of operations on a line immediately after “Income (loss) from continuing operations.” See Note 3, “Discontinued Operations,” for additional disclosures. These financial statements and notes are inclusive of our international operations unless otherwise noted.
Dependence on Oil and Gas Prices	'
	Dependence on Commodity Prices
	As an independent oil and natural gas producer, our revenue, profitability and future rate of growth are substantially dependent on prevailing prices for oil, natural gas and NGLs. Historically, the energy markets have been very volatile, and there can be no assurance that commodity prices will not be subject to wide fluctuations in the future. A substantial or extended decline in commodity prices could have a material adverse effect on our financial position, results of operations, cash flows and access to capital and on the quantities of oil, natural gas and NGL reserves that we can economically produce.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America requires our management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, the reported amounts of revenues and expenses during the reporting period and the quantities and values of proved oil, natural gas and NGL reserves used in calculating depletion and assessing impairment of our oil and gas properties. Actual results could differ significantly from these estimates. Our most significant financial estimates are associated with our estimated proved oil, natural gas and NGL reserves and the fair value of our derivative positions.
Investments	'
	Investments
	Investments consist of debt and equity securities, as well as auction rate securities, a majority of which are classified as “available-for-sale” and stated at fair value. Accordingly, unrealized gains and losses and the related deferred income tax effects are excluded from earnings and reported as a separate component within the consolidated statement of comprehensive income. Realized gains or losses are computed based on specific identification of the securities sold. We regularly assess our investments for impairment and consider any impairment to be other than temporary if we intend to sell the security, it is more likely than not that we will be required to sell the security, or we do not expect to recover our cost of the security. We realized interest income and net gains on our investment securities of approximately $1 million for each of the three-month periods ended September 30, 2013 and 2012 and approximately $3 million and $2 million for each of the nine-month periods ended September 30, 2013 and 2012, respectively.
Inventories	'
	Inventories
	Inventories primarily consist of tubular goods and well equipment held for use in our oil and natural gas operations and oil produced but not sold in our offshore operations in Malaysia and China. See Note 3, "Discontinued Operations" for details on our international crude oil inventory. Tubular goods and well equipment inventories are carried at the lower of cost or market.
Oil and Gas Properties	'
	Oil and Gas Properties
	We use the full cost method of accounting for our oil and gas producing activities. Under this method, all costs incurred in the acquisition, exploration and development of oil and gas properties, including salaries, benefits and other internal costs directly attributable to these activities, are capitalized into cost centers that are established on a country-by-country basis. We capitalized approximately $35 million and $29 million of internal costs during the three-month periods ended September 30, 2013 and 2012, respectively, and approximately $108 million and $87 million during the nine-month periods ended September 30, 2013 and 2012, respectively. Interest expense related to unproved properties also is capitalized into oil and gas properties.
	Proceeds from the sale of oil and gas properties are applied to reduce the costs in the applicable cost center unless the reduction would significantly alter the relationship between capitalized costs and proved reserves, in which case a gain or loss is recognized.
	Capitalized costs and estimated future development costs are amortized using a unit-of-production method based on proved reserves associated with the applicable cost center. For each cost center, the net capitalized costs of oil and gas properties are limited to the lower of the unamortized cost or the cost center ceiling. A particular cost center ceiling is equal to the sum of:
	•	the present value (10% per annum discount rate) of estimated future net revenues from proved reserves using oil, natural gas and NGL reserve estimation requirements, which require use of the unweighted average first-day-of-the-month commodity prices for the prior 12 months, adjusted for market differentials (SEC pricing), applicable to our reserves (including the effects of hedging contracts that are designated for hedge accounting, if any); plus
	•	the cost of properties not included in the costs being amortized, if any; less
	•	related income tax effects.
	If net capitalized costs of oil and gas properties exceed the cost center ceiling, we are subject to a ceiling test writedown to the extent of such excess. If required, a ceiling test writedown reduces earnings and stockholders’ equity in the period of occurrence and, holding other factors constant, results in lower depreciation, depletion and amortization expense in future periods.
	The risk that we will be required to writedown the carrying value of our oil and gas properties increases when oil, natural gas and NGL prices decrease significantly for a prolonged period of time or if we have substantial downward revisions in our estimated proved reserves. At September 30, 2013, the ceiling value of our reserves was calculated based upon SEC pricing of $3.61 per MMBtu for natural gas and $95.15 per barrel of oil. Using these prices, the cost center ceiling with respect to our domestic full cost pool exceeded the net capitalized costs of the respective cost centers. As such, no ceiling test writedown was required at September 30, 2013. If there are declines in SEC pricing of oil and natural gas subsequent to September 30, 2013, we may be required to record a ceiling test writedown in future periods.
	At December 31, 2012, the ceiling value of our reserves was calculated based upon SEC pricing of $2.76 per MMBtu for natural gas and $94.84 per barrel of oil. Using these prices, the unamortized net capitalized costs of our domestic oil and gas properties exceeded the ceiling amount by, and caused a writedown of, approximately $1.5 billion ($948 million, after-tax).
Other Property and Equipment	'
	Other Property and Equipment
	Furniture, fixtures and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives, which range from three to seven years. Gathering systems and equipment are recorded at cost and depreciated using the straight-line method over their estimated useful lives of 25 years.
Segment Reporting, Policy [Policy Text Block]	'
	Segment Reporting
	Our continuing operations are comprised of a single business segment, the domestic exploration, development and production of oil and natural gas. Prior to classifying our international businesses as held-for-sale and discontinued operations, we reported business segments for Malaysia and China.
Accounting for Asset Retirement Obligations	'
	Accounting for Asset Retirement Obligations
	The change in our asset retirement obligation (ARO) is set forth below (in millions):
	Balance at January 1, 2013	$	142
	Accretion expense	8
	Additions	6
	Revisions	2
	Settlements	(8		)
	Balance at September 30, 2013	150
	Less: Current portion of ARO at September 30, 2013	(6		)
	Total long-term ARO at September 30, 2013	$	144
Derivative Financial Instruments	'
	Derivative Financial Instruments
	Our derivative financial instruments are recorded on the consolidated balance sheet at fair value with changes in the derivative’s fair value recognized in current earnings. All of the derivative instruments that we utilize are to manage the price risk attributable to our expected oil and gas production. We have elected not to designate price-risk management activities as accounting hedges.
	The related cash flow impact of our derivative activities is reflected as cash flows from operating activities. See Note 5, “Derivative Financial Instruments,” for a more detailed discussion of our derivative activities.
Offsetting Fair Value	'
	Offsetting Assets and Liabilities
	Our derivative financial instruments are subject to master netting arrangements and are reflected on our consolidated balance sheet accordingly. See Note 5, “Derivative Financial Instruments,” for details regarding the gross amounts, as well as the impact of our netting arrangements on our net derivative position. We only offset assets and liabilities in relation to our derivative financial instruments.
New Accounting Requirements	'
	New Accounting Requirements
	In December 2011, the FASB issued guidance regarding the disclosure of offsetting assets and liabilities. The guidance requires disclosure of both gross and net information about instruments and transactions eligible for offset arrangement. The guidance is effective for interim and annual periods beginning on or after January 1, 2013. We adopted the guidance in the quarter ended March 31, 2013. Adoption of the additional disclosures regarding offsetting assets and liabilities did not have a material impact on our financial position or results of operations.
	In February 2013, the FASB issued guidance regarding the reporting of amounts reclassified out of accumulated other comprehensive income. The guidance is effective for interim and annual periods beginning after December 15, 2012. We adopted the guidance in the quarter ended March 31, 2013. Adoption of the new reporting guidance did not have a material impact on our financial position or results of operations as we did not have reclassifications during the periods presented.

Organization_and_Summary_of_Si2

Organization and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Change in ARO (asset retirement obligation)	'
	Balance at January 1, 2013	$	142
	Accretion expense	8
	Additions	6
	Revisions	2
	Settlements	(8		)
	Balance at September 30, 2013	150
	Less: Current portion of ARO at September 30, 2013	(6		)
	Total long-term ARO at September 30, 2013	$	144

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share Table	'
			Three Months Ended						Nine Months Ended
			September 30,						September 30,
			2013			2012			2013			2012
			(In millions, except per share data)
	Income (numerator):
	Income (loss) from continuing operations		$	(4	)	$	(82	)	$	77		$	21
	Income from discontinued operations, net of tax		31			49			53			197
	Net income (loss)		27			(33		)	130			218
	Repurchase of preferred shares of subsidiary(3)		(20		)	—			(20		)	—
	Net income (loss) attributable to common shareholders		$	7		$	(33	)	$	110		$	218
	Weighted-average shares (denominator):
	Weighted-average shares — basic		136			135			135			134
	Dilution effect of stock options and unvested restricted stock and restricted stock units outstanding at end of period(1) (2)		—			—			1			1
	Weighted-average shares — diluted		136			135			136			135
	Earnings per share:
	Basic:
	Income (loss) from continuing operations		$	(0.03	)	$	(0.61	)	$	0.57		$	0.15
	Income from discontinued operations before preferred share repurchase		0.23			0.37			0.39			1.47
	Repurchase of preferred shares of subsidiary(3)		(0.15		)	—			(0.15		)	—
	Income from discontinued operations		0.08			0.37			0.24			1.47
	Basic earnings (loss) per share		$	0.05		$	(0.24	)	$	0.81		$	1.62
	Diluted:
	Income (loss) from continuing operations		$	(0.03	)	$	(0.61	)	$	0.57		$	0.15
	Income from discontinued operations before preferred share repurchase		0.23			0.37			0.39			1.46
	Repurchase of preferred shares of subsidiary(3)		(0.15		)	—			(0.15		)	—
	Income from discontinued operations		0.08			0.37			0.24			1.46
	Diluted earnings (loss) per share		$	0.05		$	(0.24	)	$	0.81		$	1.61
	_______
	-1	The effect of unvested restricted stock or restricted stock units and stock options has not been included in the calculation of the shares outstanding for diluted EPS for the three months ended September 30, 2013 and 2012, as their effect would have been anti-dilutive. Had we recognized income from continuing operations for these periods, incremental shares attributable to the assumed vesting of unvested restricted stock and restricted stock units and the assumed exercise of outstanding stock options would have increased diluted weighted-average shares outstanding by 0.7 million and 0.6 million shares for the three months ended September 30, 2013 and 2012, respectively.
	-2	Excludes 4.1 million and 3.0 million shares of unvested restricted stock or restricted stock units and stock options for the nine-month periods ended September 30, 2013 and 2012, respectively, because including the effect would have been anti-dilutive.
	-3	The numerator includes an adjustment of $20 million related to the repurchase of preferred shares of a now wholly-owned subsidiary, which reduces net income (loss) for purposes of earnings per share for the three- and nine-month periods ended September 30, 2013. The subsidiary is part of our discontinued operations. See Note 15, "Related Party Transactions" for additional information.

Discontinued_Operations_Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	'
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013			2012
		(In millions)
	Oil and gas revenues	$	189		$	245		$	659		$	797
	Operating expenses	128			158			501			472
	Income from discontinued operations	61			87			158			325
	Other income (expense)	(1		)	(3		)	(2		)	(3		)
	Income from discontinued operations before income taxes	60			84			156			322
	Income tax provision (benefit):
	Current	10			47			65			138
	Deferred	19			(12		)	38			(13		)
	Total income tax provision (benefit)	29			35			103			125
	Income from discontinued operations, net of tax	$	31		$	49		$	53		$	197
Schedule of Disposal Groups, Including Discontinued Operations, Balance Sheet [Table Text Block]	'
		September 30,			December 31,
		2013			2012
		(In millions)
	Current assets:
	Cash and cash equivalents	$	69		$	76
	Accounts receivable	144			207
	Inventories	113			91
	Other current assets	27			31
	Total current assets	353			405
	Noncurrent assets:
	Oil and gas properties, net of accumulated depreciation, depletion and amortization of $1,032 and $843 as of September 30, 2013 and December 31, 2012, respectively	882			781
	Deferred taxes	27			24
	Other assets	4			4
	Total noncurrent assets	913			809
	Total assets	$	1,266		$	1,214
	Current liabilities:
	Accounts payable	$	41		$	50
	Accrued liabilities	285			269
	Other current liabilities	17			21
	Total current liabilities	343			340
	Noncurrent liabilities:
	Asset retirement obligations	41			38
	Deferred taxes	82			41
	Other liabilities	14			23
	Total noncurrent liabilities	137			102
	Total liabilities	$	480		$	442

Oil_and_Gas_Assets_Tables

Oil and Gas Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Oil and Gas Property [Abstract]	'
Costs incurred by year for oil and gas properties not subject to amortization	'
		Costs Incurred In
		2013			2012			2011		2010 and Prior		Total
		(In millions)
	Acquisition costs	$	116		$	112		$	252	$	355	$	835
	Exploration costs	491			28			13		36		568
	Development costs	1			31			39		—		71
	Fee mineral interests	—			—			—		23		23
	Capitalized interest	40			67			62		—		169
	Total oil and gas properties not subject to amortization	$	648		$	238		$	366	$	414	$	1,666
Capitalized Costs Relating to Oil and Gas Producing Activities and Other PPE [Table Text Block]	'
		September 30,			December 31,
		2013			2012
		(In millions)
	Oil and gas properties:
	Subject to amortization	$	14,019		$	12,647
	Not subject to amortization	1,666			1,485
	Gross oil and gas properties	15,685			14,132
	Accumulated depreciation, depletion and amortization	(8,035		)	(7,378		)
	Net oil and gas properties	7,650			6,754
	Other property and equipment:
	Furniture, fixtures and equipment	143			141
	Gathering systems and equipment	92			73
	Accumulated depreciation and amortization	(75		)	(66		)
	Net other property and equipment	160			148
	Total property and equipment, net	$	7,810		$	6,902

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments and Hedges, Assets [Abstract]	'
Outstanding contracts that are not designated for hedge accounting	'
	Natural Gas
						NYMEX Contract Price Per MMBtu
														Collars								Estimated Fair Value Asset (Liability)
	Period and Type of Instrument		Volume in MMMBtus			Swaps (Weighted Average)				Sold Puts (Weighted Average)				Floors (Weighted Average)				Ceilings (Weighted Average)
																						(In millions)
	2013:00:00
	Fixed-price swaps		13,800			$	4.09			—				—				—				$	7
	Collars with sold puts(A)		6,770			3.44				$	3.82			$	5.24			$	6.2			7
	Collars with sold puts		4,575			—				3				3.75				4.75				1
	2014:00:00
	Fixed-price swaps		85,775			3.98				—				—				—				10
	Collars		23,725			—				—				3.75				4.62				4
	2015:00:00
	Fixed-price swaps		49,275			4.28				—				—				—				11
	Collars		38,325			—				—				3.93				4.74				6
	Total																					$	46
	________
	(A)	During the first quarter of 2012, natural gas spot market prices were below the puts we sold on our collar with sold put positions for April through December 2012 and the full-year 2013, exposing us further to the softening natural gas spot market. As a result, during the first quarter of 2012, we entered into additional swap positions in the over-the-counter market that effectively prevented any further erosion in the value of our natural gas collar with sold put positions. The new swap positions added during the first quarter of 2012 were for the same volumes as our full-year 2013 collar with sold put positions. The economics from the combination of these additional swap positions and our natural gas collar with sold put positions will result in an effective average fixed price of $4.86 per MMBtu as long as natural gas spot prices for the respective time periods settle below the puts we sold on our collar with sold put positions. In the event natural gas spot prices settle above the ceilings on our associated collar with sold put positions, we would not recover the difference through the sale of our production as we would realize losses on both instruments discussed above.
	Crude Oil
						NYMEX Contract Price Per Bbl
														Collars								Estimated Fair Value
	Period and Type of Instrument		Volume in MBbls			Swaps				Sold Puts				Floors				Ceilings				Asset (Liability)
						(Weighted Average)				(Weighted Average)				(Weighted Average)				(Weighted Average)
																						(In millions)
	2013:00:00
	Fixed-price swaps		213			$	91.1			—				—				—				$	(2	)
	Fixed-price swaps with sold puts		920			97.49				$	75			—				—				(4		)
	Collars with sold puts		2,546			—				80				$	95			$	115.59			—
	2014:00:00
	Fixed-price swaps		7,127			89.89				—				—				—				(36		)
	Fixed-price swaps with sold puts		5,840			95.16				75				—				—				(4		)
	Collars with sold puts		2,190			—				75.83				90.83				102.93				(2		)
	2015:00:00
	Fixed-price swaps		6,567			90.39				—				—				—				12
	Fixed-price swaps with sold puts		3,107			90.04				66.53												3
	Swaptions(A)		—			90				—				—				—				(3		)
	Total																					$	(36	)
	________
	(A)	During the third quarter of 2013, we sold crude oil swaption contracts that would potentially hedge 1,460 MBbls of calendar year 2015 production if exercised on their expiration date in the fourth quarter of 2013. These contracts give the counterparties the option to enter into swap contracts with us at $90.00/Bbl for calendar year 2015. We received premiums of $3 million upon execution of these contracts, which were recorded in current "Derivative liabilities" on our consolidated balance sheet.
Derivative financial instruments recorded in balance sheet	'
			Derivative Assets																Derivative Liabilities
			Gross Fair Value				Offset in Balance Sheet				Balance Sheet Location								Gross Fair Value				Offset in Balance Sheet		Balance Sheet Location
											Current				Noncurrent										Current			Noncurrent
	September 30, 2013		(In millions)																(In millions)
	Natural gas positions		$	51			$	(4	)		$	29			$	18			$	(5	)		$	4	$	(1	)	$	—
	Oil positions		23				(10		)		—				13				(59		)		10		(48		)	(1		)
	Total		$	74			$	(14	)		$	29			$	31			$	(64	)		$	14	$	(49	)	$	(1	)
	December 31, 2012
	Natural gas positions		$	86			$	(5	)		$	79			$	2			$	(16	)		$	5	$	(4	)	$	(7	)
	Oil positions		77				(16		)		46				15				(26		)		16		(2		)	(8		)
	Total		$	163			$	(21	)		$	125			$	17			$	(42	)		$	21	$	(6	)	$	(15	)
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance [Table Text Block]	'
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
			(In millions)
	Derivatives not designated as hedging instruments:
	Realized gain (loss) on natural gas positions		$	19			$	37			$	51			$	135
	Realized gain (loss) on oil positions		(12		)		3				(9		)		(4		)
	Realized gain (loss) on basis positions		—				(3		)		—				(8		)
	Total realized gain(1)		7				37				42				123
	Unrealized gain (loss) on natural gas positions		(6		)		(79		)		(24		)		(162		)
	Unrealized gain (loss) on oil positions		(100		)		(59		)		(84		)		92
	Unrealized gain (loss) on basis positions		—				3				—				8
	Total unrealized loss		(106		)		(135		)		(108		)		(62		)
	Total		$	(99	)		$	(98	)		$	(66	)		$	61

Accounts_Receivable_Tables

Accounts Receivable (Tables)	9 Months Ended
	Sep. 30, 2013
Accounts Receivable, Net, Current [Abstract]	'
Accounts Receivable	'
		September 30,		December 31,
		2013		2012
		(In millions)
	Revenue	$	249	$	291
	Joint interest	173		154
	Other	19		8
	Reserve for doubtful accounts	—		(1		)
	Total accounts receivable	$	441	$	452

Accrued_Liabilities_Tables

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2013
Accrued Liabilities, Current [Abstract]	'
Accrued Liabilities	'
		September 30,		December 31,
		2013		2012
		(In millions)
	Revenue payable	$	158	$	95
	Accrued capital costs	435		355
	Accrued lease operating expenses	64		95
	Employee incentive expense	39		50
	Accrued interest on debt	46		43
	Taxes payable	97		108
	Other	54		55
	Total accrued liabilities	$	893	$	801

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Table Text Block Supplement [Abstract]	'
Fair value by measurement classification and type Table	'
		Fair Value Measurement Classification
		Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)			Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)			Total
		(In millions)
	As of December 31, 2012:
	Money market fund investments	$	22		$	—		$	—		$	22
	Deferred compensation plan assets	6			—			—			6
	Investments available-for-sale:
	Equity securities	7			—			—			7
	Auction rate securities	—			—			36			36
	Oil and gas derivative swap contracts	—			6			—			6
	Oil and gas derivative option contracts	—			—			115			115
	Stock-based compensation liability awards	(2		)	—			—			(2		)
	Total	$	33		$	6		$	151		$	190
	As of September 30, 2013:
	Money market fund investments	$	11		$	—		$	—		$	11
	Deferred compensation plan assets	8			—			—			8
	Investments available-for-sale:
	Equity securities	7			—			—			7
	Auction rate securities	—			—			39			39
	Oil and gas derivative option contracts	—			—			10			10
	Stock-based compensation liability awards	(7		)	—			(8		)	(15		)
	Total	$	19		$	—		$	41		$	60
Fair value changes level 3 Table	'
		Investments			Derivatives			Stock-based Compensation			Total
		(In millions)
	Balance at January 1, 2012	$	32		$	71		$	—		$	103
	Total realized or unrealized gains (losses):
	Included in earnings	—			100			—			100
	Included in other comprehensive income (loss)	2			—			—			2
	Purchases, issuances and settlements:
	Settlements	—			(69		)	—			(69		)
	Transfers in and out of Level 3	—			—			—			—
	Balance at September 30, 2012	$	34		$	102		$	—		$	136
	Change in unrealized gains or losses included in earnings relating to Level 3 instruments still held at September 30, 2012	$	—		$	67		$	—		$	67
	Balance at January 1, 2013	$	36		$	115		$	—		$	151
	Total realized or unrealized gains (losses):
	Included in earnings	—			(59		)	(8		)	(67		)
	Included in other comprehensive income (loss)	4			—			—			4
	Purchases, issuances and settlements:
	Settlements	(1		)	(46		)	—			(47		)
	Transfers in and out of Level 3	—			—			—			—
	Balance at September 30, 2013	$	39		$	10		$	(8	)	$	41
	Change in unrealized gains or losses included in earnings relating to Level 3 instruments still held at September 30, 2013	$	—		$	(8	)	$	(8	)	$	(16	)
Quantitative disclosures about unobservable inputs	'
		Estimated Fair Value Asset (Liability)			Quantitative Information about Level 3 Fair Value Measurements
	Instrument Type				Valuation Technique		Unobservable Input	Range
		(In millions)
	Oil option contracts	$	(10	)	Option model		NYMEX oil price forward curve	$	87.07		—		$	104.67
							Oil price volatility curves	15.48		%	—		26.34		%
							Credit risk	0.01		%	—		1.64		%
	Natural gas option contracts	$	20		Option model		NYMEX natural gas price forward curve	$	3.49		—		$	4.26
							Natural gas price volatility curves	20.47		%	—		32.03		%
							Credit risk	0.01		%	—		2.19		%
	SVAP	$	(8	)	Monte Carlo		Historical volatility						44.7		%
							Implied volatility	37.1		%	—		39.8		%
Estimated fair value of the debt instrument at the balance sheet date	'
		September 30,			December 31,
		2013			2012
		(In millions)
	5¾% Senior Notes due 2022	$	768		$	836
	5⅝% Senior Notes due 2024	970			1,074
	7⅛% Senior Subordinated Notes due 2018	623			630
	6⅞% Senior Subordinated Notes due 2020	737			749

Debt_Tables

Debt (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Instruments [Abstract]	'
Debt	'
		September 30,			December 31,
		2013			2012
		(In millions)
	Senior unsecured debt:
	Revolving credit facility - LIBOR based loans	$	440		$	—
	Total credit arrangements	440			—
	5¾% Senior Notes due 2022	750			750
	5⅝% Senior Notes due 2024	1,000			1,000
	Total senior unsecured debt	2,190			1,750
	7⅛% Senior Subordinated Notes due 2018	600			600
	6⅞% Senior Subordinated Notes due 2020	700			700
	Discount on notes	(5		)	(5		)
	Total long-term debt	$	3,485		$	3,045

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Provision for income taxes using federal statutory rate	'
		Three Months Ended						Nine Months Ended
		September 30,						September 30,
		2013			2012			2013		2012
		(In millions)
	Amount computed using the statutory rate	$	(3	)	$	(45	)	$	43	$	12
	Increase (decrease) in taxes resulting from:
	State and local income taxes, net of federal effect	1			(1		)	4		2
	Total provision (benefit) for income taxes	$	(2	)	$	(46	)	$	47	$	14

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Schedule of Stock Based Compensation Expense Table	'
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2013				2012				2013				2012
			(In millions)
	Equity awards		$	12			$	13			$	35			$	36
	Liability awards		13				—				14				1
	Total stock-based compensation		25				13				49				37
	Capitalized in oil and gas properties		(7		)		(3		)		(14		)		(10		)
	Net stock-based compensation expense		$	18			$	10			$	35			$	27
Stock Option Activity Table	'
			Number of Shares Underlying Options			Weighted-				Weighted-				Weighted-		Aggregate
						Average				Average				Average		Intrinsic
						Exercise				Grant Date				Remaining		Value(1)
						Price				Fair Value				Contractual Life
						per Share				per Share
			(In thousands)											(In years)		(In millions)
	Outstanding at December 31, 2012		901			$	38.06							3.3		$	1
	Granted		—			—				$	—
	Exercised		(42	)		18.1										1
	Forfeited		(144	)		37.92
	Outstanding at September 30, 2013		715			$	39.26							2.7		$	—
	Exercisable at September 30, 2013		715			$	39.26							2.7		$	—
	________
	-1	The intrinsic value of a stock option is the amount by which the market value of our common stock at the indicated date, or at the time of exercise, exceeds the exercise price of the option.
Restricted Stock and Restricted Stock Unit Activity Table	'
			Service-Based			Performance/			Total			Weighted- Average Grant Date Fair Value per Share
			Shares			Market-Based			Shares
						Shares
			(In thousands, except per share data)
	Non-vested shares outstanding at December 31, 2012		2,371			438			2,809			$	43.31
	Granted		2,290			300			2,590			27.16
	Forfeited		(540	)		(22	)		(562	)		39.46
	Vested		(1,136	)		—			(1,136	)		39.63
	Non-vested shares outstanding at September 30, 2013		2,985			716			3,701			$	33.72

Supplemental_Cash_Flows_Inform1

Supplemental Cash Flows Information (Tables)	9 Months Ended
	Sep. 30, 2013
Supplemental Cash Flow Information [Abstract]	'
Supplemental Cash Flows Information Schedule (Table)	'
		Nine Months Ended
		September 30,
		2013			2012
		(In millions)
	Non-cash items excluded from the statement of cash flows:
	(Increase) decrease in accrued capital expenditures	$	(55	)	$	(101	)
	(Increase) decrease in asset retirement costs	(8		)	(14		)

Organization_and_Summary_of_Si3

Organization and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
	MBbls		MBbls		MBbls
Change in ARO (asset retirement obligation)	'	'	'	'	'
Beginning Balance	'	'	$142,000,000	'	'
Accretion expense	'	'	8,000,000	'	'
Additions	'	'	6,000,000	'	'
Revisions	'	'	2,000,000	'	'
Settlements	'	'	-8,000,000	'	'
Ending Balance	150,000,000	'	150,000,000	'	142,000,000
Less: Current portion of ARO	-6,000,000	'	-6,000,000	'	-10,000,000
Total long-term ARO	144,000,000	'	144,000,000	'	132,000,000
Organization and Summary of Significant Accounting Policies (Textuals) [Abstract]	'	'	'	'	'
Realized interest income and gains on investment securities	1,000,000	1,000,000	3,000,000	2,000,000	'
Crude oil inventory (in barrels)	990,000	'	990,000	'	744,000
Crude oil inventory	79,000,000	'	79,000,000	'	64,000,000
Capitalization of internal costs per full cost method of accounting	35,000,000	29,000,000	108,000,000	87,000,000	'
Discount rate	'	'	10.00%	'	'
Unweighted average commodity price of natural gas based on first-day-of-the-month prices for the prior 12 months (per MMBtu)	3.61	'	3.61	'	2.76
Unweighted average commodity price of oil based on first-day-of-the-month prices for the prior 12 months (per barrel)	95.15	'	95.15	'	94.84
Capitalized Costs Exceeding Ceiling, Net	'	'	'	'	948,000,000
Capitalized Cost Exceeding Ceiling, Gross	'	'	'	'	$1,500,000,000
Statement [Line Items]	'	'	'	'	'
Property, Plant and Equipment, Useful Life	'	'	'25 years 0 months 0 days	'	'
Minimum [Member]	'	'	'	'	'
Statement [Line Items]	'	'	'	'	'
Property, Plant and Equipment, Useful Life	'	'	'3 years 0 months 0 days	'	'
Maximum [Member]	'	'	'	'	'
Statement [Line Items]	'	'	'	'	'
Property, Plant and Equipment, Useful Life	'	'	'7 years 0 months 0 days	'	'

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income (numerator):	'	'	'	'
Income (Loss) from Continuing Operations Attributable to Parent	($4)	($82)	$77	$21
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	31	49	53	197
Net income (loss)	27	-33	130	218
Preferred Stock Dividends and Other Adjustments	-20	0	-20	0
Net Income (Loss) Available to Common Stockholders, Basic	7	-33	110	218
Weighted average shares (denominator):	'	'	'	'
Weighted average shares - basic	136	135	135	134
Dilution effect of stock options and unvested restricted stock and restricted stock units outstanding at end of period	0	0	1	1
Weighted average shares - diluted	136	135	136	135
Basic --	'	'	'	'
Income (Loss) from Continuing Operations, Per Basic Share	($0.03)	($0.61)	$0.57	$0.15
Income (Loss) from Discontinued Operations, Net of Tax, Before Preferred Share Repurchase, Per Basic Share	$0.23	$0.37	$0.39	$1.47
Income (Loss) Attributable to Repurchase of Preferred Shares of Wholly-owned Subsidiary, Per Basic Share	($0.15)	$0	($0.15)	$0
Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share	$0.08	$0.37	$0.24	$1.47
Earnings (Loss) Per Share, Basic	$0.05	($0.24)	$0.81	$1.62
Diluted --	'	'	'	'
Income (Loss) from Continuing Operations, Per Diluted Share	($0.03)	($0.61)	$0.57	$0.15
Income (Loss) from Discontinued Operations, Net of Tax, Before Preferred Share Repurchase, Per Diluted Share	$0.23	$0.37	$0.39	$1.46
Income (Loss) Attributable to Repurchase of Preferred Shares of Wholly-owned Subsidiary, Per Diluted Share	($0.15)	$0	($0.15)	$0
Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share	$0.08	$0.37	$0.24	$1.46
Earnings (Loss) Per Share, Diluted	$0.05	($0.24)	$0.81	$1.61
Earnings Per Share (Textuals) [Abstract]	'	'	'	'
Incremental shares attributable to the assumed exercise of outstanding stock options and the assumed vesting of unvested restricted stock and restricted stock units	0.7	0.6	4.1	3
Payments for Repurchase of Preferred Stock and Preference Stock	$20	'	$20	$0

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
	MBbls		MBbls		MBbls
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Discontinued Operation, Tax Effect of Discontinued Operation	$29	$35	$103	$125	'
Not subject to amortization	115	'	115	'	'
Historical Effective Tax Rate, Discontinuing Operations	'	'	37.00%	'	'
Provision to Return Tax Adjustment, DIscontinued Operations	16	'	'	'	'
Disposal Group, Including Discontinued Operation, Revenue	189	245	659	797	'
Disposal Group, Including Discontinued Operation, Operating Expense	128	158	501	472	'
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	61	87	158	325	'
Discontinued Operation, Amount of Other Income (Loss) from Disposition of Discontinued Operations, before Income Tax	-1	-3	-2	-3	'
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	60	84	156	322	'
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	31	49	53	197	'
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents	69	'	69	'	76
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	144	'	144	'	207
Disposal Group, Including Discontinued Operation, Inventory	113	'	113	'	91
Disposal Group, Including Discontinued Operation, Other Current Assets	27	'	27	'	31
Assets of Disposal Group, Including Discontinued Operation, Current	353	'	353	'	405
Disposal Group, including Discontinued Operations, Oil and Gas Properties, Net	882	'	882	'	781
Disposal Group, Including Discontinued Operation, Deferred Tax Assets	27	'	27	'	24
Disposal Group, Including Discontinued Operation, Other Noncurrent Assets	4	'	4	'	4
Assets of Disposal Group, Including Discontinued Operation, Noncurrent	913	'	913	'	809
Assets of Disposal Group, Including Discontinued Operation	1,266	'	1,266	'	1,214
Disposal Group, Including Discontinued Operation, Accounts Payable	41	'	41	'	50
Disposal Group, Including Discontinued Operation, Accrued Liabilities	285	'	285	'	269
Disposal Group, Including Discontinued Operation, Other Current Liabilities	17	'	17	'	21
Liabilities of Disposal Group, Including Discontinued Operation, Current	343	'	343	'	340
Disposal Group, Including Discontinued Operations, Asset Retirement Obligations	41	'	41	'	38
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities	82	'	82	'	41
Disposal Group, Including Discontinued Operation, Other Noncurrent Liabilities	14	'	14	'	23
Liabilities of Disposal Group, Including Discontinued Operation, Noncurrent	137	'	137	'	102
Liabilities of Disposal Group, Including Discontinued Operation	480	'	480	'	442
Disposal Group, Including Discontinued Operations, Accumulated Depreciation, Depletion and Amortization, Property Plant and Equipment	1,032	'	1,032	'	843
Effective Income Tax Rate, Discontinuing Operations	48.20%	40.80%	65.70%	38.50%	'
Crude oil inventory in barrels	990,000	'	990,000	'	744,000
Energy Related Inventory, Petroleum	79	'	79	'	64
Current [Member]	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Discontinued Operation, Tax Effect of Discontinued Operation	10	47	65	138	'
Deferred [Member]	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Discontinued Operation, Tax Effect of Discontinued Operation	19	-12	38	-13	'
Costs incurred in 2010 and prior not subject to amortization [Member]	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Not subject to amortization	45	'	45	'	'
Costs incurred in 2011 not subject to amortization [Member]	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Not subject to amortization	2	'	2	'	'
Costs incurred in 2012 not subject to amortization [Member]	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Not subject to amortization	24	'	24	'	'
Costs incurred in 2013 not subject to amortization [Member]	'	'	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'
Not subject to amortization	$44	'	$44	'	'

Oil_and_Gas_Assets_Details

Oil and Gas Assets (Details) (USD $)	9 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Oil and gas properties:	'	'	'
Subject to amortization	$14,019	'	$12,647
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	1,666	'	1,485
Gross oil and gas properties	15,685	'	14,132
Capitalized Costs, Accumulated Depreciation, Depletion, Amortization and Valuation Allowance for Relating to Oil and Gas Producing Activities	-8,035	'	-7,378
Net oil and gas properties	7,650	'	6,754
Accumulated depreciation and amortization	-75	'	-66
Net other property and equipment	160	'	148
Total property and equipment, net	7,810	'	6,902
Cost of oil and gas properties not subject to amortization	'	'	'
Acquisition costs	835	'	'
Exploration costs	568	'	'
Development costs	71	'	'
Fee mineral interests	23	'	'
Capitalized interest	169	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	1,666	'	1,485
Oil and Gas Assets (Textuals) [Abstract]	'	'	'
Non Strategic Assets Sold	'	'	208
Percent of oil and gas properties not subject to amortization associated with unconventional resource plays	86.00%	'	'
Evaluation, in years, of conventional oil and gas properties not subject to amortization.	'P4Y	'	'
Proceeds from Sale of Oil and Gas Property and Equipment	25	382	630
Furniture and Fixtures [Member]	'	'	'
Oil and gas properties:	'	'	'
Other property and equipment	143	'	141
Gas Gathering and Processing Equipment [Member]	'	'	'
Oil and gas properties:	'	'	'
Other property and equipment	92	'	73
Costs incurred in 2013 not subject to amortization [Member]	'	'	'
Oil and gas properties:	'	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	648	'	'
Cost of oil and gas properties not subject to amortization	'	'	'
Acquisition costs	116	'	'
Exploration costs	491	'	'
Development costs	1	'	'
Fee mineral interests	0	'	'
Capitalized interest	40	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	648	'	'
Costs incurred in 2012 not subject to amortization [Member]	'	'	'
Oil and gas properties:	'	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	238	'	'
Cost of oil and gas properties not subject to amortization	'	'	'
Acquisition costs	112	'	'
Exploration costs	28	'	'
Development costs	31	'	'
Fee mineral interests	0	'	'
Capitalized interest	67	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	238	'	'
Costs incurred in 2011 not subject to amortization [Member]	'	'	'
Oil and gas properties:	'	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	366	'	'
Cost of oil and gas properties not subject to amortization	'	'	'
Acquisition costs	252	'	'
Exploration costs	13	'	'
Development costs	39	'	'
Fee mineral interests	0	'	'
Capitalized interest	62	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	366	'	'
Costs incurred in 2010 and prior not subject to amortization [Member]	'	'	'
Oil and gas properties:	'	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	414	'	'
Cost of oil and gas properties not subject to amortization	'	'	'
Acquisition costs	355	'	'
Exploration costs	36	'	'
Development costs	0	'	'
Fee mineral interests	23	'	'
Capitalized interest	0	'	'
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative	$414	'	'

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Textuals) (Details) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Derivative [Line Items]	'
Derivative Premium Received	$3
Total Derivative Counterparties	15
Primary Derivative Counterparties	9
Percent of future hedged production with primary counterparties	85.00%
Number of counterparties holding more than 25 percent of future hedge position.	0
Concentraction Of Future Hedged Production	15.00%
Oil contracts [Member]	'
Derivative [Line Items]	'
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	36
Year 2013 [Member] | Natural gas contracts [Member] | Swap [Member]	'
Derivative [Line Items]	'
Derivative, Swap Type, Average Fixed Price	4.09
Volume In Mmbtus	13,800,000
Year 2013 [Member] | Oil contracts [Member] | Swap [Member]	'
Derivative [Line Items]	'
Volume in MBbls	213,000
Derivative, Swap Type, Average Fixed Price	91.1
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	2
Year2015 [Member] | Natural gas contracts [Member] | Swap [Member]	'
Derivative [Line Items]	'
Derivative, Swap Type, Average Fixed Price	4.28
Volume In Mmbtus	49,275,000
Year2015 [Member] | Oil contracts [Member] | Swaption [Member]	'
Derivative [Line Items]	'
Volume in MBbls	1,460,000
Derivative, Swap Type, Average Fixed Price	90
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	$3
Year2015 [Member] | Oil contracts [Member] | Swap [Member]	'
Derivative [Line Items]	'
Volume in MBbls	6,567,000
Derivative, Swap Type, Average Fixed Price	90.39

Outstanding_Natural_Gas_Contra

Outstanding Natural Gas Contracts That Are Not Designated for Hedge Accounting (Details) (Natural gas contracts [Member], USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Derivative [Line Items]	'
Derivative Asset, Fair Value, Total	$46
Year 2013 [Member]	'
Derivative [Line Items]	'
Derivative, Natural Gas Weighted Average Price	4.86
Collars With Sold Puts [Member] | Year 2013 [Member]	'
Derivative [Line Items]	'
Natural Gas Volumes	4,575,000
Derivative Weighted Average Additional Put Price	3
Derivative, Weighted Average Floor Price	3.75
Derivative, Weighted Average Ceiling Price	4.75
Derivative Asset, Fair Value, Total	1
Collars [Member] | Year 2014 [Member]	'
Derivative [Line Items]	'
Natural Gas Volumes	23,725,000
Derivative, Weighted Average Floor Price	3.75
Derivative, Weighted Average Ceiling Price	4.62
Derivative Asset, Fair Value, Total	4
Collars [Member] | Year2015 [Member]	'
Derivative [Line Items]	'
Natural Gas Volumes	38,325,000
Derivative, Weighted Average Floor Price	3.93
Derivative, Weighted Average Ceiling Price	4.74
Derivative Asset, Fair Value, Total	6
Fixed-price swaps | Year 2013 [Member]	'
Derivative [Line Items]	'
Natural Gas Volumes	13,800,000
Derivative, Swap Type, Average Fixed Price	4.09
Derivative Asset, Fair Value, Total	7
Fixed-price swaps | Year 2014 [Member]	'
Derivative [Line Items]	'
Natural Gas Volumes	85,775,000
Derivative, Swap Type, Average Fixed Price	3.98
Derivative Asset, Fair Value, Total	10
Fixed-price swaps | Year2015 [Member]	'
Derivative [Line Items]	'
Natural Gas Volumes	49,275,000
Derivative, Swap Type, Average Fixed Price	4.28
Derivative Asset, Fair Value, Total	11
Collars With Sold Puts With Swaps [Member] | Year 2013 [Member]	'
Derivative [Line Items]	'
Natural Gas Volumes	6,770,000
Derivative, Swap Type, Average Fixed Price	3.44
Derivative Weighted Average Additional Put Price	3.82
Derivative, Weighted Average Floor Price	5.24
Derivative, Weighted Average Ceiling Price	6.2
Derivative Asset, Fair Value, Total	$7

Outstanding_Oil_Contracts_That

Outstanding Oil Contracts That Are Not Designated For Hedge Accounting (Details) (Oil contracts [Member], USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Derivative [Line Items]	'
Derivative Liability, Fair Value, Total	($36)
Fixed Price Swaps With Sold Puts [Member] | Year 2013 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	920,000
Derivative, Swap Type, Average Fixed Price	97.49
Derivative Weighted Average Additional Put Price	75
Derivative Liability, Fair Value, Total	-4
Fixed Price Swaps With Sold Puts [Member] | Year 2014 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	5,840,000
Derivative, Swap Type, Average Fixed Price	95.16
Derivative Weighted Average Additional Put Price	75
Derivative Liability, Fair Value, Total	-4
Fixed Price Swaps With Sold Puts [Member] | Year2015 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	3,107,000
Derivative, Swap Type, Average Fixed Price	90.04
Derivative Weighted Average Additional Put Price	66.53
Derivative Asset, Fair Value, Total	3
Collars With Sold Puts [Member] | Year 2013 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	2,546,000
Derivative Weighted Average Additional Put Price	80
Derivative, Weighted Average Floor Price	95
Derivative, Weighted Average Ceiling Price	116
Derivative Asset, Fair Value, Total	0
Collars With Sold Puts [Member] | Year 2014 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	2,190,000
Derivative Weighted Average Additional Put Price	75.83
Derivative, Weighted Average Floor Price	90.83
Derivative, Weighted Average Ceiling Price	103
Derivative Liability, Fair Value, Total	-2
Fixed-price swaps | Year 2013 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	213,000
Derivative, Swap Type, Average Fixed Price	91.1
Derivative Liability, Fair Value, Total	-2
Fixed-price swaps | Year 2014 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	7,127,000
Derivative, Swap Type, Average Fixed Price	89.89
Derivative Liability, Fair Value, Total	-36
Fixed-price swaps | Year2015 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	6,567,000
Derivative, Swap Type, Average Fixed Price	90.39
Derivative Asset, Fair Value, Total	12
Swaption [Member] | Year2015 [Member]	'
Derivative [Line Items]	'
Volume in MBbls	1,460,000
Derivative, Swap Type, Average Fixed Price	90
Derivative Liability, Fair Value, Total	($3)

Derivative_Financial_Instrumen3

Derivative Financial Instruments Recorded in Balance Sheet (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Derivative, Fair Value, Net [Abstract]	'	'
Derivative Asset Not Designated As Hedging Instrument, Fair Value	$74	$163
Derivative Liability Not Designated as Hedging Instrument Fair Value	-64	-42
Derivative Asset, Current	29	125
Derivative Asset, Noncurrent	31	17
Derivative Liability, Current	49	6
Derivative Liability, Noncurrent	1	15
Derivative Assets Offset Against Derivative Liabilities	14	21
Natural gas contracts [Member]	'	'
Derivative, Fair Value, Net [Abstract]	'	'
Derivative Asset Not Designated As Hedging Instrument, Fair Value	51	86
Derivative Liability Not Designated as Hedging Instrument Fair Value	-5	-16
Derivative Asset, Current	29	79
Derivative Asset, Noncurrent	18	2
Derivative Liability, Current	1	4
Derivative Liability, Noncurrent	0	7
Derivative Assets Offset Against Derivative Liabilities	4	5
Oil contracts [Member]	'	'
Derivative, Fair Value, Net [Abstract]	'	'
Derivative Asset Not Designated As Hedging Instrument, Fair Value	23	77
Derivative Liability Not Designated as Hedging Instrument Fair Value	-59	-26
Derivative Asset, Current	0	46
Derivative Asset, Noncurrent	13	15
Derivative Liability, Current	48	2
Derivative Liability, Noncurrent	1	8
Derivative Assets Offset Against Derivative Liabilities	$10	$16

Amount_of_Gain_Loss_Recognized

Amount of Gain Loss Recognized in Income Related to Derivative Financial Instruments (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]	'	'	'	'
Realized Gain (Loss) on Derivatives	$7	$37	$42	$123
Unrealized Gain (Loss) on Derivatives	-106	-135	-108	-62
Derivative, Gain (Loss) on Derivative, Net	-99	-98	-66	61
Natural gas contracts [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]	'	'	'	'
Realized Gain (Loss) on Derivatives	19	37	51	135
Unrealized Gain (Loss) on Derivatives	-6	-79	-24	-162
Oil contracts [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]	'	'	'	'
Realized Gain (Loss) on Derivatives	-12	3	-9	-4
Unrealized Gain (Loss) on Derivatives	-100	-59	-84	92
Basis contracts [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]	'	'	'	'
Realized Gain (Loss) on Derivatives	0	-3	0	-8
Unrealized Gain (Loss) on Derivatives	$0	$3	$0	$8

Accounts_Receivable_Details

Accounts Receivable (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Accounts Receivable	'	'
Accounts receivable	$441	$452
Revenue [Member]	'	'
Accounts Receivable	'	'
Accounts receivable	249	291
Other accounts receivable [Member]	'	'
Accounts Receivable	'	'
Accounts receivable	19	8
Allowance For Doubtful Accounts [Member]	'	'
Accounts Receivable	'	'
Accounts receivable	0	-1
Oil and Gas Joint Interest Billing [Member]	'	'
Accounts Receivable	'	'
Accounts receivable	$173	$154

Accrued_Liabilities_Details

Accrued Liabilities (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Accrued Liabilities	'	'
Accrued liabilities	$893	$801
Revenue payable [Member]	'	'
Accrued Liabilities	'	'
Accrued liabilities	158	95
Accrued capital costs [Member]	'	'
Accrued Liabilities	'	'
Accrued liabilities	435	355
Accrued lease operating expenses [Member]	'	'
Accrued Liabilities	'	'
Accrued liabilities	64	95
Employee incentive expense [Member]	'	'
Accrued Liabilities	'	'
Accrued liabilities	39	50
Accrued interest on debt [Member]	'	'
Accrued Liabilities	'	'
Accrued liabilities	46	43
Taxes payable [Member]	'	'
Accrued Liabilities	'	'
Accrued liabilities	97	108
Other accrued liabilities [Member]	'	'
Accrued Liabilities	'	'
Accrued liabilities	$54	$55

Fair_Value_Measurements_Textua

Fair Value Measurements (Textuals) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$41	$136	$151	$103
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Investment Income	-16	67	'	'
Money Market Funds, at Carrying Value	11	'	22	'
Deferred Compensation Plan Assets	8	'	6	'
Available-for-sale Securities, Fair Value Disclosure	39	'	36	'
Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment Gross Of Tax	-6	'	-9	'
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	-4	'	-6	'
Assets, Fair Value Disclosure	60	'	190	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	-67	100	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	4	2	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	-47	-69	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0	'	'
Obligations, Fair Value Disclosure	-15	'	-2	'
Natural gas contracts [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	46	'	'	'
Natural gas contracts [Member] | Options Held [Member]	'	'	'	'
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	20	'	'	'
Natural gas contracts [Member] | Minimum [Member] | Options Held [Member]	'	'	'	'
Fair Value Assumptions Expected Volatility Curves	20.47%	'	'	'
Fair Value Inputs, Entity Credit Risk	0.01%	'	'	'
Natural gas contracts [Member] | Maximum [Member] | Options Held [Member]	'	'	'	'
Fair Value Assumptions Expected Volatility Curves	32.03%	'	'	'
Fair Value Inputs, Entity Credit Risk	2.19%	'	'	'
Oil contracts [Member] | Minimum [Member] | Options Held [Member]	'	'	'	'
Fair Value Assumptions Expected Volatility Curves	15.48%	'	'	'
Fair Value Inputs, Entity Credit Risk	0.01%	'	'	'
Oil contracts [Member] | Maximum [Member] | Options Held [Member]	'	'	'	'
Fair Value Assumptions Expected Volatility Curves	26.34%	'	'	'
Fair Value Inputs, Entity Credit Risk	1.64%	'	'	'
Auction Rate Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	39	'	36	'
Swap [Member]	'	'	'	'
Derivative Assets	'	'	6	'
Commodity Option [Member]	'	'	'	'
Derivative Assets	10	'	115	'
Equity Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	7	'	7	'
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member]	'	'	'	'
Money Market Funds, at Carrying Value	11	'	22	'
Deferred Compensation Plan Assets	8	'	6	'
Assets, Fair Value Disclosure	19	'	33	'
Obligations, Fair Value Disclosure	-7	'	-2	'
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Auction Rate Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	0	'	0	'
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Swap [Member]	'	'	'	'
Derivative Assets	'	'	0	'
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Commodity Option [Member]	'	'	'	'
Derivative Assets	0	'	0	'
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Equity Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	7	'	7	'
Significant Other Observable Fair Value Inputs (Level 2) [Member]	'	'	'	'
Money Market Funds, at Carrying Value	0	'	0	'
Deferred Compensation Plan Assets	0	'	0	'
Assets, Fair Value Disclosure	0	'	6	'
Obligations, Fair Value Disclosure	0	'	0	'
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Auction Rate Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	0	'	0	'
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Swap [Member]	'	'	'	'
Derivative Assets	'	'	6	'
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Commodity Option [Member]	'	'	'	'
Derivative Assets	0	'	0	'
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Equity Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	0	'	0	'
Fair Value, Inputs, Level 3 [Member]	'	'	'	'
Money Market Funds, at Carrying Value	0	'	0	'
Deferred Compensation Plan Assets	0	'	0	'
Assets, Fair Value Disclosure	41	'	151	'
Obligations, Fair Value Disclosure	-8	'	0	'
Fair Value, Inputs, Level 3 [Member] | Auction Rate Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	39	'	36	'
Fair Value, Inputs, Level 3 [Member] | Swap [Member]	'	'	'	'
Derivative Assets	'	'	0	'
Fair Value, Inputs, Level 3 [Member] | Commodity Option [Member]	'	'	'	'
Derivative Assets	10	'	115	'
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]	'	'	'	'
Available-for-sale Securities, Fair Value Disclosure	0	'	0	'
Investments [Member]	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	39	34	36	32
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Investment Income	0	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	4	2	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	-1	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0	'	'
Derivative Financial Instruments, Assets [Member]	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	10	102	115	71
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Investment Income	-8	67	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	-59	100	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	-46	-69	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	0	0	'	'
5.75 %Senior Notes Due 2022 [Member]	'	'	'	'
Debt Instrument, Fair Value Disclosure	768	'	836	'
5.625% Senior Notes Due 2024 [Member]	'	'	'	'
Debt Instrument, Fair Value Disclosure	970	'	1,074	'
7.125% Senior Subordinated Notes due 2018 [Member]	'	'	'	'
Debt Instrument, Fair Value Disclosure	623	'	630	'
6.875% Senior Subordinated Notes due 2020 [Member]	'	'	'	'
Debt Instrument, Fair Value Disclosure	737	'	749	'
Stock Compensation Plan [Member]	'	'	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	'	0	0	'
Liability Value	-8	'	'	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Investment Income	-8	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	-8	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0	'	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net	$0	$0	'	'

Valuation_of_Investments_and_F

Valuation of Investments and Financial Instrument Assets Liabilities By Pricing Levels (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Money market fund investments	$11	$22
Deferred Compensation Plan Assets	8	6
Available-for-sale Securities	39	36
Total	60	190
Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	7	7
Auction Rate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	39	36
Swap [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	'	6
Commodity Option [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	10	115
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Money market fund investments	11	22
Deferred Compensation Plan Assets	8	6
Total	19	33
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	7	7
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Auction Rate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	0	0
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Swap [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	'	0
Quoted Prices In Active Markets for Identical Assets or Liabilities, Fair Value Inputs (Level 1) [Member] | Commodity Option [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	0	0
Significant Other Observable Fair Value Inputs (Level 2) [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Money market fund investments	0	0
Deferred Compensation Plan Assets	0	0
Total	0	6
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	0	0
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Auction Rate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	0	0
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Swap [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	'	6
Significant Other Observable Fair Value Inputs (Level 2) [Member] | Commodity Option [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	0	0
Fair Value, Inputs, Level 3 [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Money market fund investments	0	0
Deferred Compensation Plan Assets	0	0
Total	41	151
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	0	0
Fair Value, Inputs, Level 3 [Member] | Auction Rate Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Available-for-sale Securities	39	36
Fair Value, Inputs, Level 3 [Member] | Swap [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	'	0
Fair Value, Inputs, Level 3 [Member] | Commodity Option [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Oil and gas derivative contracts	$10	$115

Reconciliation_of_Changes_in_F

Reconciliation of Changes in Fair Value of Financial Assets and Liabilities Classified as Level Three In Fair Value Hierarchy (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'
Beginning Balance	$151	$103
Included in earnings	-67	100
Included in other comprehensive income (loss)	4	2
Settlements	-47	-69
Transfers in and out of Level 3	0	0
Ending Balance	41	136
Change in unrealized gains (losses) relating to investments and derivatives still held	-16	67
Derivatives [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'
Beginning Balance	115	71
Included in earnings	-59	100
Included in other comprehensive income (loss)	0	0
Settlements	-46	-69
Transfers in and out of Level 3	0	0
Ending Balance	10	102
Change in unrealized gains (losses) relating to investments and derivatives still held	-8	67
Investments [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'
Beginning Balance	36	32
Included in earnings	0	0
Included in other comprehensive income (loss)	4	2
Settlements	-1	0
Transfers in and out of Level 3	0	0
Ending Balance	39	34
Change in unrealized gains (losses) relating to investments and derivatives still held	$0	$0

Quantitative_Information_about

Quantitative Information about Level 3 Fair Value Measurements (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Stockholder Value Appreciation Program [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Liability Value	-8
Stockholder Value Appreciation Program [Member] | Historical [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
SBC Expected Volatility Rate, Maximum	44.70%
Stockholder Value Appreciation Program [Member] | Implied [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
SBC Expected Volatility Rate, Minimum	37.10%
SBC Expected Volatility Rate, Maximum	39.80%
Natural gas contracts [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Derivative Asset, Fair Value, Total	46
Oil contracts [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Derivative Liability, Fair Value, Total	36
Options Held [Member] | Natural gas contracts [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Derivative Asset, Fair Value, Total	20
Options Held [Member] | Natural gas contracts [Member] | Maximum [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Credit Risk	2.19%
NYMEX Forward Curve Future Price	4.26
Fair Value Assumptions Expected Volatility Curves	32.03%
Options Held [Member] | Natural gas contracts [Member] | Minimum [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Credit Risk	0.01%
NYMEX Forward Curve Future Price	3.49
Fair Value Assumptions Expected Volatility Curves	20.47%
Options Held [Member] | Oil contracts [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Derivative Liability, Fair Value, Total	-10
Options Held [Member] | Oil contracts [Member] | Maximum [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Credit Risk	1.64%
NYMEX Forward Curve Future Price	105
Fair Value Assumptions Expected Volatility Curves	26.34%
Options Held [Member] | Oil contracts [Member] | Minimum [Member]	'
Fair Value, Option, Quantitative Disclosures [Line Items]	'
Credit Risk	0.01%
NYMEX Forward Curve Future Price	87.07
Fair Value Assumptions Expected Volatility Curves	15.48%

Estimated_Fair_Value_of_Notes_

Estimated Fair Value of Notes Based on Quoted Market Prices (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
5.75 %Senior Notes Due 2022 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of debt	$768	$836
5.625% Senior Notes Due 2024 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of debt	970	1,074
7.125% Senior Subordinated Notes due 2018 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of debt	623	630
6.875% Senior Subordinated Notes due 2020 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of debt	$737	$749

Debt_Details

Debt (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]	'	'	'	'	'	'
Line of Credit Facility, Amount Outstanding	$440,000,000	'	$440,000,000	'	'	$0
Long-term debt	3,485,000,000	'	3,485,000,000	'	'	3,045,000,000
Debt issuance costs	'	'	4,000,000	'	'	'
Debt (Textuals)	'	'	'	'	'	'
Line of Credit Facility, Maximum Borrowing Capacity	1,400,000,000	'	1,400,000,000	'	1,250,000,000	'
Largest individual loan commitment by any lender of total commitments	14.00%	'	14.00%	'	'	'
Percentage of basis points to be added for calculation of interest rate	'	'	0.50%	'	'	'
Percent added to prime rate based on grid of our debt rating	'	'	0.75%	'	'	'
Percentage added to LIBOR based on grid of our debt rating	'	'	1.75%	'	'	'
Commitment fee percentage on unused capacity of line of credit	'	'	0.30%	'	'	'
Commitment fees incurred	800,000	900,000	2,500,000	2,500,000	'	'
Ratio of Indebtedness to Net Capital 1	0.6	'	0.6	'	'	'
Ratio of total debt to earnings before gain or loss on disposition of assets, interest expense, income taxes and noncash items	3	'	3	'	'	'
Letters of Credit Outstanding, Amount	70,000,000	'	70,000,000	'	'	'
Issuance fees percentage on letter of credit	'	'	0.20%	'	'	'
Percentage based on a grid of our debt rating on which letters of credit fees are based.	'	'	1.75%	'	'	'
Line of Credit Facility, Current Borrowing Capacity	195,000,000	'	195,000,000	'	'	'
Other Letters of Credit	1,000,000	'	1,000,000	'	'	'
Discount On Notes [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Long-term debt	-5,000,000	'	-5,000,000	'	'	-5,000,000
6.875% Senior Subordinated Notes due 2020 [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Long-term debt	700,000,000	'	700,000,000	'	'	700,000,000
Debt Instrument, Interest Rate, Stated Percentage	6.88%	'	6.88%	'	'	6.88%
7.125% Senior Subordinated Notes due 2018 [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Long-term debt	600,000,000	'	600,000,000	'	'	600,000,000
Debt Instrument, Interest Rate, Stated Percentage	7.13%	'	7.13%	'	'	7.13%
Total senior unsecured debt	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Long-term debt	2,190,000,000	'	2,190,000,000	'	'	1,750,000,000
5.625% Senior Notes Due 2024 [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Long-term debt	1,000,000,000	'	1,000,000,000	'	'	1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.63%	'	5.63%	'	'	5.63%
5.75 %Senior Notes Due 2022 [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Long-term debt	750,000,000	'	750,000,000	'	'	750,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.75%	'	5.75%	'	'	5.75%
Revolving Credit Facility Libor Based Loans [Member]	'	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'	'
Line of Credit Facility, Amount Outstanding	$440,000,000	'	$440,000,000	'	'	$0

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Deferred tax liability:	'	'	'	'	'
Less net current deferred tax liability	$7	'	$7	'	$0
Expected Effective Tax Rate, Minimum	'	'	37.00%	'	'
Expected Effective Tax Rate, Maximum	'	'	38.00%	'	'
Income tax reconciliation to US federal statutory rate	'	'	'	'	'
Amount computed using the statutory rate	-3	-45	43	12	'
Increase (decrease) in taxes resulting from:	'	'	'	'	'
State and local income taxes, net of federal effect	1	-1	4	2	'
Total income tax provision (benefit)	($2)	($46)	$47	$14	'
Income Taxes (Textuals) [Abstract]	'	'	'	'	'
Federal statutory tax rate	'	'	35.00%	'	'
Effective Income Tax Rate Reconciliation, Percent	32.90%	35.80%	38.20%	41.70%	'

StockBased_Compensation_Detail

Stock-Based Compensation (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

1 Months Ended

In Millions, except Share data, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Oct. 25, 2013

Sep. 30, 2013

Equity [Member]

Equity [Member]

Equity [Member]

Equity [Member]

Liability [Member]

Liability [Member]

Liability [Member]

Liability [Member]

Cash-Settled Restricted Stock Units [Member]

Cash-Settled Restricted Stock Units [Member]

Stockholder Value Appreciation Program [Member]

Stockholder Value Appreciation Program [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total stock-based compensation expense

$25

$13

$49

$37

'

$12

$13

$35

$36

$13

$0

$14

$1

'

'

'

'

Capitalized in oil and gas properties

-7

-3

-14

-10

'

'

'

'

'

'

'

'

'

'

'

'

'

Net stock-based compensation expense

18

10

35

27

'

'

'

'

'

'

'

'

'

'

'

'

'

Vesting Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'3 years 0 months 0 days

'

'

'

Number of restricted stock shares vested

'

'

-1,136,000

'

'

'

'

'

'

'

'

'

'

83,000

44,000

'

'

Number of restricted stock shares outstanding

3,701,000

'

3,701,000

'

2,809,000

'

'

'

'

'

'

'

'

1,100,000

'

'

'

Fair value of units vested during the period

'

'

'

'

'

'

'

'

'

'

'

'

'

2

2

'

'

Nonvested Awards, Total Compensation Cost Not yet Recognized

157

'

157

'

'

'

'

'

'

'

'

'

'

23

'

'

35

Weighted Average Volatility Rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

42.00%

Liability Value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8

Liability Settlements

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$13

'

SVAP Price Threshold

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$27.50

SVAP Incremental Price Threshold

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$5

SVAP Expected Term

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'2 years 3 months 0 days

Fair Value Assumptions, Risk Free Interest Rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.41%

Stock-Based Compensation (Textuals) [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition

'

'

'4 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Last reported sales price of our common stock on the New York Stock Exchange per share

$27.37

'

$27.37

'

'

'

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_Stock_

Stock-Based Compensation- Stock Option Activity (Details) (USD $)	9 Months Ended	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Stock option activity	'	'
Outstanding, Beginning Balance, Number of Shares Underlying Options	901	'
Granted, Number of Shares Underlying Options	0	'
Exercised, Number of Shares Underlying Options	-42	'
Forfeited, Number of Shares Underlying Options	-144	'
Outstanding, Ending Balance, Number of Shares Underlying Options	715	901
Exercisable, Number of Shares Underlying Options	715	'
Outstanding, Beginning Balance, Weighted Average Exercise Price per Share	$38.06	'
Granted, Weighted Average Exercise Price per Share	$0	'
Exercised, Weighted Average Exercise Price per Share	$18.10	'
Forfeited, Weighted Average Exercise Price per Share	$37.92	'
Outstanding, Ending Balance, Weighted Average Exercise Price per Share	$39.26	$38.06
Exercisable, Weighted Average Exercise Price per Share	$39.26	'
Weighted average fair value of each option	$0	'
Outstanding, Beginning Balance, Weighted Average Remaining Contractual Life (In years)	'2 years 8 months	'3 years 4 months
Outstanding, Ending Balance, Weighted Average Remaining Contractual Life (In years)	'2 years 8 months	'3 years 4 months
Exercisable, Weighted Average Remaining Contractual Life (In years)	'2 years 8 months	'
Outstanding, Beginning Balance, Aggregate Intrinsic Value	$1	'
Exercised, Aggregate Intrinsic Value	1	'
Outstanding, Ending Balance, Aggregate Intrinsic Value	0	1
Exercisable, Aggregate Intrinsic Value	$0	'

StockBased_Compensation_Stock_1

Stock-Based Compensation- Stock Option Summary (Details) (USD $)	9 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'
Options Outstanding, Number of Shares Underlying Options	715	901
Options Outstanding, Weighted Average Remaining Contractual Life (In years)	'2 years 8 months	'3 years 4 months
Options Exercisable, Number of Shares Underlying Options	715	'
Options Exercisable, Weighted Average Exercise Price per Share	$39.26	'

StockBased_Compensation_Restri

Stock-Based Compensation- Restricted Stock and Restricted Stock Units Activity (Details) (USD $)	9 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Non-vested shares outstanding, Beginning balance	2,809,000
Granted	2,590,000
Forfeited	-562,000
Vested	-1,136,000
Non-vested shares outstanding, Ending balance	3,701,000
Non-vested shares outstanding, Weighted Average Grant Date Fair Value per Share, Beginning balance	$43.31
Granted, Weighted Average Grant Date Fair Value per Share	$27.16
Forfeited, Weighted Average Grant Date Fair Value per Share	$39.46
Vested, Weighted Average Grant Date Fair Value per Share	$39.63
Non-vested shares outstanding, Weighted Average Grant Date Fair Value per Share, Ending balance	$33.72
Service - Based Shares [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Non-vested shares outstanding, Beginning balance	2,371,000
Granted	2,290,000
Forfeited	-540,000
Vested	-1,136,000
Non-vested shares outstanding, Ending balance	2,985,000
Performance Market Based Shares [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Non-vested shares outstanding, Beginning balance	438,000
Granted	300,000
Forfeited	-22,000
Vested	0
Non-vested shares outstanding, Ending balance	716,000

StockBased_Compensation_Employ

Stock-Based Compensation- Employee Stock Purchase Plan (Details) (USD $)	9 Months Ended	3 Months Ended	6 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Jun. 30, 2013
		Employee Stock Purchase Plan [Member]	Employee Stock Purchase Plan [Member]
Employee Stock Purchase Plan ESPP Disclosures [Line Items]	'	'	'
Options To Purchase Common Stock Shares	0	87,000	99,000
Weighted average fair value of each option	$0	$6.20	$6.90
Expected volatility	'	38.00%	40.00%
Risk-free weighted average interest rate	'	0.09%	0.11%
Vesting Period	'	'0 years 6 months 0 days	'0 years 6 months 0 days

Voluntary_Severance_Program_Vo

Voluntary Severance Program Voluntary Severance Program (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Restructuring and Related Activities [Abstract]	'
Severance Costs	$9

Supplemental_Cash_Flows_Inform2

Supplemental Cash Flows Information (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Cash Payments [Abstract]	'	'	'	'
Capitalized interest	$13	$17	$40	$53
Non Cash Items Excluded From Statement of Cash Flows [Abstract]	'	'	'	'
(Increase) decrease in accrued capital expenditures	'	'	-55	-101
Increase in asset retirement costs	'	'	($8)	($14)

Related_Party_Transaction_Deta

Related Party Transaction (Details) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]	'	'	'
Cash purchase price	$6	'	'
Dividends paid to Huffco on preferred shares	$2	$7	$5
Ownership interest percentage in Bohai Bay Unit	12.00%	'	'
Preferred share dividend percentage retained by Huffco	10.00%	'	'

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Oct. 22, 2013
Subsequent Events [Abstract]	'
Subsequent Event Amount To Be Received	$898