Southwestern Energy (SWN) 10-Q 26 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 24, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Entity Registrant Name	SOUTHWESTERN ENERGY CO
Entity Central Index Key	7,332
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		512,425,656
Trading Symbol	SWN

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating Revenues:
Gas sales	$ 394	$ 340	$ 1,368	$ 906
Oil sales	27	19	73	50
NGL sales	55	22	132	59
Marketing	233	237	736	631
Gas gathering	28	33	85	106
Total Operating Revenues	737	651	2,394	1,752
Operating Costs and Expenses:
Marketing purchases	236	234	740	627
Operating expenses	170	139	481	455
General and administrative expenses	62	61	170	171
Restructuring charges		2		77
Depreciation, depletion and amortization	135	99	364	349
Impairment of natural gas and oil properties		817		2,321
Taxes, other than income taxes	24	24	75	69
Total Operating Costs and Expenses	627	1,376	1,830	4,069
Operating Income (Loss)	110	(725)	564	(2,317)
Interest Expense:
Interest on debt	58	59	175	168
Other interest charges	2	8	7	12
Interest capitalized	(29)	(41)	(85)	(123)
Total Interest Expense	31	26	97	57
Gain (Loss) on Derivatives	45	71	295	(28)
Loss on Early Extinguishment of Debt	(59)	(51)	(70)	(51)
Other Income (Loss), Net	(2)	3	6
Income (Loss) Before Income Taxes	63	(728)	698	(2,453)
Benefit for Income Taxes:
Current	(10)		(10)
Deferred	(4)	(20)	(4)	(20)
Benefit for Income Taxes	(14)	(20)	(14)	(20)
Net Income (Loss)	77	(708)	712	(2,433)
Mandatory convertible preferred stock dividend	27	27	81	81
Participating securities - mandatory convertible preferred stock	7		83
Net Income (Loss) Attributable to Common Stock	$ 43	$ (735)	$ 548	$ (2,514)
Earnings (Loss) Per Common Share:
Basic	$ 0.09	$ (1.52)	$ 1.11	$ (6.02)
Diluted	$ 0.09	$ (1.52)	$ 1.10	$ (6.02)
Weighted Average Common Shares Outstanding:
Basic	499,812,926	482,485,150	496,458,435	417,222,661
Diluted	502,290,779	482,485,150	498,527,671	417,222,661

CONDENSED CONSOLIDATED STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)		$ 77	$ (708)	$ 712	$ (2,433)
Change in value of pension and other postretirement liabilities:
Amortization of prior service cost and net loss included in net periodic pension cost	[1]	1	1	2	1
Net gain incurred in period	[1]		1		5
Change in currency translation adjustment					3
Comprehensive income (loss)		$ 78	$ (706)	$ 714	$ (2,424)
[1]	Net of tax for the three and nine months ended September 30, 2017 and 2016.

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 989	$ 1,423
Accounts receivable, net	360	363
Derivative assets	91	51
Other current assets	36	35
Total current assets	1,476	1,872
Natural gas and oil properties, using the full cost method, including $1,919 million as of September 30, 2017 and $2,105 million as of December 31, 2016 excluded from amortization	23,575	22,653
Gathering systems	1,311	1,299
Other	568	537
Less: Accumulated depreciation, depletion and amortization	(19,904)	(19,534)
Total property and equipment, net	5,550	4,955
Other long-term assets	176	249
TOTAL ASSETS	7,202	7,076
Current liabilities:
Short-term debt	40	41
Accounts payable	502	473
Taxes payable	55	59
Interest payable	21	74
Dividends payable	27	27
Derivative liabilities	97	355
Other current liabilities	42	35
Total current liabilities	784	1,064
Long-term debt	4,396	4,612
Pension and other postretirement liabilities	46	49
Other long-term liabilities	324	434
Total long-term liabilities	4,766	5,095
Commitments and contingencies (Note 10)
Equity:
Common stock, $0.01 par value; 1,250,000,000 shares authorized; issued 509,142,659 shares as of September 30, 2017 (does not include 3,346,703 shares issued on October 16, 2017 on account of a dividend declared on September 15, 2017) and 495,248,369 as of December 31, 2016	5	5
Preferred stock, $0.01 par value, 10,000,000 shares authorized, 6.25% Series B Mandatory Convertible, $1,000 per share liquidation preference, 1,725,000 shares issued and outstanding as of September 30, 2017 and December 31, 2016, conversion in January 2018
Additional paid-in capital	4,698	4,677
Accumulated deficit	(3,013)	(3,725)
Accumulated other comprehensive loss	(37)	(39)
Common stock in treasury, 31,269 shares as of September 30, 2017 and December 31, 2016	(1)	(1)
Total equity	1,652	917
TOTAL LIABILITIES AND EQUITY	$ 7,202	$ 7,076

CONDENSED CONSOLIDATED BALANCE5

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Natural gas and oil properties, using the full cost method, costs excluded from amortization	$ 1,919	$ 2,105
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,250,000,000	1,250,000,000
Common stock, shares issued	509,142,659	495,248,369
Common stock, date dividend to be paid	Oct. 16, 2017
Common stock, date dividend declared	Sep. 15, 2017
Treasury stock, shares	31,269	31,269
Series B Preferred Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, dividend rate	6.25%	6.25%
Liquidation preference per share	$ 1,000	$ 1,000
Preferred stock, shares issued	1,725,000	1,725,000
Preferred stock, shares outstanding	1,725,000	1,725,000

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash Flows From Operating Activities:
Net income (loss)	$ 712	$ (2,433)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	364	349
Impairment of natural gas and oil properties		2,321
Amortization of debt issuance costs	7	12
Deferred income taxes	(4)	(20)
(Gain) loss on derivatives, unsettled	(350)	48
Stock-based compensation	19	24
Restructuring charges		30
Loss on early extinguishment of debt	70	51
Other	(2)	5
Change in assets and liabilities:
Accounts receivable	3	53
Accounts payable	16	(72)
Taxes payable	(3)	(17)
Interest payable	(28)	(14)
Other assets and liabilities	(15)
Net cash provided by operating activities	789	337
Cash Flows From Investing Activities:
Capital investments	(943)	(391)
Proceeds from sale of property and equipment	17	434
Other	5
Net cash provided by (used in) investing activities	(921)	43
Cash Flows From Financing Activities:
Payments on short-term debt	(287)	(1)
Payments on long-term debt	(1,139)	(1,175)
Payments on revolving credit facility		(3,268)
Borrowings under revolving credit facility		3,152
Payments on commercial paper		(242)
Borrowings under commercial paper		242
Change in bank drafts outstanding		(19)
Proceeds from issuance of long-term debt	1,150	1,191
Debt issuance costs	(18)	(17)
Proceeds from issuance of common stock		1,247
Preferred stock dividend	(8)	(27)
Other		(4)
Net cash provided by (used in) financing activities	(302)	1,079
Increase (decrease) in cash and cash equivalents	(434)	1,459
Cash and cash equivalents at beginning of year	1,423	15
Cash and cash equivalents at end of period	$ 989	$ 1,474

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - 9 months ended Sep. 30, 2017 - USD ($) $ in Millions		Common Stock [Member]	Preferred Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	[1]	Accumulated Other Comprehensive Income (Loss) [Member]	Common Stock in Treasury [Member]	Total
Balance, shares at Dec. 31, 2016		495,248,369	1,725,000
Balance at Dec. 31, 2016		$ 5		$ 4,677	$ (3,725)		$ (39)	$ (1)	$ 917
Comprehensive income:
Net income					712				712
Other comprehensive income							2		2
Comprehensive income (loss)									714
Stock-based compensation				29					29
Preferred stock dividend, shares	[2]	9,445,013
Preferred stock dividend	[2]			(8)					(8)
Issuance of restricted stock, shares		5,036,122
Cancellation of restricted stock, shares		(609,130)
Performance units vested, shares		121,208
Tax withholding - stock compensation, shares		(98,995)
Issuance of stock awards, shares		72
Balance, shares at Sep. 30, 2017		509,142,659	1,725,000
Balance at Sep. 30, 2017		$ 5		$ 4,698	$ (3,013)		$ (37)	$ (1)	$ 1,652
[1]	Includes a net cumulative-effect adjustment of $59 million related to the recognition of previously unrecognized windfall tax benefits resulting from the adoption of ASU 2016-09 as of the beginning of 2017. This adjustment increased net deferred tax assets and the related income tax valuation allowance by the same amount.
[2]	Does not include 3,346,703 shares issued on October 16, 2017 and distributed to holders of the Company's mandatory convertible preferred stock.

CONDENSED CONSOLIDATED STATEME8

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) - USD ($) $ in Millions	Oct. 16, 2017	Sep. 15, 2017	Sep. 30, 2017
Net cumulative-effect adjustment			$ 59
Common stock, date dividend to be paid		Oct. 16, 2017	Oct. 16, 2017
Subsequent Event [Member]
Common stock, shares issued as stock dividend	3,346,703

Basis Of Presentation

Basis Of Presentation	9 Months Ended
	Sep. 30, 2017
Basis Of Presentation [Abstract]
Basis Of Presentation	(1) BASIS OF PRESEN TATION  Southwestern Energy Company (including its subsidiaries, collectively “Southwestern” or the “Company”) is an independent energy company engaged in natural gas , oil and NGL exploration, development and production (“E&P”). The Company is also focused on creating and capturing additional value through its natural gas gathering and marketing businesses (“Midstream Services”). Southwestern conducts most of its businesses through subsidiaries and operates principally in two segments: E&P and Midstream Services.  The accompanying unaudited condensed consolidated financial statements were prepared using accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and in accordance with the rules and regulations of the Securities and Exchange Commission. Certain information relating to the Company’s organization and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been appropriately condensed or omitted in this Quarterly Report. The Company believes the disclosures made are adequate to make the information presented not misleading.  The unaudited condensed consolidated financial statements contained in this report include all normal and recurring material adjustments that, in the opinion of management, are necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented herein. It is recommended that these unaudited condensed consolidated financial statements be read in conjunction with the consolidated financial statements and the notes thereto included in the Company’s Annual Report for the year ended December 31, 201 6 (“2016 Annual Report”).  The Company’s significant accounting policies, which have been reviewed and approved by the Audit Committee of the Company’s Board of Directors, are summarized in Note 1 in the Notes to the Consolidated Financial Statement s included in the Company’s 2016 Annual Report. 

Cash And Cash Equivalents

Cash And Cash Equivalents	9 Months Ended
	Sep. 30, 2017
Cash And Cash Equivalents [Abstract]
Cash And Cash Equivalents	(2) CASH AND CASH EQUIVALENTS  The following table presents a summary of c ash and cash equivalents as of September 30, 2017 and December 31, 2016 :    September 30 , December 31,  201 7 201 6  (in millions)  Cash $ 259 $ 254  Marketable securities (1) 680 1,169  Other cash equivalents (2) 50 −  Total cash and cash equivalents $ 989 $ 1,423  (1) Consists of government stable value money market funds.  (2) Consists of time deposits. 

Reduction In Workforce

Reduction In Workforce	9 Months Ended
	Sep. 30, 2017
Reduction In Workforce [Abstract]
Reduction In Workforce	(3) REDUC TION IN WORKFORCE  In January 2016, the Company announced a 40% workforce reduction as a result of lower anticipated drilling activity. This reduction was substantially complete d in the first quarter of 2016 . In April 2016, the Company also partially restructured executive management, which was substantially completed in the second quarter of 2016.  The following table presents a summary of the restructuring charges for the three and nine months ended September 30, 2016 :    For the three months ended For the nine months ended  September 30, 2016 September 30, 2016  (in millions)  Severance (including payroll taxes) (1) $ – $ 44  Stock-based compensation (2) – 24  Pension and other postretirement benefits (3) 2 5  Other benefits − 3  Outplacement services, other − 1  Total restructuring charges (4) $ 2 $ 77  (1) Includes $1 million related to executive management restructuring for the nine months ended September 30, 2016.  (2) Includes $3 million related to executive management restructuring for the nine months ended September 30, 2016.  (3) Includes non-cash charges related to the curtailment and settlement of the pension and other postretirement benefit plans. See Note 11 for additional details regarding the Company’s pension and other postretirement benefit plans.  (4) Total restructuring charges were $2 million for the Company’s E&P segment for the three months ended September 30, 2016 . For the nine months ended September 30, 2016, restructuring charges were $74 million and $3 million for the Company’s E&P and Midstream Services segments, respectively.  Severance payments and other separation costs related to restructuring were substantially completed by the end of 2016.

Natural Gas And Oil Properties

Natural Gas And Oil Properties	9 Months Ended
	Sep. 30, 2017
Natural Gas And Oil Properties [Abstract]
Natural Gas And Oil Properties	( 4 ) NATURAL GA S AND OIL PROPERTIES  The Company utilizes the full cost method of accounting for costs related to the exploration, development an d acquisition of natural gas and oil properties. Under this method, all such costs (productive and nonproductive), including salaries, benefits and other internal costs directly attributable to these activities a re capitalized on a country-by- country basis and amortized over the estimated lives of the properties using the units-of-production method. These capitalized costs are subject to a ceiling test that limits such pooled costs , net of applicable deferred taxes, to the aggregate of the present value of future net revenues attributable to proved natural gas , oil and NGL reserves discounted at 10 % (standardized measure) . Any costs in excess of the ceiling are written off as a non-cash expense. The expense may not be reversed in future periods, even though higher natural gas, oil and NGL prices may subsequently increase the ceiling. Companies using the full cost method are required to use the average quoted price from the first day of each month from the previous 12 months, incl uding the impact of derivatives designated for hedge accounting , to calculate the ceiling value of their reserves.  Using the average quoted price from the first day of each month from the previous 12 months for Henry Hub natural gas o f $ 3.00 per MMBtu, West Texas Intermediate oil of $ 46.27 per barrel and NGLs of $ 12.47 p er barrel , adjusted for differentials, the Company’s net book value of its United States natural gas and oil properties did not exceed the ceiling amount and did not result in a ceiling test impairment at September 30 , 201 7 . The Company ha d no h edge positions that were designated for hedge account ing as of September 30 , 201 7 . Decreases in market prices as well as changes in production rates, levels of reserves, evaluation of costs excluded from amortization, future development costs and production costs could result in future ceiling test impairments.  Using the average quoted price from the first day of each month from the previous 12 months for Henry Hub natural gas of $ 2.28 per MMBtu, West Texas Intermediate oil of $ 38.17 per barrel and NGLs of $6.46 per barrel , adjusted for differentials, the net book value of the Company’s United States natura l gas and oil properties result ed in a non-cash ceiling test impairment of $817 million for the three months ended September 30, 2016 . The Company had no hedge positions that were designated for hedge accounting as of September 30, 2016. In the first and second quarters of 2016, the Company recognized non-cash ceiling test impairments of $1,034 million and $470 million, respectively. 

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	( 5 ) EARN INGS PER SHARE  Basic earnings per common share is computed by dividing net income (loss) attributable to common stock by the weighted average number of common shares outstanding during the reportable period. The diluted earnings per share calculation adds to the weighted average number of common shares outstanding: the incremental shares that would have been outstanding assuming the exercise of dilutive stock options, the vesting of unvested restricted shares of common stock , performance units and the assumed conversion of mandatory convertible preferred stock . An antidilutive impact is an increase in earnings per share or a reduction in net loss per share resulting from the conversion, exercise, or contingent issuance of certain securities.  In July 2016, the Company completed an underwritten public offering of 98,900,000 shares of its common stock, with an offering price to the public of $13.00 per share. Net proceeds from the common stock offering were approximately $1,247 million, after underwriting discount and offering expenses. The proceeds from the offering were used to repay $375 million of the $750 million term loan entered into in November 2015 and to settle certain tender offers by purchasing an aggregate principal amount of approximately $700 million of the Company’s outstanding senior notes due in the first quarter of 2018. The remaining proceeds of the offering have been used for general corporate purposes.  The depositary shares issued in January 2015 entitles the holder to a proportional fractional interest in the rights and preferences of the convertible preferred stock, including conversion, dividend, liquidation and voting rights. Unless converted earlier at the option of the holders, on or around January 15, 2018 each share of convertible preferred stock will automatically convert into between 37.0028 and 43.4782 shares of the Company’s common stock ( correspondingly, each depositary share will convert into between 1.85014 and 2.17391 shares of the Company’s common stock), subject to customary anti-dilution adjustments, depending on the volume-weighted average price of the Company’s common stock over a 20 trading day averaging period immediately prior to that date. The total potential shares of common stock resulting from the conversion will range from 63,829,830 to 74,999,895 shares.  The mandatory convertible preferred stock has the non-forfeitable right to participate on an as - converted basis at the conversion rate then in effect in any common stock dividends declared and as such, is considered a participating security. A ccordingly , it is included in the computation of basic and diluted earnings per share, pursuant to the two-class method. In the calculation of basic earnings per share attributable to common shareholders, participating securities are allocated earnings based on actual dividend distributions received plus a proportionate share of undistributed net income attributable to common shareholders, if any, after recognizing distributed earnings. The Company’s participating securities do not participate in undistributed net losses because they are not contractually obligated to do so.  On September 15, 2017 , the Company declared its quarterly dividend, payable to holders of the mandatory convertible preferred stock, and announced that it would pay the quarterly dividend in stock, in lieu of cash, to the extent permitted by the certificate of designations for the Series B preferred stock. The Company i ssued 3,346,703 shares of common stock on October 16, 2017 in partial payment for the dividend, the remaining $7.9 mill ion paid in cash.  The following table presents the computation of earnings per share for the three and nine months ended September 30, 2017 and 2016:        For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions, except share/per share amounts)  Net income (loss) $ 77 $ (708) $ 712 $ (2,433)  Mandatory convertible preferred stock dividend 27 27 81 81  Participating securities - mandatory convertible preferred stock 7 – 83 –  Net income (loss) attributable to common stock $ 43 $ (735) $ 548 $ (2,514)   Number of common shares:  Weighted average outstanding 499,812,926 482,485,150 496,458,435 417,222,661  Issued upon assumed exercise of outstanding stock options – – − –  Effect of issuance of non-vested restricted common stock 1,202,585 – 883,512 –  Effect of issuance of non-vested performance units 1,275,268 – 1,185,724 –  Effect of issuance of mandatory convertible preferred stock – – – –  Weighted average and potential dilutive outstanding 502,290,779 482,485,150 498,527,671 417,222,661   Earnings (l oss) per common share:  Basic $ 0.09 $ (1.52) $ 1.11 $ (6.02)  Diluted $ 0.09 $ (1.52) $ 1.10 $ (6.02)  The following table presents the common stock shares equivalent excluded from the calculation of diluted earnings per share for the three and nine months ended September 30, 2017 and 2016, as they would have had an antidilutive effect:    For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  Unvested stock options 180,932 3,409,596 60,973 3,714,095  Unvested share-based payment 5,703,086 599,372 5,356,166 993,576  Performance units 1,036,422 935,330 1,036,422 762,171  Mandatory convertible preferred stock 74,999,895 74,999,895 74,999,895 74,999,895  Total 81,920,335 79,944,193 81,453,456 80,469,737 

Derivatives And Risk Management

Derivatives And Risk Management	9 Months Ended
	Sep. 30, 2017
Derivatives And Risk Management [Abstract]
Derivatives And Risk Management	(6 ) DERIVATIVES A ND RISK MANAGEMENT  The Company is exposed to volatility in market prices and basis di fferentials for natural gas, oil and NGLs which impacts the predictability of its cash flows related to the sale of those commodities. These risks are managed by the Company’s use of certain derivativ e financial instruments. As of September 3 0, 2017 and December 31, 2016 , the Company’s derivative financial instruments consisted of fixed price swaps, two-way costless collars, three-way costless collars, basis swaps, put and call options, and interest rate swaps. A description of the Company’s derivative financial instruments is provided below:  Fixed price swaps The Company receives a fixed price for the contract and pays a floating market price to the counterparty.  Purchased put options The Company purchases put options based on an index price from the counterparty by payment of a cash premium. If the index price is lower than the put’s strike price at the time of settlement, the Company receives from the counterparty such difference between the index price and the purchased put strike price. If the market price settles above the put’s strike price, no payment is due from either party.  Two-way costless collars Arrangements that contain a fixed floor price (purchased put option) and a fixed ceiling price (sold call option) based on an index price which, in aggregate, have no net cost. At the contract settlement date, (1) if the index price is higher than the ceiling price, the Company pays the counterparty the difference between the index price and ceiling price, (2) if the index price is between the floor and ceiling prices, no payments are due from either party, and (3) if the index price is below the floor price, the Company will receive the difference between the floor price and the index price.  Three-way costless collars Arrangements that contain a purchased put option, a sold call option and a sold put option based on an index price which, in aggregate, have no net cost. At the contract settlement date, (1) if the index price is higher than the sold call strike price, the Company pays the counterparty the difference between the index price and sold call strike price, (2) if the index price is between the purchased put strike price and the sold call strike price, no payments are due from either party, (3) if the index price is between the sold put strike price and the purchased put strike price, the Company will receive the difference between the purchased put strike price and the index price, and (4) if the index price is below the sold put strike price, the Company will receive the difference between the purchased put strike price and the sold put strike price.  Basis swaps Arrangements that guarantee a price differential for natural gas from a specified delivery point. The Company receives a payment from the counterparty if the price differential is greater than the stated terms of the contract and pays the counterparty if the price differential is less than the stated terms of the contract.  Sold call options The Company sells call options in exchange for a premium. I f the market price exceeds the strike price of the call option a t the time of settlement, the Company pays the counterparty such excess on sold call options. If the market price settles below the call’s strike price , no payment is due from either party.  Interest rate swaps Interest rate swaps are used to fix or float interest rates on existing or anticipated indebtedness. The purpose of these instruments is to manage the Company’s existing or anticipated exposure to un favorable interest rate changes.  The Company utilizes counterparties for its derivative instruments that it believes are creditworthy at the time the transactions are entered into , and the Company closely monitors the credit ratings of these counterparties. Additionally, the Company performs both quantitative and qualitative assessments of these counterparties based on their credit ratings and credit default swap rates where applicable. However, there can be no assurance that a counterparty will be able to meet its obligations to the Company.  The following table provides information about the Company’s financial instruments that are sensitive to changes in commodity prices and that are used to protect the Company’s exposure. None of the financial instruments below are designated for hedge accounting treatment. The table presents the notional amount in Bcf, the weighted average contract prices and the fair value by expected maturity dates as of September 30, 2017:       Weighted Average Price per MMBtu  Volume (Bcf) Swaps Sold Puts Purchased Puts Sold Calls Basis Differential Fair Value at September 30, 2017 (in millions)  Financial protection on production  2017  Fixed price swaps 73 $ 3.06 $ – $ – $ – $ – $ 1  Two-way costless-collars 31 – – 2.96 3.38 – 1  Three-way costless-collars 34 – 2.29 2.97 3.30 – –  Total 138 $ 2  2018  Fixed price swaps 178 $ 3.02 $ – $ – $ – $ – $ (4)  Two-way costless-collars 23 – – 2.97 3.56 – (1)  Three-way costless-collars 272 – 2.40 2.97 3.37 – 7  Total 473 $ 2  2019  Three-way costless-collars 108 $ – $ 2.50 $ 2.95 $ 3.32 $ – $ (1)  Total 108 $ (1)   Basis Swaps  2017 32 $ – $ – $ – $ – $ (0.95) $ 12  2018 25 – – – – (0.63) (16)  Total 57 $ (4)     Weighted Average Price per MMBtu  Volume (Bcf) Sold Calls Fair Value at September 30, 2017 (in millions)  Call options  2017 21 $ 3.68 $ – (1)  2018 63 3.50 (9)  2019 52 3.50 (8)  2020 32 3.75 (5)  Total 168 $ (22) (1) Excludes $2 million in premiums paid related to certain call options recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet. As certain call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the unaudited condensed consolidated statement s of operations.  The balance sheet classification of the assets and liabilities related to derivative financial instruments (none of which are designated for hedge accounting treatment) are summarized below as of September 30, 2017 a nd December 31, 2016 :     Derivative Assets  Balance Sheet Classification Fair Value  September 30, 2017 December 31, 2016  (in millions)  Derivatives not designated as hedging instruments:  Fixed price swaps Derivative assets $ 12 $ –  Two-way costless collars Derivative assets 7 8  Three-way costless collars Derivative assets 50 11  Basis swaps Derivative assets 19 32 Call options Derivative assets 1 –  Fixed price swaps Other long-term assets 1 1  Two-way costless collars Other long-term assets – 2  Three-way costless collars Other long-term assets 56 100  Basis swaps Other long-term assets – 1  Total derivative assets $ 146 ( 1 ) $ 155   Derivative Liabilities  Balance Sheet Classification Fair Value  September 30, 2017 December 31, 2016  (in millions)  Derivatives not designated as hedging instruments:  Fixed price swaps Derivative liabilities $ 14 $ 175  Two-way costless collars Derivative liabilities 7 49  Three-way costless collars Derivative liabilities 44 70  Basis swaps Derivative liabilities 23 13  Call options Derivative liabilities 8 46  Interest rate swaps Derivative liabilities 1 2  Fixed price swaps Other long-term liabilities 2 3  Two-way costless collars Other long-term liabilities – 9  Three-way costless collars Other long-term liabilities 56 122  Basis swaps Other long-term liabilities – 5  Call options Other long-term liabilities 15 35  Interest rate swaps Other long-term liabilities 1 1  Total derivative liabilities $ 171 $ 530 (1) Excludes $2 m illion in premiums paid related to certain call options currently recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet. As certain call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the unaudited condensed consolidated statement s of operations.  At September 30, 2017, the net fair value of the Company’s financial instruments related to natural gas was a $23 million liability. The net fair value of the Company’s interest rate swaps was a $2 million liability as of September 30, 2017. The Company had ethane fixed price swaps with an immaterial fair value as of September 30, 2017.  Derivative Contracts Not Designated for Hedge Accounting  As of September 30 , 201 7 , the Company had no positions designated for hedge accounting treatment . G ains and losses on derivatives that are not designated for hedge accounting treatment , or that do not meet hedge accounting requirements , are recorded as a component of gain (loss) on derivatives on the unaudited condensed consolidated statements of operations. Accordingly, the gain (loss) on derivatives component of the statement s of operations reflects the gains and losses on both settled and unsettled derivatives. The Company calculates gains and losses on settled derivatives as the summation of gains and losses on positions which have settled within the reporting period. Only the settled gains and losses are included in the Company’s realized commodity price calculations.  The Company is a party to interest rate swaps that were entered into to mitigate the Company’s exposure to volatility in interest rates. The interest rate swaps have a notional amount of $170 million and expire in June 2020 . The Company did not designate the interest rate swaps for hedge accounting treatment . Changes in the fair value of the interest rate swaps are included in gain (loss) on derivatives o n the unaudited condensed consolidated statements of operations.   The follow ing tables summarize the before- tax effect of fixed price swaps, purchased put options, two-way costless collars, three-way costless collars, basis swaps, call options and interest rate swaps not designated for hedge accounting on the unaudited condensed consolidated statements of operations for the three and nine months ended September 30 , 201 7 and 201 6 :      Gain (Loss) on Derivatives, Unsettled Recognized in Earnings  Consolidated Statements of Operations For the three months ended For the nine months ended  Classification of Gain (Loss) September 30, September 30,  Derivative Instrument on Derivatives, Unsettled 2017 2016 2017 2016  (in millions)  Fixed price swaps (1) Gain (Loss) on Derivatives $ (2) $ 23 $ 174 $ (17)  Two-way costless collars Gain (Loss) on Derivatives 3 5 48 –  Three-way costless collars Gain (Loss) on Derivatives (1) 1 87 (1)  Basis swaps Gain (Loss) on Derivatives 24 31 (19) 27  Call options Gain (Loss) on Derivatives 6 21 59 (54)  Interest rate swaps Gain (Loss) on Derivatives 1 – 1 (3)  Total gain (loss) on unsettled derivatives $ 31 $ 81 $ 350 $ (48)   Gain (Loss) on Derivatives, Settled (2)  Recognized in Earnings  Consolidated Statements of Operations For the three months ended For the nine months ended  Classification of Gain (Loss) September 30, September 30,  Derivative Instrument on Derivatives, Settled 2017 2016 2017 2016  (in millions)  Fixed price swaps (1) Gain (Loss) on Derivatives $ 7 $ (9) $ (18) $ 7 Purchased put options Gain (Loss) on Derivatives – − – 11  Two-way costless collars Gain (Loss) on Derivatives – − (3) −  Three-way costless collars Gain (Loss) on Derivatives 1 − (4) −  Basis swaps Gain (Loss) on Derivatives 9 − (21) 4  Call options Gain (Loss) on Derivatives – − (6) −  Interest rate swaps Gain (Loss) on Derivatives – (1) – (2)  Total gain (loss) on settled derivatives (3) (4) $ 17 $ (10) $ (52) $ 20   Total gain (loss) on derivatives (4) $ 48 $ 71 $ 298 $ (28) (1) Includes the Company’s fixed price swaps on natural gas and ethane. As of September 30, 2017, the amount of unsettled and settled fixed price swaps related to ethane was immaterial. (2) The Company calculates gain (loss) on derivatives, settled, as the summation of gains and losses on positions that have settled within the period. (3) Excluding interest rate swaps and settled ethane fixed price swaps , these amounts are included, along with gas sales revenues, in the calculation of the Company’s realized natural gas price. Settled ethane fixed price swaps are included, along with NGL sales revenues, in the calculation of the Company’s realized NGL price. (4) Excludes $3 million amortization of premiums paid related to certain call options for the three and nine months ended September 30, 2017, which is included in gain (loss) on derivatives on the condensed consolidated statements of operations.  Derivative Contracts Designated for Hedge Accounting  A ll derivatives are recognized in the balance sheet as either an asset or liability and are measured at fair value , other than transactions for which normal purchase/normal sale is applied. Certain criteria must be satisfied in order for derivative financial instruments to be designated for hedge accounting . Unrealized gains and losses related to unsettled derivatives that have been designated for hedge accounting treatment are recorded in either earnings or as a component of other comprehensive income until settled. In the period of settlement, the Company recognizes the gains and losses from these qualifying hedges in gas sales revenues. As of September 30, 2017 and 2016 , the Company had no positions designated for hedge accounting treatment .

Reclassifications From Accumula

Reclassifications From Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2017
Reclassifications From Accumulated Other Comprehensive Income (Loss) [Abstract]
Reclassifications From Accumulated Other Comprehensive Income (Loss)	(7 ) RECL ASSIFICATIONS FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)  The following tables detail the components of accumulated other comprehensive income (loss) and the related tax effects for the nine months ended September 30 , 201 7 :     Pension and Other Postretirement Foreign Currency Total  (in millions)  Beginning balance, December 31, 2016 $ (19) $ (20) $ (39)  Other comprehensive income before reclassifications – – –  Amounts reclassified from other comprehensive income (1) 2 – 2  Net current-period other comprehensive income 2 – 2  Ending balance, September 30, 2017 $ (17) $ (20) $ (37) (1 ) See separate table below for details about these reclassifications . 1        Details about Accumulated Other Comprehensive Income Affected Line Item in the Consolidated Statement of Operations Amount Reclassified from Accumulated Other Comprehensive Income  For the nine months ended September 30, 2017  (in millions)  Pension and other postretirement:  Amortization of prior service cost and net loss (1) General and administrative expenses $ 2  Provision for income taxes –  Net income (loss) $ 2   Total reclassifications for the period Net income (loss) $ 2 (1 ) See Note 11 for additional details regarding the Company’s pension and other postretirement benefit plans. 

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
Fair Value Measurements [Abstract]
Fair Value Measurements	( 8 ) FAIR VALU E MEASUREMENTS  The carrying amounts and estimated fair values of the Company’s financial instruments as of September 30 , 201 7 and December 31, 201 6 were as follows:    September 30, 2017 December 31, 2016  Carrying Fair Carrying Fair  Amount Value Amount Value  (in millions)  Cash and cash equivalents $ 989 $ 989 $ 1,423 $ 1,423  2015 term loan due December 2020 – – 327 327  2016 term loan due December 2020 (1) 1,191 1,191 1,191 1,191  Senior notes 3,282 3,317 3,166 3,182  Derivative instruments, net (2) (25) (25) (375) (375)  (1) The maturity date will accelerate to October 2019 if, by that date, the Company has not amended, redeemed or refinanced at least $765 million of its senior notes due in January 2020. As of September 30 , 2017, the Company has redeemed $758 million principal amount outstanding of the 2020 senior notes. (2) Excludes $2 million in premiums paid related to certain call options currently recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet.  The carrying values of cash and cash equivalents, accounts receivable, other current assets , accounts payable and other current liabilities on the unaudited condensed consolidated balance sheets approxim ate fair value because of their short-term nature. For debt and derivative instruments, the following methods and assumptions were used to estimate fair value:  Debt: The fair values of the Company’s senior notes were based on the market value of the Company’s publicly traded debt as determined based on the yield of the Company’s senior notes.   The carrying values of the borrowings under the Company’s term loan facilities and unsecured revolving credit facility approximate fair value because the interest rate is variable and reflective of market rates. The Company considers the fair value of its debt to be a Level 2 measurement on the fair value hierarchy.  Derivative Instruments: The fair value of all derivative instruments is the amount at which the instrument could be exchanged currently between willing parties. The amounts are based on quoted market prices, best estimates obtained from counterparties and an option pricing model, when necessary, for price option contracts.  The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value. As presented in the tables below, this hierarchy consists of three broad levels:  Level 1 valuations - Consist of unadjusted quoted prices in active markets for identical assets and liabilities and have the highest priority .  Level 2 valuations - Consist of quoted market information for the ca lculation of fair market value.  Level 3 valuations - Consist of internal estimates and have the lowest priority.  The Company has classified its derivatives into these levels depending upon the data utilized to determine their fair values. The Company’s fixed price swaps (Level 2) are estimated using third-party discounted cash flow calculations using the NYMEX futures index. The Company utilized discounted cash flow models for valuing its interest rate derivatives (Level 2). The net derivative val ues attributable to the Company’ s interest rate derivative contracts as of September 30, 2017 are based on (i) the contracted notional amounts, (ii) active market-quoted London Interbank Offered Rate (“LIBOR”) yield curves and (iii) the applicable credit-adjusted risk-free rate yield curve. The Company’s call options, purchased put options, two-way costless collars and three-way costless collars (Level 3) are valued using the Black-Scholes model, an industry standard option valuation model that takes into account inputs such as contract terms, including maturity, and market parameters, including assumptions of the NYMEX futures index, interest rates, volatility and credit worthiness. The Company’s basis swaps (Level 3) are estimated using third-party calculations based upon forward commodity price curves.  Inputs to the Black-Scholes model, including the volatility input, which is the significant unobservable input for Level 3 fair value measurements, are obtained from a third-party pricing source, with independent verification of the most significant inputs on a monthly basis. An increase (decrease) in volatility would result in an increase (decrease) in fair value measurement, respectively.  Assets and liabilities measured at fair value on a recurring basis are summarized below (in millions):      September 30, 2017  Fair Value Measurements Using:  Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value  Fixed price swap assets $ – $ 13 $ – $ 13  Two-way costless collars assets – – 7 7  Three-way costless collars assets – – 106 106  Basis swap assets – – 19 19  Call option assets (1) – – 1 1  Fixed price swap liabilities – (16) – (16)  Two-way costless collars liabilities – – (7) (7)  Three-way costless collars liabilities – – (100) (100)  Basis swap liabilities – – (23) (23)  Call option liabilities – – (23) (23)  Interest rate swap liabilities – (2) – (2)  Total $ – $ (5) $ (20) $ (25) (1) Excludes $2 million in premiums paid related to certain call options currently recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet.    December 31, 2016  Fair Value Measurements Using:  Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value  Fixed price swap assets $ – $ 1 $ – $ 1  Two-way costless collars assets – – 10 10  Three-way costless collars assets – – 111 111  Basis swap assets – – 33 33  Fixed price swap liabilities – (178) – (178)  Two-way costless collars liabilities – – (58) (58)  Three-way costless collars liabilities – – (192) (192)  Basis swap liabilities – – (18) (18)  Call option liabilities – – (81) (81)  Interest rate swap liabilities – (3) – (3)  Total $ – $ (180) $ (195) $ (375)  The table below presents reconciliations for the change in net fair value of derivative assets and liabilities measured at fair value on a recurring basis using significant unobse rvable inputs (Level 3) for the three and nine months ended September 30 , 201 7 and 201 6 . The fair values of Level 3 derivative instruments are estimated using proprietary valuation models that utilize both market observable and unobservable parameters. Level 3 instruments presented in the table consist of net derivatives valued using pricing models incorporating assumptions that, in the Company’s judgment, reflect reasonable assumptions a marketplace partic ipant would have used as of September 30 , 201 7 and 201 6 .             For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions) (in millions)  Balance at beginning of period $ (52) $ (83) $ (195) $ 3  Total gains (losses):  Included in earnings 42 58 141 (13)  Settlements (10) – 34 (15)  Transfers into/out of Level 3 – – – –  Balance at end of period $ (20) $ (25) $ (20) $ (25)  Change in gains (losses) included in earnings relating to derivatives still held as of September 30 $ 32 $ 58 $ 175 $ (28) 

Debt

Debt	9 Months Ended
	Sep. 30, 2017
Debt [Abstract]
Debt	(9) D EBT  The components of debt as of September 30, 2017 and December 31, 2016 consisted of the following:      September 30, 2017  Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total  (in millions)  Short-term debt:  7.35% Senior Notes due October 2017 ( 1 ) $ 15 $ – $ – $ 15  7.125% Senior Notes due October 2017 ( 1 ) 25 – – 25  Total short-term debt $ 40 $ – $ – $ 40   Long-term debt:  Variable rate ( 3.700% at September 30, 2017) 2016 term loan, due December 2020 (2) 1,191 (8) – 1,183  4.05% Senior Notes due January 2020 (3) (4) 92 – – 92  4.10% Senior Notes due March 2022 1,000 (4) – 996  4.95% Senior Notes due January 2025 ( 3 ) 1,000 (6) (2) 992  7.50% Senior Notes due April 2026 650 (10) – 640  7.75% Senior Notes due October 2027 500 (7) – 493  Total long-term debt $ 4,433 $ (35) $ (2) $ 4,396   Total debt $ 4,473 $ (35) $ (2) $ 4,436      December 31, 2016  Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total  (in millions)  Short-term debt:  7.35% Senior Notes due October 2017 ( 1 ) $ 15 $ – $ – $ 15  7.125% Senior Notes due October 2017 ( 1 ) 25 – – 25  7.15% Senior Notes due June 2018 ( 4 ) 1 – – 1  Total short-term debt $ 41 $ – $ – $ 41   Long-term debt:  Variable rate ( 3.220% at December 31, 2016) 2015 term loan, due December 2020 (4) 327 (2) – 325  Variable rate ( 3.220% at December 31, 2016) 2016 term loan, due December 2020 (2) 1,191 (10) – 1,181  3.30% Senior Notes due January 2018 (3) (4) 38 – – 38  7.5 0% Senior Notes due February 2018 (4) 212 – – 212  7.15% Senior Notes due June 2018 ( 4 ) 25 – – 25  4.05% Senior Notes due January 2020 (3) (4) 850 (5) – 845  4.10% Senior Notes due March 2022 1,000 (4) (1) 995  4.95% Senior Notes due January 2025 ( 3 ) 1,000 (7) (2) 991  Total long-term debt $ 4,643 $ (28) $ (3) $ 4,612   Total debt $ 4,684 $ (28) $ (3) $ 4,653 (1) Subsequent to September 30, 2017, the Company repaid $15 million and $25 million of its outstanding 7.35% and 7.125% Senior Notes, respectively, due October 2017. (2) The maturity date will accelerate to October 2019 if, by that date, the Company has not amended, redeemed or refinanced $7 65 million of its outstanding senior notes due in January 2020 . As of September 30, 2017, the Company has redeemed $ 758 million principal amount of the 2020 senior notes. (3) In February and June 2016, Moody’s and S&P downgraded certain senior notes, increasing the interest rates by 175 basis points effective July 2016. As a result of the downgrades, interest rates increased to 5.05% for the 2018 Notes, 5.80% for the 2020 Notes and 6.70% for the 2025 Notes. (4) In the first nine months of 2017, the Company repurchased $38 million principal amount of its outstanding 3.30% Senior Notes due January 2018, $ 212 million principal amount of its outstanding 7.50% Senior Notes due February 2018 , $26 million principal amount of its outstanding 7.15% Senior Notes due June 2018 , $327 million principal amount of its outstanding 2015 Term Loan due December 2020 and $758 million principal amount of its outstanding 4 . 0 5% Senior Notes due J anuary 20 20. The Company recognized a $70 million loss on the extinguishment of debt.  Senior Notes  In January 2015, the Company completed a public offering of $350 million aggregate principal amount of its 3.30% senior notes due 2018 (the “2018 Notes”), $850 million aggregate principal amount of its 4.05% senior notes due 2020 (the “2020 Notes”) and $1.0 billion aggregate principal amount of its 4.95% senior notes due 2025 (the “2025 Notes” together with the 2018 and 2020 Notes, the “Notes” ), with net proceeds from the offering totaling approximately $2.2 billion after underwriting discounts and offering expenses. The interest rates on the Notes are determined based upon the public bond ratings from Moody’s and S&P. Downgrades on the Notes from either rating agency increase interest costs by 25 basis points per downgrade level and upgrades decrease interest costs by 25 basis points per upgrade level, up to the stated coupon rate, on the following semi-annual bond interest payment. In February and June 2016, Moody’s and S&P downgraded the Notes, increasing the interest rates by 175 basis points effective July 2016. As a result of these downgrades, interest rates increased to 5.05% for the 2018 Notes, 5.80% for the 2020 Notes and 6.70% for the 2025 Notes. In the event of future downgrades, the coupons for this series of notes are capped at 5.30% , 6.05% and 6.95% , respectively. The first coupon payment at the higher interest rates was paid in January 2017.  During the first half of 2017, the Company redeemed or repurchased (i) $38 million principal amount of its outstanding 2018 Notes, (ii) $212 million principal amount of its outstanding 7.50% Senior Notes due February 2018 and (iii) $26 million principal amount of its outstanding 7.15% Senior Notes due June 2018 , and recognized a n $11 million loss on the extinguishment of debt. In September 2017, the Company completed a public offering of $650 million aggregate principal amount of its 7.50% senior notes due 2026 (the “2026 Notes”) and $500 million aggregate principal amount of its 7.75% senior notes due 2027 (the “2027 Notes”), with net proceeds from the offering totaling approximately $1.1 billion after underwriting discounts and offering expenses. Both series of senior notes were sold to the public at face value. The proceeds from this offering were used to purchase $ 758 million of the Company’s 2020 Notes in a tender offer and to repay the outstanding balance of $327 million on the Company’s 2015 Term Loan . The Company recognized a loss on extinguishment of debt of $59 million, which included $53 million of premiums paid.  2016 Credit Facility  In June 2016, the Company reduced its existing $2.0 billion unsecured revolving credit facility to $66 million and entered into a new credit agreement for $1,934 million, consisting of a $1,191 million secured term loan and a new $743 million unsecured revolving credit facility, which matures in December 2020 . The maturity date will accelerate to October 2019 if, by that date, the Company has not amended, redeemed or refinanced at least $765 million of its senior notes due January 2020. In September 2017, the Company used a portion of the proceeds from the September 2017 debt offering to settle a tender offer by purchasing an aggregate principal amount of approximately $758 million of its outstanding senior notes due in January 2020 . The $1,191 million secured term loan is fully drawn, with approximately $285 million of this balance used to pay down the previous revolving credit facility bala nce in its entirety. As of September 30, 2017, there were no borrowings under either revolving credit facility; however, $323 million in letters of credit was outstanding against the 2016 revolving credit facility.  Loans under the 2016 credit agreement are subject to varying rates of interest based on whether the loan is a Eurodollar loan or an alternate base rate loan. Eurodollar loans bear interest at the Eurodollar rate, which is adjusted LIBOR plus applicable margins ranging from 1.750% to 2.500% . Alternate base rate loans bear interest at the alternate base rate plus the applicable margin ranging from 0.750% to 1.500% . The interest rate s on the term loan and revolving credit facility are determined based upon the Company’s public debt ratings and was 250 b asis points over LIBOR as of September 30, 2017.  The 2016 term loan and revolving credit facility contain financial covenants that impose certain restrictions on the Company. In September 2017, the Company amended it s 2016 credit agreement to reflect the following:  (i) increase the minimum interest coverage ratio to 2.00x commencing with the fiscal quarter ended June 30, 2017 and continued over the life of the 2016 Credit Agreement;  (ii) modify the minimum liquidity covenant such that either (1) if leverage is less than 4.00x or if the 2016 r evolv ing credit facility has been terminated, there is no minimum liquidity covenant, or (2) the Company can elect to replace the minimum liquidity covenant with a maximum leverage ratio of no more than 5.50x for the fiscal quarters ending September 30, 2017 and December 31, 2017 , 5.00x for the fiscal quarters ending March 31, 2018 and June 30, 2018 and 4.50x thereafter; and  (iii) modify the mandatory prepayment and commitment reduction provisions to permit the Company to retain the first $500.0 million of net cash proceeds from asset sales that would have otherwise been required to prepay amounts outstanding under the 2016 r evolv ing credit facility and/or reduce commitments under the 2016 r evolv ing credit facility.  In September of 2017, substantially all of the proceeds of the 2026 and 2027 notes issuance were applied to repay existing debt .  As of September 30, 2017, the Company has not elected to replace the minimum liquidity covenant with a maximum leverage covenant. Therefore, u nder the amended credit agreement, should the leverage ratio exceed 4.0x , the Company would be subject to a minimum liquidity requirement of $300 million. The financial covenant with respect to the maximum leverage ratio consists of total debt divided by EBITDAX . T he financial covenant with respect to minimum interest coverage consists of EBITDAX divided by consolidated interest expense. EBITDAX, as defined in the Company’s 2016 credit agreement, excludes the effects of interest expense, income taxes, depreciation, depletion and amortization, any non-cash impacts from impairments, certain non-cash hedging activities, stock-based compensation expense, non-cash gains or losses on asset sales, unamortized issuance cost, unamortized debt discount and certain restructuring costs. Collateral for the secured term loan is principally the Company’s E&P properties in the Fayetteville Shale area, the equity of its subsidiaries and cash and marketable securities on hand, and the credit agreement requires a minimum collateral coverage ratio of 1.50x for the 2016 secured term loan. This collateral also may support all or a part of revolving credit extensions depending on restrictions in the Company’s senior notes indentures.  A s of September 30, 2017 , the Company was in compliance with all of the covenants of this credit agreement. Although the Company does not anticipate any violations of the financial covenants, its ability to comply with these covenants is dependent upon the success of its exploration and development program and upon factors beyond the Company’s control, such as the market prices for natural gas, oil and NGLs.  2013 Credit Facility  In December 2013, the Company entered into a credit agreement that exchanged its previous revolving credit facility. Under th is revolving credit facility, the Company originally had a borrowing capacity of $2.0 billion. The revolving credit facility was unsecured and was not guaranteed by any subsidiaries . In June 2016, this credit facility was substantially exchanged for a new credit facility comprised of a $1,191 million secured term loan and a new $743 million revolving credit facility. The borrowing capacity of the original 2013 credit agreement was reduced from $2.0 billion to $66 million, remains unsecured and the maturity remains December 2018 . As of September 30, 2017, there w ere no bo rrowings under this facility.  The existing unsecured 2013 revolving credit facility includes a financial covenant under which the Company may not have total debt in excess of 60% of its total adjusted book capital. This financial covenant with respect to capitalization percentages excludes the effects of any full cost ceiling impairments, certain hedging activities and the Company’s pension and other postretirement liabilities. At September 30, 2017, debt cons tituted 32% of th e Company’s adjusted book capital.  2015 Term Loan  In November 2015, the Company entered into a $750 million unsecured three -year term loan credit agreement with various lenders that was utilized to repay borrowings under the revolving credit facility. In 2016, t he Company repaid $4 23 million of the $750 million unsecured term loan f rom a portion of the net procee ds of the July 2016 equity offering along with proceeds received from a non-core asset sale . In September 2017, the remaining outstanding balance of $327 million was repaid, and the 2015 Term Loan was terminated. 

Commitments And Contingencies

Commitments And Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments And Contingencies [Abstract]
Commitments And Contingencies	(1 0 ) COMMIT MENTS AND CONTINGENCIES  Operating Commitments and Contingencies  As of September 30, 2017, the Company’s contractual obligations for demand and similar charges under firm transportation and gathering agreements to guarantee access capacity on natural gas and liquids pipelines and gathering systems totaled approximate ly $ 8. 9 billion, $3.7 billion of which related to access capacity on future pipeline and gathering infrastructure projects that still require the granting of regulatory approvals and additional construction efforts. Southwestern Energy Company also had guarantee obligations of up to $832 mill ion of that amount. As of September 30 , 201 7 , future payments under non-cancelable firm transportat ion and gathering agreements were as follows:      Payments Due by Period  Total Less than 1 Year 1 to 3 Years 3 to 5 Years 5 to 8 Years More than 8 Years  (in millions)  Infrastructure currently in service $ 5,136 $ 196 $ 1,105 $ 524 $ 1,492 $ 1,819  Pending regulatory approval and/or construction (1) 3,722 432 458 702 114 2,016  Total transportation charges $ 8,858 $ 628 $ 1,563 $ 1,226 $ 1,606 $ 3,835 (1) Based on the estim ated in-service dates as of September 3 0 , 201 7 .  Environ mental Risk  The Company is subject to laws and regulations relating to the protection of the environment. Environmental and cleanup related costs of a non-capital nature are accrued when it is both probable that a liability has been incurred and when the amount can be reasonably estimated. Management believes any future remediation or other compliance related costs will not have a material effect on the financial position or results of operations of the Company.  Litiga tion  The Company is subject to various litigation, claims and proceedings that have arisen in the ordinary course of business, such as for alleged breaches of contract, miscalculation of royalties , employment matters, traffic accidents and pollution, contamination or nuisance. The Company accrues for such items when a liability is both probable and the amount can be reasonably estimated. Management believes that current litigation, claims and proceedings, individually or in aggregate and after taking into account insurance, are not likely to have a material adverse impact on the Company’s financial position, results of operations or cash flows , although it is possible that adverse outcomes could have a material adverse effect on the Company’s results of operations or cash flows for the period in which the effect of that outcome becomes reasonably estimable. Many of these matters are in early stages, so the allegations and the damage theories have not been fully developed, and are all subject to inhe rent uncertainties; therefore, m anagement’s vie w may change in the future.  Arkansas Royalty Litigation  In June 2017 , the jury returned a verdict in favor of the Company on all counts in Smith v. SEECO, Inc. et al. , a class action in the United States District Court for the Eastern District of Arkansas. The plaintiff had alleged that the Company had underpaid lessors of lands in Arkansas by deducting from royalty payments costs for gathering, transportation and compression of natural gas in excess of what is permitted by the relevant leases and asserted claims for, among other things, breach of contract, fraud, civil conspiracy, unjust enrichment and violation of certain Arkansas statutes. Following the verdict, the court entered judgme nt in favor of the Company on all claims. The plaintiff has moved for a new trial, and the court has not yet ruled on that motion.  The plaintiff class in Smith comprises the vast majority of lessors of lands in Arkansas for which leases permit deductions for these types of costs. Most of the remaining lessors are named plaintiffs or members of classes in other pending lawsuits . I n particular, two actions on behalf of certified classes of only Arkansas residents pending in state courts in Arkansas (one is set for trial during the third quarter of 2018; the other does not have a trial date ) and three cases (all currently stayed) that were filed in Arkansas state court on behalf of a total of 248 individually named plaintiffs, two of which have been removed to federal court , have been assigned to the same court that held the Smith trial. Management believes that, as the Smith jury concluded, the deductions from royalty payments were calculated in accordance with the leases. The Company currently does not anticipate that these other cases are likely to have a material adverse effect on the results of operations, financial position or cash flows of the Company.  Indemnifications  The Company provides certain indemnifications in relation to dispositions of assets. These indemnifications typically relate to disputes, litigation or tax matters existing at the date of disposition. No material liabilit ies ha ve been recognized in connection with these indemnifications. 

Pension Plan And Other Postreti

Pension Plan And Other Postretirement Benefits	9 Months Ended
	Sep. 30, 2017
Pension Plan And Other Postretirement Benefits [Abstract]
Pension Plan And Other Postretirement Benefits	(1 1 ) PENSION PLAN AND OTHER POSTRETIREMENT BENEFITS  The Company maintains defined pension and postretirement benefit plans , which cover substantially all of the Company’s employees. Net periodic pension costs include the following components for the three and nine months ended September 30, 2017 and 2016 :    Pension Benefits  For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions)  Service cost $ 2 $ 3 $ 7 $ 9  Interest cost 2 1 4 4  Expected return on plan assets (1) (2) (4) (5)  Amortization of prior service cost – − − −  Amortization of net loss – – 1 1  Curtailment loss − – − 1  Settlement loss − 2 − 10  Net periodic benefit cost $ 3 $ 4 $ 8 $ 20  The Company’s other postretirement benefit plan had a net periodic benefit cost of $1 million for the three months ended September 30 , 2017 and 2016 and a net periodic benefit cost (gain) o f $2 million and ( $4 ) mill ion for the nine months ended September 30, 2017 and 2016, respectively . Included in the net periodic benefit cost for the nine months ended September 30, 2016 is a curtailment gain of $6 million, which more than offset the other components of net periodic benefit cost.  As of September 30 , 201 7 , the Company has contributed $11 mi llion to the pension and other postretirement benefit plans in 2017. The Company expects to contribute an additional $3 mi llion to its pension plan during the remainder of 2017. The Company recognized a liability o f $32 million and $14 million rela ted to its pension and other postretirement be nefits, respectively, as of September 30 , 201 7, compared to a liability of $36 million and $13 million as of December 31, 2016. The Company updated the discount rate currently used in the measurement of the benefit obligation of the pension plan and other postretirement benefits plan to 4.20% in the second quarter of 2016. The Company used a discount rate of 4.60% during the first quarter of 2016 for the measurement of the benefit obligation of both the pension and other postretirement benefit plans. In January 2016, the Company initiated a reduction in workforce that was substantially completed by the end of the first quarter of 2016. The impact of the workforce reduction on the Company’s pension and other postretirement benefit costs was not recognized until subsequent quarters in 2016 due to the delayed timing of actuarial data available.  The Company maintains a non-qualified deferred compensation supplemental retirement savings plan (“Non-Qualified Plan”) for certain key employees who may elect to defer and contribute a portion of their compensation, as permitted by the Non-Qualified P lan. Shares of the Company’s common stock purchased under the terms of the Non-Qualified Plan are presented as treasury stock and tota led 10,652 sh a res at September 30 , 201 7, compared to 31,269 s hares at December 31, 2016 .

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2017
Stock-Based Compensation [Abstract]
Stock-Based Compensation	 (1 2 ) STOCK-BASE D COMPENSATION  The Company recognized the following amounts in employee stock-based compensation costs for the three and nine months ended September 30, 2017 and 201 6 :    For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions)  Stock-based compensation cost – expensed (1) $ 7 $ 6 $ 19 $ 43  Stock-based compensation cost – capitalized $ 2 $ 2 $ 10 $ 7 (1) Includes $16 million and $3 million related to the reduction in workforce and executive management restructuring, respectively, for the nine months ended September 30 , 2016.  In January 2016, the Company announced a 40% workforce reduction that was substantially completed by the end of March 2016. In April 2016, the Company also partially restructured executive management, which was substantially completed in the second quarter of 2016. Affected employees were offered a severance package that included, if applicable, amendments to certain outstanding equity awards that modified forfeiture provisions on separation from the Company. As a result, certain unvested stock-based equity awards became fully vested at the time of separation. These shares were revalued and recognized immediately as a component of restructuring charges on the Company’s unaudited condensed consolidated statements of operations. The unvested portion of equity-based performance units was forfeited upon separation from the Company.  As of September 30, 2017, there w as $ 67 million of total unrecognized compensation cost related to the Company’s unvested stock option grants, restricted stock grants and performance units. This cost is expected to be recognized over a weighted-average period o f 3 years.  Stock Options  The following table summarizes s tock option activity for the nine months ended September 30, 2017 and provides information for options outstanding an d options exercisable as of September 30, 2017 :    Number Weighted Average  of Options Exercise Price  (in thousands) (per share)  Outstanding at December 31, 2016 5,416 $ 23.46  Granted 1,604 8.00  Exercised – –  Forfeited or expired (725) 17.92  Outstanding at September 30, 2017 6,295 20.16  Exercisable at September 30, 2017 3,336 $ 29.37  Restricted Stock  The following table summarizes restr icted stock activity for the nine months ended September 30, 2017 and provides information for unvested shares as of September 30, 2017 :   Number Weighted Average  of Shares Fair Value  (in thousands) (per share)  Unvested shares at December 31, 2016 3,321 $ 11.85  Granted 5,036 8.39  Vested (247) 9.40  Forfeited (609) 10.16  Unvested shares at September 30, 2017 7,501 $ 9.68  Equity-Classified Performance Units  The following table summarizes performance unit activity for the nine months ended September 30, 2017 and provides information for unvested units as o f September 30, 2017. The performance units awarded in 2014 inclu ded a market condition based on r elative Total Shareholder Return (“TSR”) and a performance condition based on the Company's Present Value Index (“PVI”), collectively the “Performance Measures .” The fair value of the TSR market condition is based on a Monte Carlo model and the fair value of the PVI performance condition is based on economic analysis for each investment opportunity based upon the expected present value added for each dollar to be invested. The total fair value of the performance units is amortized to com pensation expense on a straight line basis over the vesting period of the award. The performance unit awards granted in 2015, 2016 and during the first nine months of 2017 include a market condition based exclusively on TSR. The grant date fair value is calculated using the applicable Performance Measures and the closing price of the Company’s common stock at the grant date.     Number Weighted Average  of Units (1) Fair Value  (in thousands) (per share)  Unvested units at December 31, 2016 719 $ 11.46  Granted 1,197 10.47  Vested (42) 5.94  Forfeited (472) 9.74  Unvested units at September 30, 2017 1,402 $ 10.78 (1) These amounts reflect the number of performance units granted in thousands. The actual payout of shares may range from a minimum of zero shares to a maximum of two shares per unit contingent upon the actual performance against the Performance Measures. The performance units have a three -year vesting term and the actual disbursement of shares, if any, is determined during the first quarter following the end of the three-year vesting period.  Liability-Classified Performance Units  Prior to 2013, c ertain employees were award ed performance units which vested equally over three yea rs and which were settled in cash. The payout of these units wa s based on certain metrics, such as total shareholder return and reserve replacement efficiency, compared to a predetermined group of peer companies and Company goal s . At the end of each performance period, the value of the vest ed performance units, if any, would be paid in cash. In the first quarter of 2016, the Company completed the final payout with respect to these performance units .

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2017
Segment Information [Abstract]
Segment Information	(1 3 ) SEGM ENT INFORMATION  The Company’s reportable business segments have been identified based on the differences in products or services provided. Revenues for the E&P segment are derived from the production and sale of natural gas and liquids. The Midstream Services segment generates revenue through the marketing of both Company and third-party produced natural gas and liquids volumes and through gathering fees associated with the transportation of natural gas to market.  Summarized financial information for the Company’s reportable segments is shown in the following table. The accounting policies of the segments are the same as those described in Note 1 of the Notes to Consolidated Financial Statements included in Item 8 of the 201 6 Annual Report. Management evaluates the performance of its segments based on operating income, defined as operating revenues less operating costs. Income before income taxes, for the purpose of reconciling the operating income amount shown below to consolidated income before income taxes, is the sum of oper ating income, interest expense, gain (loss) on derivatives , loss on early extinguishment of debt and other income (loss ). The “Other” column includes items not related to the Company’s reportable segments , including real estate and corporate items.      Exploration and Production Midstream Services Other Total  (in millions)  Three months ended September 30, 2017:  Revenues from external customers $ 475 $ 262 $ – $ 737  Intersegment revenues (5) 472 – 467  Depreciation, depletion and amortization expense 120 15 – 135  Operating income 64 46 – 110  Interest expense (1) 31 – – 31  Gain on derivatives 45 – – 45  Loss on early extinguishment of debt – – (59) (59)  Other income (loss) , net 1 (3) – (2) Benefit for income taxes (1) (14) – – (14)  Assets 4,842 1,240 1,120 (2) 7,202  Capital investments (3) 320 9 2 331   Three months ended September 30, 2016:  Revenues from external customers $ 381 $ 270 $ – $ 651  Intersegment revenues (3) 412 – 409  Depreciation, depletion and amortization expense 83 16 – 99  Impairment of natural gas and oil properties 817 – – 817  Operating income (loss) (777) (4) 52 – (725)  Interest expense (1) 26 – – 26  Gain on derivatives 71 – – 71  Loss on early extinguishment of debt – – (51) (51)  Other income, net 2 1 – 3  Benefit for income taxes (1) (20) – – (20)  Assets 4,015 1,253 1,622 (2) 6,890  Capital investments (3) 179 1 – 180      Exploration and Production Midstream Services Other Total  (in millions)  Nine months ended September 30, 2017:  Revenues from external customers $ 1,572 $ 822 $ – $ 2,394  Intersegment revenues (13) 1,592 – 1,579  Depreciation, depletion and amortization expense 317 47 – 364  Operating income 435 129 – 564  Interest expense (1) 97 – – 97  Gain on derivatives 295 – – 295  Loss on early extinguishment of debt – – (70) (70)  Other income, net 5 1 – 6 Benefit for income taxes (1) (14) – – (14)  Assets 4,842 1,240 1,120 (2) 7,202  Capital investments (3) 921 21 4 946   Nine months ended September 30, 2016:  Revenues from external customers $ 1,015 $ 737 $ – $ 1,752  Intersegment revenues (17) 1,125 – 1,108  Depreciation, depletion and amortization expense 300 49 – 349  Impairment of natural gas and oil properties 2,321 – – 2,321  Operating income (loss) (2,486) (4) 169 (5) – (2,317)  Interest expense (1) 56 1 – 57  Loss on derivatives (27) (1) – (28)  Loss on early extinguishment of debt – – (51) (51)  Other income (loss) , net 3 (2) (1) –  Benefit for income taxes (20) – – (20)  Assets 4,015 1,253 1,622 (2) 6,890  Capital investments (3) 372 3 1 376 (1) Interest expense and the benefit for income taxes by segment are an allocation of corporate amounts as they are incurred at the corporate level. (2) Other assets represent corporate assets not allocated to segments and assets for non-reportable segments. At September 30, 2017 and 2016, other assets includes approximately $989 m illion and $1.5 b illion in cash and cash equivalents, respectively. (3) Capital investments includes a decre ase of $2 million and an increase of $27 million for the three months ended September 30, 2017 and 2016 , respectively, and decreases of $13 million and $24 million for the nine months ended September 30, 2017 and 2016, respectively, relating to the change in capital accruals between periods. (4) Operating income (loss) for the E&P segment includes $2 million and $74 million related to restructuring charges for the three and nine months ended September 30, 2016, respectively. (5) Operating income (loss) for the Midstream services segment includes $3 million related to restructuring charges for the nine months ended September 30, 2016.  Included in intersegment revenues of the Midstrea m Services segment are $ 422 million and $ 355 million for the three months ended September 30, 2017 and 2016, respectively and $1,436 million and $941 million for the nine months ended September 30, 2017 and 2016, respectively, for marketing of the Company’s E&P sales. Corp orate assets include cash and cash equivalents, furniture and fixtures and other costs. Corporate general and administrative costs, depreciation expense and taxes other than income are allocated to the segments.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Taxes [Abstract]
Income Taxes	(14) INCOME TAXES  The Company’s effective tax rate was approximatel y (21%) and (2%) for th e three and nine months ended September 30, 2017 , respectively, and 3% and 1% for the same periods in 2016, respectively. The income tax benefits recognized in the third quarter of 2017 resulted from an expected alternative minimum tax refund along with the expiration of a portion of the Company’s uncertain tax provision. The low effective tax rates are primarily a result of the existence of a valuation allowance. A valuation allowance for deferred tax assets, including net operating losses, is recognized when it is more likely than not that some or all of the benefit from the deferred tax asset s will not be realized. To assess that likelihood, the Company uses estimates and judgment regarding future taxable income, and considers the tax consequences in the jurisdiction where such taxable income is generated, to determine whether a valuation allowance is required. Such evidence can include current financial position, results of operations, both actual and forecasted, the reversal of deferred tax liabilities, and tax planning strategies as well as the current and forecasted business economics of the oil and gas industry.  The Company maintained its net deferred tax asset position at September 30, 2017 primarily due to the write-downs of the carrying value of natural gas and oil properties in 2015 and 2016. The Company recorded decreases in our valuation allowance of $38 million and $220 million for the three and nine months ended September 30, 2017 , respectively. For the three and nine months ended September 30, 2016, there were increases in our valuation allowance of $256 million and $903 million, respectively . Management assesses the available positive and negative evidence to estimate whether sufficient future taxable income will be generated to permit the use of deferred tax assets. In management’s view, the cumulative loss incurred over recent years outweighs any positive factors, such as the possibility of future growth. The amount of the deferred tax asset s considered realizable, however, could be adjusted if estimates of future taxable income are increased or if objective negative evidence in the form of cumulative losses is no longer present and additional weight is given to subjective evidence such as future expected growth. 

New Accounting Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements [Abstract]
New Accounting Pronouncements	(1 5 ) NEW ACCOUNTI NG PRONOUNCEMENTS  New Accounting Standards Implemented  In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2016-09, Compensation – Stock Compensation (Topic 718) (“Update 2016-09”), to simplify accounting for share-based payment transactions including income tax consequences, classification of awards as either equity or liabilities, and the classification on the statement of cash flows. For public entities, Update 2016-09 became effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years, with early adoption permitted. The Company adopted Update 2016-09 during the first quarter with an effective date of January 1, 2017. The recognition of previously unrecognized windfall tax benefits resulted in a net cumulative-effect adjustment of $59 million, which increased net deferred tax assets and the related income tax valuation allowance by the same amount as of the beginning of 2017. The amendments within Update 2016-09 related to the recognition of excess tax benefits and tax shortfalls in the income statement and presentation within the operating section of the statement of cash flows were adopted prospectively, with no adjustments made to prior periods. The Company has elected to account for forfeitures as they occur. The remaining provisions of this amendment did not have a material effect on its unaudited condensed consolidated results of operations, financial position or cash flows.  New Accounting Standards Not Yet Implemented  In August 2017, the FASB issued Accounting Standards Update (ASU) No. 2017-12, Derivatives and Hedging (Topic 815) (“Update 2017-12”), which makes significant changes to the current hedge accounting rules. The new guidance impacts the designation of hedging relationships; measurement of hedging relationships; presentation of the effects of hedging relationships; assessment of hedge effectiveness; and disclosures. The guidance is effective for annual periods beginning after December 15, 2018, including interim periods within those annual periods. The Company is evaluating the impact of the adoption of Update 2017-12 on its consolidated financial statements and related disclosures.  In March 2017, the FASB issued Accounting Standards Update No. 2017-07, Compensation - Retirement Benefits (Topic 715) (“Update 2017-07”), which provides additional guidance on the presentation of net benefit cost in the statement of operations and on the components eligible for capitalization in assets. The guidance requires employers to disaggregate the service cost component from the other components of net benefit cost. The service cost component of the net periodic benefit cost shall be reported in the same line item as other compensation costs arising from services rendered by the employees during the period, except for amounts capitalized. All other components of net benefit cost shall be presented outside of a subtotal for income from operations. The guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. The amendments in this update should be applied retrospectively for the presentation of the service cost component and the other components of net periodic postretirement benefit cost in the income statement and prospectively, on and after the effective date, for the capitalization of the service cost component of net periodic benefit cost in assets. The Company does not expect the impact of adopting Update 2017-07 to have a material effect on its consolidated financial statements and related disclosures.  In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Statement of Cash Flows (Topic 230) (“Update 2016-15”), which seeks to reduce the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. For public entities, Update 2016-15 becomes effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, with early adoption permitted. The Company does not expect the impact of adopting Update 2016-15 to have a material effect on its consolidated financial statements and related disclosures .  In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) (“Update 2016-02”), which seeks to increase transparency and comparability among organizations by, among other things, recognizing lease assets and lease liabilities on the balance sheet for leases classified as operating leases under previous GAAP and disclosing key information about leasing arrangements. Through September 2017, the Company made progress on contract reviews, drafting its accounting policies, evaluating lease accounting software and assessing the new disclosure requirements. The Company will continue assessing the effect that the updated standard may have on its consolidated financial statements and related disclosures, and anticipates that its assessment will be complete in 2018. For public entities, Update 2016-02 becomes effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption permitted.  In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“Update 2014-09”), which seeks to provide clarity for recognizing revenue. The new standard removes inconsistencies in existing standards, changes the way companies recognize revenue from contracts with customers and increases disclosure requirements. The codification was amended through additional ASUs and, as amended, requires an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the entity expects to be entitled to in exchange for those goods or services. The Company performed an analysis, across all revenue streams, of the impact of Update 2014-09 and the related ASUs and did not , to date, identify any changes to its revenue recognition policies that would result in a material adjustment to its consolidated financial statements and related disclosures . The Company will continue to conduct its contract review process throughout 2017 and, as a result, additional areas of impact may be identified. The Company expects to adopt the new standard using the modified retrospective approach, under which the cumulative effect of initially applying the new guidance is recognized as an adjustment to the opening balance of retained earnings in the first quarter of 2018. For public entities, the new standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period.

Cash And Cash Equivalents (Tabl

Cash And Cash Equivalents (Tables)	9 Months Ended
	Sep. 30, 2017
Cash And Cash Equivalents [Abstract]
Summary Of Cash And Cash Equivalents	   September 30 , December 31,  201 7 201 6  (in millions)  Cash $ 259 $ 254  Marketable securities (1) 680 1,169  Other cash equivalents (2) 50 −  Total cash and cash equivalents $ 989 $ 1,423  (1) Consists of government stable value money market funds.  (2) Consists of time deposits.

Reduction In Workforce (Tables)

Reduction In Workforce (Tables)	9 Months Ended
	Sep. 30, 2017
Reduction In Workforce [Abstract]
Summary Of Restructuring Charges	  For the three months ended For the nine months ended  September 30, 2016 September 30, 2016  (in millions)  Severance (including payroll taxes) (1) $ – $ 44  Stock-based compensation (2) – 24  Pension and other postretirement benefits (3) 2 5  Other benefits − 3  Outplacement services, other − 1  Total restructuring charges (4) $ 2 $ 77  (1) Includes $1 million related to executive management restructuring for the nine months ended September 30, 2016.  (2) Includes $3 million related to executive management restructuring for the nine months ended September 30, 2016.  (3) Includes non-cash charges related to the curtailment and settlement of the pension and other postretirement benefit plans. See Note 11 for additional details regarding the Company’s pension and other postretirement benefit plans.  (4) Total restructuring charges were $2 million for the Company’s E&P segment for the three months ended September 30, 2016 . For the nine months ended September 30, 2016, restructuring charges were $74 million and $3 million for the Company’s E&P and Midstream Services segments, respectively.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share	  For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions, except share/per share amounts)  Net income (loss) $ 77 $ (708) $ 712 $ (2,433)  Mandatory convertible preferred stock dividend 27 27 81 81  Participating securities - mandatory convertible preferred stock 7 – 83 –  Net income (loss) attributable to common stock $ 43 $ (735) $ 548 $ (2,514)   Number of common shares:  Weighted average outstanding 499,812,926 482,485,150 496,458,435 417,222,661  Issued upon assumed exercise of outstanding stock options – – − –  Effect of issuance of non-vested restricted common stock 1,202,585 – 883,512 –  Effect of issuance of non-vested performance units 1,275,268 – 1,185,724 –  Effect of issuance of mandatory convertible preferred stock – – – –  Weighted average and potential dilutive outstanding 502,290,779 482,485,150 498,527,671 417,222,661   Earnings (l oss) per common share:  Basic $ 0.09 $ (1.52) $ 1.11 $ (6.02)  Diluted $ 0.09 $ (1.52) $ 1.10 $ (6.02) 
Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share	  For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  Unvested stock options 180,932 3,409,596 60,973 3,714,095  Unvested share-based payment 5,703,086 599,372 5,356,166 993,576  Performance units 1,036,422 935,330 1,036,422 762,171  Mandatory convertible preferred stock 74,999,895 74,999,895 74,999,895 74,999,895  Total 81,920,335 79,944,193 81,453,456 80,469,737 

Derivatives And Risk Manageme27

Derivatives And Risk Management (Tables)	9 Months Ended
	Sep. 30, 2017
Derivatives And Risk Management [Abstract]
Schedule Of Derivative Instruments, Notional Amount In BCF, Weighted Average Contract Prices And Fair Value	  Weighted Average Price per MMBtu  Volume (Bcf) Swaps Sold Puts Purchased Puts Sold Calls Basis Differential Fair Value at September 30, 2017 (in millions)  Financial protection on production  2017  Fixed price swaps 73 $ 3.06 $ – $ – $ – $ – $ 1  Two-way costless-collars 31 – – 2.96 3.38 – 1  Three-way costless-collars 34 – 2.29 2.97 3.30 – –  Total 138 $ 2  2018  Fixed price swaps 178 $ 3.02 $ – $ – $ – $ – $ (4)  Two-way costless-collars 23 – – 2.97 3.56 – (1)  Three-way costless-collars 272 – 2.40 2.97 3.37 – 7  Total 473 $ 2  2019  Three-way costless-collars 108 $ – $ 2.50 $ 2.95 $ 3.32 $ – $ (1)  Total 108 $ (1)   Basis Swaps  2017 32 $ – $ – $ – $ – $ (0.95) $ 12  2018 25 – – – – (0.63) (16)  Total 57 $ (4)     Weighted Average Price per MMBtu  Volume (Bcf) Sold Calls Fair Value at September 30, 2017 (in millions)  Call options  2017 21 $ 3.68 $ – (1)  2018 63 3.50 (9)  2019 52 3.50 (8)  2020 32 3.75 (5)  Total 168 $ (22) (1) Excludes $2 million in premiums paid related to certain call options recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet. As certain call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the unaudited condensed consolidated statement s of operations.
Balance Sheet Classification Of Derivative Financial Instruments	  Derivative Assets  Balance Sheet Classification Fair Value  September 30, 2017 December 31, 2016  (in millions)  Derivatives not designated as hedging instruments:  Fixed price swaps Derivative assets $ 12 $ –  Two-way costless collars Derivative assets 7 8  Three-way costless collars Derivative assets 50 11  Basis swaps Derivative assets 19 32 Call options Derivative assets 1 –  Fixed price swaps Other long-term assets 1 1  Two-way costless collars Other long-term assets – 2  Three-way costless collars Other long-term assets 56 100  Basis swaps Other long-term assets – 1  Total derivative assets $ 146 ( 1 ) $ 155   Derivative Liabilities  Balance Sheet Classification Fair Value  September 30, 2017 December 31, 2016  (in millions)  Derivatives not designated as hedging instruments:  Fixed price swaps Derivative liabilities $ 14 $ 175  Two-way costless collars Derivative liabilities 7 49  Three-way costless collars Derivative liabilities 44 70  Basis swaps Derivative liabilities 23 13  Call options Derivative liabilities 8 46  Interest rate swaps Derivative liabilities 1 2  Fixed price swaps Other long-term liabilities 2 3  Two-way costless collars Other long-term liabilities – 9  Three-way costless collars Other long-term liabilities 56 122  Basis swaps Other long-term liabilities – 5  Call options Other long-term liabilities 15 35  Interest rate swaps Other long-term liabilities 1 1  Total derivative liabilities $ 171 $ 530 (1) Excludes $2 m illion in premiums paid related to certain call options currently recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet. As certain call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the unaudited condensed consolidated statement s of operations.
Summary Of Before Tax Effect Of Fair Value Hedges Not Designated For Hedge Accounting	    Gain (Loss) on Derivatives, Unsettled Recognized in Earnings  Consolidated Statements of Operations For the three months ended For the nine months ended  Classification of Gain (Loss) September 30, September 30,  Derivative Instrument on Derivatives, Unsettled 2017 2016 2017 2016  (in millions)  Fixed price swaps (1) Gain (Loss) on Derivatives $ (2) $ 23 $ 174 $ (17)  Two-way costless collars Gain (Loss) on Derivatives 3 5 48 –  Three-way costless collars Gain (Loss) on Derivatives (1) 1 87 (1)  Basis swaps Gain (Loss) on Derivatives 24 31 (19) 27  Call options Gain (Loss) on Derivatives 6 21 59 (54)  Interest rate swaps Gain (Loss) on Derivatives 1 – 1 (3)  Total gain (loss) on unsettled derivatives $ 31 $ 81 $ 350 $ (48)   Gain (Loss) on Derivatives, Settled (2)  Recognized in Earnings  Consolidated Statements of Operations For the three months ended For the nine months ended  Classification of Gain (Loss) September 30, September 30,  Derivative Instrument on Derivatives, Settled 2017 2016 2017 2016  (in millions)  Fixed price swaps (1) Gain (Loss) on Derivatives $ 7 $ (9) $ (18) $ 7 Purchased put options Gain (Loss) on Derivatives – − – 11  Two-way costless collars Gain (Loss) on Derivatives – − (3) −  Three-way costless collars Gain (Loss) on Derivatives 1 − (4) −  Basis swaps Gain (Loss) on Derivatives 9 − (21) 4  Call options Gain (Loss) on Derivatives – − (6) −  Interest rate swaps Gain (Loss) on Derivatives – (1) – (2)  Total gain (loss) on settled derivatives (3) (4) $ 17 $ (10) $ (52) $ 20   Total gain (loss) on derivatives (4) $ 48 $ 71 $ 298 $ (28) (1) Includes the Company’s fixed price swaps on natural gas and ethane. As of September 30, 2017, the amount of unsettled and settled fixed price swaps related to ethane was immaterial. (2) The Company calculates gain (loss) on derivatives, settled, as the summation of gains and losses on positions that have settled within the period. (3) Excluding interest rate swaps and settled ethane fixed price swaps , these amounts are included, along with gas sales revenues, in the calculation of the Company’s realized natural gas price. Settled ethane fixed price swaps are included, along with NGL sales revenues, in the calculation of the Company’s realized NGL price. (4) Excludes $3 million amortization of premiums paid related to certain call options for the three and nine months ended September 30, 2017, which is included in gain (loss) on derivatives on the condensed consolidated statements of operations.

Reclassifications From Accumu28

Reclassifications From Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2017
Reclassifications From Accumulated Other Comprehensive Income (Loss) [Abstract]
Components Of Accumulated Other Comprehensive Income (Loss)	   Pension and Other Postretirement Foreign Currency Total  (in millions)  Beginning balance, December 31, 2016 $ (19) $ (20) $ (39)  Other comprehensive income before reclassifications – – –  Amounts reclassified from other comprehensive income (1) 2 – 2  Net current-period other comprehensive income 2 – 2  Ending balance, September 30, 2017 $ (17) $ (20) $ (37) (1 ) See separate table below for details about these reclassifications .
Amounts Reclassified From Accumulated Other Comprehensive Income (Loss)	     Details about Accumulated Other Comprehensive Income Affected Line Item in the Consolidated Statement of Operations Amount Reclassified from Accumulated Other Comprehensive Income  For the nine months ended September 30, 2017  (in millions)  Pension and other postretirement:  Amortization of prior service cost and net loss (1) General and administrative expenses $ 2  Provision for income taxes –  Net income (loss) $ 2   Total reclassifications for the period Net income (loss) $ 2 (1 ) See Note 11 for additional details regarding the Company’s pension and other postretirement benefit plans.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Measurements [Abstract]
Carrying Amount And Estimated Fair Values Of Financial Instruments	  September 30, 2017 December 31, 2016  Carrying Fair Carrying Fair  Amount Value Amount Value  (in millions)  Cash and cash equivalents $ 989 $ 989 $ 1,423 $ 1,423  2015 term loan due December 2020 – – 327 327  2016 term loan due December 2020 (1) 1,191 1,191 1,191 1,191  Senior notes 3,282 3,317 3,166 3,182  Derivative instruments, net (2) (25) (25) (375) (375)  (1) The maturity date will accelerate to October 2019 if, by that date, the Company has not amended, redeemed or refinanced at least $765 million of its senior notes due in January 2020. As of September 30 , 2017, the Company has redeemed $758 million principal amount outstanding of the 2020 senior notes. (2) Excludes $2 million in premiums paid related to certain call options currently recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet.
Summary Of Assets And Liabilities Measured At Fair Value On Recurring Basis	   September 30, 2017  Fair Value Measurements Using:  Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value  Fixed price swap assets $ – $ 13 $ – $ 13  Two-way costless collars assets – – 7 7  Three-way costless collars assets – – 106 106  Basis swap assets – – 19 19  Call option assets (1) – – 1 1  Fixed price swap liabilities – (16) – (16)  Two-way costless collars liabilities – – (7) (7)  Three-way costless collars liabilities – – (100) (100)  Basis swap liabilities – – (23) (23)  Call option liabilities – – (23) (23)  Interest rate swap liabilities – (2) – (2)  Total $ – $ (5) $ (20) $ (25) (1) Excludes $2 million in premiums paid related to certain call options currently recognized as a component of derivative assets within current assets on the unaudited condensed consolidated balance sheet.    December 31, 2016  Fair Value Measurements Using:  Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value  Fixed price swap assets $ – $ 1 $ – $ 1  Two-way costless collars assets – – 10 10  Three-way costless collars assets – – 111 111  Basis swap assets – – 33 33  Fixed price swap liabilities – (178) – (178)  Two-way costless collars liabilities – – (58) (58)  Three-way costless collars liabilities – – (192) (192)  Basis swap liabilities – – (18) (18)  Call option liabilities – – (81) (81)  Interest rate swap liabilities – (3) – (3)  Total $ – $ (180) $ (195) $ (375) 
Reconciliations For Change In Net Fair Value Of Derivative Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Significant Unobservable Inputs (Level 3)	  For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions) (in millions)  Balance at beginning of period $ (52) $ (83) $ (195) $ 3  Total gains (losses):  Included in earnings 42 58 141 (13)  Settlements (10) – 34 (15)  Transfers into/out of Level 3 – – – –  Balance at end of period $ (20) $ (25) $ (20) $ (25)  Change in gains (losses) included in earnings relating to derivatives still held as of September 30 $ 32 $ 58 $ 175 $ (28) 

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt [Abstract]
Components Of Debt	  September 30, 2017  Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total  (in millions)  Short-term debt:  7.35% Senior Notes due October 2017 ( 1 ) $ 15 $ – $ – $ 15  7.125% Senior Notes due October 2017 ( 1 ) 25 – – 25  Total short-term debt $ 40 $ – $ – $ 40   Long-term debt:  Variable rate ( 3.700% at September 30, 2017) 2016 term loan, due December 2020 (2) 1,191 (8) – 1,183  4.05% Senior Notes due January 2020 (3) (4) 92 – – 92  4.10% Senior Notes due March 2022 1,000 (4) – 996  4.95% Senior Notes due January 2025 ( 3 ) 1,000 (6) (2) 992  7.50% Senior Notes due April 2026 650 (10) – 640  7.75% Senior Notes due October 2027 500 (7) – 493  Total long-term debt $ 4,433 $ (35) $ (2) $ 4,396   Total debt $ 4,473 $ (35) $ (2) $ 4,436      December 31, 2016  Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total  (in millions)  Short-term debt:  7.35% Senior Notes due October 2017 ( 1 ) $ 15 $ – $ – $ 15  7.125% Senior Notes due October 2017 ( 1 ) 25 – – 25  7.15% Senior Notes due June 2018 ( 4 ) 1 – – 1  Total short-term debt $ 41 $ – $ – $ 41   Long-term debt:  Variable rate ( 3.220% at December 31, 2016) 2015 term loan, due December 2020 (4) 327 (2) – 325  Variable rate ( 3.220% at December 31, 2016) 2016 term loan, due December 2020 (2) 1,191 (10) – 1,181  3.30% Senior Notes due January 2018 (3) (4) 38 – – 38  7.5 0% Senior Notes due February 2018 (4) 212 – – 212  7.15% Senior Notes due June 2018 ( 4 ) 25 – – 25  4.05% Senior Notes due January 2020 (3) (4) 850 (5) – 845  4.10% Senior Notes due March 2022 1,000 (4) (1) 995  4.95% Senior Notes due January 2025 ( 3 ) 1,000 (7) (2) 991  Total long-term debt $ 4,643 $ (28) $ (3) $ 4,612   Total debt $ 4,684 $ (28) $ (3) $ 4,653 (1) Subsequent to September 30, 2017, the Company repaid $15 million and $25 million of its outstanding 7.35% and 7.125% Senior Notes, respectively, due October 2017. (2) The maturity date will accelerate to October 2019 if, by that date, the Company has not amended, redeemed or refinanced $7 65 million of its outstanding senior notes due in January 2020 . As of September 30, 2017, the Company has redeemed $ 758 million principal amount of the 2020 senior notes. (3) In February and June 2016, Moody’s and S&P downgraded certain senior notes, increasing the interest rates by 175 basis points effective July 2016. As a result of the downgrades, interest rates increased to 5.05% for the 2018 Notes, 5.80% for the 2020 Notes and 6.70% for the 2025 Notes. (4) In the first nine months of 2017, the Company repurchased $38 million principal amount of its outstanding 3.30% Senior Notes due January 2018, $ 212 million principal amount of its outstanding 7.50% Senior Notes due February 2018 , $26 million principal amount of its outstanding 7.15% Senior Notes due June 2018 , $327 million principal amount of its outstanding 2015 Term Loan due December 2020 and $758 million principal amount of its outstanding 4 . 0 5% Senior Notes due J anuary 20 20. The Company recognized a $70 million loss on the extinguishment of debt.

Commitments And Contingencies (

Commitments And Contingencies (Tables)	9 Months Ended
	Sep. 30, 2017
Commitments And Contingencies [Abstract]
Schedule Of Future Obligation Under Transportation Agreements	  Payments Due by Period  Total Less than 1 Year 1 to 3 Years 3 to 5 Years 5 to 8 Years More than 8 Years  (in millions)  Infrastructure currently in service $ 5,136 $ 196 $ 1,105 $ 524 $ 1,492 $ 1,819  Pending regulatory approval and/or construction (1) 3,722 432 458 702 114 2,016  Total transportation charges $ 8,858 $ 628 $ 1,563 $ 1,226 $ 1,606 $ 3,835 (1) Based on the estim ated in-service dates as of September 3 0 , 201 7 .

Pension Plan And Other Postre32

Pension Plan And Other Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2017
Pension Plan And Other Postretirement Benefits [Abstract]
Pension And Other Postretirement Benefit Costs	  Pension Benefits  For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions)  Service cost $ 2 $ 3 $ 7 $ 9  Interest cost 2 1 4 4  Expected return on plan assets (1) (2) (4) (5)  Amortization of prior service cost – − − −  Amortization of net loss – – 1 1  Curtailment loss − – − 1  Settlement loss − 2 − 10  Net periodic benefit cost $ 3 $ 4 $ 8 $ 20 

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
Stock-Based Compensation [Abstract]
Schedule Of Stock-Based Compensation Costs	  For the three months ended For the nine months ended  September 30, September 30,  2017 2016 2017 2016  (in millions)  Stock-based compensation cost – expensed (1) $ 7 $ 6 $ 19 $ 43  Stock-based compensation cost – capitalized $ 2 $ 2 $ 10 $ 7 (1) Includes $16 million and $3 million related to the reduction in workforce and executive management restructuring, respectively, for the nine months ended September 30 , 2016.
Summary Of Stock Option Activity	  Number Weighted Average  of Options Exercise Price  (in thousands) (per share)  Outstanding at December 31, 2016 5,416 $ 23.46  Granted 1,604 8.00  Exercised – –  Forfeited or expired (725) 17.92  Outstanding at September 30, 2017 6,295 20.16  Exercisable at September 30, 2017 3,336 $ 29.37 
Summary Of Restricted Stock Activity	  Number Weighted Average  of Shares Fair Value  (in thousands) (per share)  Unvested shares at December 31, 2016 3,321 $ 11.85  Granted 5,036 8.39  Vested (247) 9.40  Forfeited (609) 10.16  Unvested shares at September 30, 2017 7,501 $ 9.68 
Summary Of Performance Unit Activity	  Number Weighted Average  of Units (1) Fair Value  (in thousands) (per share)  Unvested units at December 31, 2016 719 $ 11.46  Granted 1,197 10.47  Vested (42) 5.94  Forfeited (472) 9.74  Unvested units at September 30, 2017 1,402 $ 10.78 (1) These amounts reflect the number of performance units granted in thousands. The actual payout of shares may range from a minimum of zero shares to a maximum of two shares per unit contingent upon the actual performance against the Performance Measures. The performance units have a three -year vesting term and the actual disbursement of shares, if any, is determined during the first quarter following the end of the three-year vesting period.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Information [Abstract]
Summary Of Financial Information For Company's Reportable Segments	   Exploration and Production Midstream Services Other Total  (in millions)  Three months ended September 30, 2017:  Revenues from external customers $ 475 $ 262 $ – $ 737  Intersegment revenues (5) 472 – 467  Depreciation, depletion and amortization expense 120 15 – 135  Operating income 64 46 – 110  Interest expense (1) 31 – – 31  Gain on derivatives 45 – – 45  Loss on early extinguishment of debt – – (59) (59)  Other income (loss) , net 1 (3) – (2) Benefit for income taxes (1) (14) – – (14)  Assets 4,842 1,240 1,120 (2) 7,202  Capital investments (3) 320 9 2 331   Three months ended September 30, 2016:  Revenues from external customers $ 381 $ 270 $ – $ 651  Intersegment revenues (3) 412 – 409  Depreciation, depletion and amortization expense 83 16 – 99  Impairment of natural gas and oil properties 817 – – 817  Operating income (loss) (777) (4) 52 – (725)  Interest expense (1) 26 – – 26  Gain on derivatives 71 – – 71  Loss on early extinguishment of debt – – (51) (51)  Other income, net 2 1 – 3  Benefit for income taxes (1) (20) – – (20)  Assets 4,015 1,253 1,622 (2) 6,890  Capital investments (3) 179 1 – 180      Exploration and Production Midstream Services Other Total  (in millions)  Nine months ended September 30, 2017:  Revenues from external customers $ 1,572 $ 822 $ – $ 2,394  Intersegment revenues (13) 1,592 – 1,579  Depreciation, depletion and amortization expense 317 47 – 364  Operating income 435 129 – 564  Interest expense (1) 97 – – 97  Gain on derivatives 295 – – 295  Loss on early extinguishment of debt – – (70) (70)  Other income, net 5 1 – 6 Benefit for income taxes (1) (14) – – (14)  Assets 4,842 1,240 1,120 (2) 7,202  Capital investments (3) 921 21 4 946   Nine months ended September 30, 2016:  Revenues from external customers $ 1,015 $ 737 $ – $ 1,752  Intersegment revenues (17) 1,125 – 1,108  Depreciation, depletion and amortization expense 300 49 – 349  Impairment of natural gas and oil properties 2,321 – – 2,321  Operating income (loss) (2,486) (4) 169 (5) – (2,317)  Interest expense (1) 56 1 – 57  Loss on derivatives (27) (1) – (28)  Loss on early extinguishment of debt – – (51) (51)  Other income (loss) , net 3 (2) (1) –  Benefit for income taxes (20) – – (20)  Assets 4,015 1,253 1,622 (2) 6,890  Capital investments (3) 372 3 1 376 (1) Interest expense and the benefit for income taxes by segment are an allocation of corporate amounts as they are incurred at the corporate level. (2) Other assets represent corporate assets not allocated to segments and assets for non-reportable segments. At September 30, 2017 and 2016, other assets includes approximately $989 m illion and $1.5 b illion in cash and cash equivalents, respectively. (3) Capital investments includes a decre ase of $2 million and an increase of $27 million for the three months ended September 30, 2017 and 2016 , respectively, and decreases of $13 million and $24 million for the nine months ended September 30, 2017 and 2016, respectively, relating to the change in capital accruals between periods. (4) Operating income (loss) for the E&P segment includes $2 million and $74 million related to restructuring charges for the three and nine months ended September 30, 2016, respectively. (5) Operating income (loss) for the Midstream services segment includes $3 million related to restructuring charges for the nine months ended September 30, 2016.

Basis Of Presentation (Narrativ

Basis Of Presentation (Narrative) (Details)	9 Months Ended
	Sep. 30, 2017segment
Basis Of Presentation [Abstract]
Number of segments	2

Cash And Cash Equivalents (Summ

Cash And Cash Equivalents (Summary Of Cash And Cash Equivalents) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Cash And Cash Equivalents [Abstract]
Cash	$ 259	$ 254
Marketable securities	680	1,169
Other cash equivalents	50
Total cash and cash equivalents	$ 989	$ 1,423	$ 1,474	$ 15

Reduction In Workforce (Narrati

Reduction In Workforce (Narrative) (Details)	1 Months Ended
	Jan. 31, 2016
Workforce Reduction [Member]
Restructuring Cost and Reserve [Line Items]
Positions eliminated, percent	40.00%

Reduction In Workforce (Summary

Reduction In Workforce (Summary Of Restructuring Charges) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 2	$ 77
Exploration and Production [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	2	74
Midstream Services [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		3
Workforce Reduction [Member]
Restructuring Cost and Reserve [Line Items]
Severance (including payroll taxes)		44
Stock-based compensation		24
Pension and other postretirement benefits	2	5
Other benefits		3
Outplacement services, other		1
Total restructuring charges	2	77
Workforce Reduction [Member] | Executive Management [Member]
Restructuring Cost and Reserve [Line Items]
Severance (including payroll taxes)		1
Stock-based compensation		3
Workforce Reduction [Member] | Exploration and Production [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 2	74
Workforce Reduction [Member] | Midstream Services [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		$ 3

Natural Gas And Oil Properties

Natural Gas And Oil Properties (Narrative) (Details) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016USD ($)$ / bbl$ / MMBTU	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2017$ / bbl$ / MMBTU	Sep. 30, 2016USD ($)
Natural Gas and Oil Properties [Line Items]
Natural gas, oil and NGL reserves discount				10.00%
Period of time needed to calculate ceiling value of reserves	12 months			12 months
Impairment of natural gas and oil properties | $	$ 817	$ 470	$ 1,034		$ 2,321
Natural Gas [Member] | Henry Hub [Member]
Natural Gas and Oil Properties [Line Items]
Full cost ceiling test, price | $ / MMBTU	2.28			3
Oil [Member] | West Texas Intermediate [Member]
Natural Gas and Oil Properties [Line Items]
Full cost ceiling test, price	38.17			46.27
NGL [Member]
Natural Gas and Oil Properties [Line Items]
Full cost ceiling test, price	6.46			12.47

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 16, 2017	Sep. 15, 2017	Sep. 30, 2017	Jul. 31, 2016	Nov. 30, 2015	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Repayments of long-term debt						$ 1,139	$ 1,175
Debt instrument			$ 4,473			$ 4,473		$ 4,684
Common stock, date dividend declared						Sep. 15, 2017
Common stock, date dividend to be paid		Oct. 16, 2017				Oct. 16, 2017
Common Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued				98,900,000
Price per share				$ 13
Proceeds from issuance of shares				$ 1,247
Series B Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Trading day period						20 days
Long-term Debt [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Debt instrument			4,433			$ 4,433		4,643
Long-term Debt [Member] | 2015 Term Loan due December 2020 [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Repayments of long-term debt			$ 327	375		$ 327		423
Debt instrument					$ 750			$ 327
Debt instrument, term					3 years
Senior Notes [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Purchase of note principal				$ 700
Minimum [Member] | Depositary Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued upon conversion			1.85014			1.85014
Minimum [Member] | Series B Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued upon conversion			37.0028			37.0028
Potential number of shares issued upon conversion						63,829,830
Maximum [Member] | Depositary Shares [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued upon conversion			2.17391			2.17391
Maximum [Member] | Series B Preferred Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued upon conversion			43.4782			43.4782
Potential number of shares issued upon conversion						74,999,895
Subsequent Event [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Common stock, shares issued as stock dividend	3,346,703
Common stock dividend, setteled in cash	$ 7.9

Earnings Per Share (Schedule Of

Earnings Per Share (Schedule Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income (loss)	$ 77	$ (708)	$ 712	$ (2,433)
Mandatory convertible preferred stock dividend	27	27	81	81
Participating securities - mandatory convertible preferred stock	7		83
Net Income (Loss) Attributable to Common Stock	$ 43	$ (735)	$ 548	$ (2,514)
Number of common shares: Weighted average outstanding	499,812,926	482,485,150	496,458,435	417,222,661
Number of common shares: Issued upon assumed exercise of outstanding stock options
Number of common shares: Effect of issuance of non-vested restricted common stock	1,202,585		883,512
Number of common shares: Effect of issuance of non-vested performance units	1,275,268		1,185,724
Number of common shares: Effect of issuance of mandatory convertible preferred stock
Number of common shares: Weighted average and potential dilutive outstanding	502,290,779	482,485,150	498,527,671	417,222,661
Earnings (loss) per common share: Basic	$ 0.09	$ (1.52)	$ 1.11	$ (6.02)
Earnings (loss) per common share: Diluted	$ 0.09	$ (1.52)	$ 1.10	$ (6.02)

Earnings Per Share (Schedule 42

Earnings Per Share (Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share) (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	81,920,335	79,944,193	81,453,456	80,469,737
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	180,932	3,409,596	60,973	3,714,095
Unvested Share-Based Payment [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	5,703,086	599,372	5,356,166	993,576
Performance Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	1,036,422	935,330	1,036,422	762,171
Mandatory Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	74,999,895	74,999,895	74,999,895	74,999,895

Derivatives And Risk Manageme43

Derivatives And Risk Management (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Interest Rate Swaps [Member]
Derivative [Line Items]
Derivative liabilities	$ 2	$ 3
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Derivative liabilities	2
Notional amount	$ 170
Derivative, expiration	Jun. 30, 2020
Natural Gas [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative liabilities	$ 23

Derivatives And Risk Manageme44

Derivatives And Risk Management (Schedule Of Derivative Instruments, Notional Amount In BCF, Weighted Average Contract Prices And Fair Value) (Details) $ in Millions, ft³ in Billions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2017USD ($)$ / MMBTU	Sep. 30, 2017USD ($)$ / MMBTUft³	Dec. 31, 2016USD ($)
Fixed Price Swaps - 2017 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		73
Average price per MMBtu	3.06	3.06
Fair Value | $	$ 1	$ 1
Two-way Costless-collars - 2017 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		31
Fair Value | $	$ 1	$ 1
Two-way Costless-collars - 2017 Purchased Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.96	2.96
Two-way Costless-collars - 2017 Sold Calls [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Cap price per MMBtu	3.38	3.38
Three-way Costless-collars - 2017 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		34
Three-way Costless-collars - 2017 Sold Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.29	2.29
Three-way Costless-collars - 2017 Purchased Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.97	2.97
Three-way Costless-collars - 2017 Sold Calls [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Cap price per MMBtu	3.30	3.30
Financial protection on production - 2017 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		138
Fair Value | $	$ 2	$ 2
Fixed Price Swaps - 2018 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		178
Average price per MMBtu	3.02	3.02
Fair Value | $	$ (4)	$ (4)
Two-way Costless-collars - 2018 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		23
Fair Value | $	$ (1)	$ (1)
Two-way Costless-collars - 2018 Purchased Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.97	2.97
Two-way Costless-collars - 2018 Sold Calls [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Cap price per MMBtu	3.56	3.56
Three-way Costless-collars - 2018 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		272
Fair Value | $	$ 7	$ 7
Three-way Costless-collars - 2018 Sold Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.40	2.40
Three-way Costless-collars - 2018 Purchased Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.97	2.97
Three-way Costless-collars - 2018 Sold Calls [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Cap price per MMBtu	3.37	3.37
Financial protection on production - 2018 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		473
Fair Value | $	$ 2	$ 2
Three-way Costless-collars - 2019 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		108
Fair Value | $	$ (1)	$ (1)
Three-way Costless-collars - 2019 Sold Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.50	2.50
Three-way Costless-collars - 2019 Purchased Puts [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Floor price per MMBtu	2.95	2.95
Three-way Costless-collars - 2019 Sold Calls [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Cap price per MMBtu	3.32	3.32
Financial protection on production - 2019 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		108
Fair Value | $	$ (1)	$ (1)
Basis Swaps - 2017 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		32
Basis differential per MMBtu	(0.95)	(0.95)
Fair Value | $	$ 12	$ 12
Basis Swaps - 2018 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		25
Basis differential per MMBtu	(0.63)	(0.63)
Fair Value | $	$ (16)	$ (16)
Basis Swaps [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		57
Fair Value | $	(4)	$ (4)
Call Options - 2017 [Member]
Derivative [Line Items]
Premium paid | $	$ 3	$ 3
Call Options - 2017 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		21
Cap price per MMBtu	3.68	3.68
Premium paid | $		$ 2	$ 2
Call Options - 2018 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		63
Cap price per MMBtu	3.50	3.50
Fair Value | $	$ (9)	$ (9)
Call Options - 2019 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		52
Cap price per MMBtu	3.50	3.50
Fair Value | $	$ (8)	$ (8)
Call Options - 2020 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		32
Cap price per MMBtu	3.75	3.75
Fair Value | $	$ (5)	$ (5)
Call Options [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume (Bcf) | ft³		168
Fair Value | $	$ (22)	$ (22)

Derivatives And Risk Manageme45

Derivatives And Risk Management (Balance Sheet Classification Of Derivative Financial Instruments) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Call Options - 2017 [Member]
Derivatives, Fair Value [Line Items]
Premium paid	$ 3	$ 3
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	146	146	$ 155
Derivative liabilities	171	171	530
Not Designated as Hedging Instrument [Member] | Fixed Price Swaps [Member] | Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	12	12
Not Designated as Hedging Instrument [Member] | Fixed Price Swaps [Member] | Other Long-Term Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1	1	1
Not Designated as Hedging Instrument [Member] | Fixed Price Swaps [Member] | Derivative Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	14	14	175
Not Designated as Hedging Instrument [Member] | Fixed Price Swaps [Member] | Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	2	2	3
Not Designated as Hedging Instrument [Member] | Two-way Costless-collars [Member] | Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	7	7	8
Not Designated as Hedging Instrument [Member] | Two-way Costless-collars [Member] | Other Long-Term Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets			2
Not Designated as Hedging Instrument [Member] | Two-way Costless-collars [Member] | Derivative Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	7	7	49
Not Designated as Hedging Instrument [Member] | Two-way Costless-collars [Member] | Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities			9
Not Designated as Hedging Instrument [Member] | Three-way Costless-collars [Member] | Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	50	50	11
Not Designated as Hedging Instrument [Member] | Three-way Costless-collars [Member] | Other Long-Term Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	56	56	100
Not Designated as Hedging Instrument [Member] | Three-way Costless-collars [Member] | Derivative Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	44	44	70
Not Designated as Hedging Instrument [Member] | Three-way Costless-collars [Member] | Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	56	56	122
Not Designated as Hedging Instrument [Member] | Basis Swaps [Member] | Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	19	19	32
Not Designated as Hedging Instrument [Member] | Basis Swaps [Member] | Other Long-Term Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets			1
Not Designated as Hedging Instrument [Member] | Basis Swaps [Member] | Derivative Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	23	23	13
Not Designated as Hedging Instrument [Member] | Basis Swaps [Member] | Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities			5
Not Designated as Hedging Instrument [Member] | Call Options [Member] | Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1	1
Not Designated as Hedging Instrument [Member] | Call Options [Member] | Derivative Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	8	8	46
Not Designated as Hedging Instrument [Member] | Call Options [Member] | Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	15	15	35
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Derivative Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	1	2
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Other Long-Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 1	1	1
Not Designated as Hedging Instrument [Member] | Call Options - 2017 [Member]
Derivatives, Fair Value [Line Items]
Premium paid		$ 2	$ 2

Derivatives And Risk Manageme46

Derivatives And Risk Management (Summary Of Before Tax Effect Of Fair Value Hedges Not Designated For Hedge Accounting) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Unsettled	$ 31	$ 81	$ 350	$ (48)
Derivative Instrument, Gain (Loss) on Derivatives, Settled	17	(10)	(52)	20
Total gain (loss) on derivatives	48	71	298	(28)
Fixed Price Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Unsettled	(2)	23	174	(17)
Derivative Instrument, Gain (Loss) on Derivatives, Settled	7	(9)	(18)	7
Purchased Put Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Settled				11
Two-way Costless-collars [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Unsettled	3	5	48
Derivative Instrument, Gain (Loss) on Derivatives, Settled			(3)
Three-way Costless-collars [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Unsettled	(1)	1	87	(1)
Derivative Instrument, Gain (Loss) on Derivatives, Settled	1		(4)
Basis Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Unsettled	24	31	(19)	27
Derivative Instrument, Gain (Loss) on Derivatives, Settled	9		(21)	4
Call Options [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Unsettled	6	21	59	(54)
Derivative Instrument, Gain (Loss) on Derivatives, Settled			(6)
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instrument, Gain (Loss) on Derivatives, Unsettled	1		1	(3)
Derivative Instrument, Gain (Loss) on Derivatives, Settled		$ (1)		$ (2)
Call Options - 2017 [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Premium paid	$ 3		$ 3

Reclassifications From Accumu47

Reclassifications From Accumulated Other Comprehensive Income (Loss) (Components Of Accumulated Other Comprehensive Income (Loss)) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, December 31, 2016	$ (39)
Other comprehensive income before reclassifications
Amounts reclassified from other comprehensive income	2
Net current-period other comprehensive income	2
Ending balance, September 30, 2017	(37)
Pension And Other Postretirement [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, December 31, 2016	(19)
Other comprehensive income before reclassifications
Amounts reclassified from other comprehensive income	2
Net current-period other comprehensive income	2
Ending balance, September 30, 2017	(17)
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, December 31, 2016	(20)
Other comprehensive income before reclassifications
Amounts reclassified from other comprehensive income
Net current-period other comprehensive income
Ending balance, September 30, 2017	$ (20)

Reclassifications From Accumu48

Reclassifications From Accumulated Other Comprehensive Income (Loss) (Amounts Reclassified From Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
General and administrative expenses	$ 62	$ 61	$ 170	$ 171
Provision for income taxes	(14)	(20)	(14)	(20)
Net Income (Loss)	$ 77	$ (708)	712	$ (2,433)
Reclassified from Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net Income (Loss)			2
Pension And Other Postretirement [Member] | Reclassified from Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
General and administrative expenses			2
Provision for income taxes
Net Income (Loss)			$ 2

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Amount And Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	1 Months Ended			3 Months Ended	9 Months Ended		12 Months Ended	21 Months Ended
	Sep. 30, 2017	Jul. 31, 2016	Jan. 31, 2015	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Sep. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, net	$ (25)			$ (25)	$ (25)		$ (375)	$ (25)
Repayments of long-term debt					1,139	$ 1,175
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	989			989	989		1,423	989
Senior notes	3,282			3,282	3,282		3,166	3,282
Derivative instruments, net	(25)			(25)	(25)		(375)	(25)
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	989			989	989		1,423	989
Senior notes	3,317			3,317	3,317		3,182	3,317
Derivative instruments, net	(25)			(25)	(25)		$ (375)	(25)
Long-term Debt [Member] | 2015 Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity date, year and month							2020-12
Repayments of long-term debt	327	$ 375			$ 327		$ 423
Long-term Debt [Member] | 2016 Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity date, year and month					2020-12		2020-12
Accelerated maturity date, year and month if not amended, redeemed or refinanced					2019-10
Long-term Debt [Member] | 4.05% Senior Notes due January 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity date, year and month			2020-01		2020-01		2020-01
Repayments of long-term debt	758				$ 758
Long-term Debt [Member] | 2020 Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount to be amended, redeemed or refinanced to avoid acceleration					765			765
Long-term Debt [Member] | Carrying Amount [Member] | 2015 Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans							$ 327
Long-term Debt [Member] | Carrying Amount [Member] | 2016 Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	1,191			1,191	1,191		1,191	1,191
Long-term Debt [Member] | Fair Value [Member] | 2015 Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans							327
Long-term Debt [Member] | Fair Value [Member] | 2016 Term Loan due December 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 1,191			1,191	1,191		1,191	$ 1,191
Call Options - 2017 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premium paid				$ 3	3
Call Options - 2017 [Member] | Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premium paid					$ 2		$ 2

Fair Value Measurements (Summar

Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On Recurring Basis) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ (25)	$ (25)	$ (375)
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	(5)	(5)	(180)
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	(20)	(20)	(195)
Fixed Price Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	13	13	1
Derivative liabilities	(16)	(16)	(178)
Fixed Price Swaps [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	13	13	1
Derivative liabilities	(16)	(16)	(178)
Two-way Costless-collars [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7	7	10
Derivative liabilities	(7)	(7)	(58)
Two-way Costless-collars [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7	7	10
Derivative liabilities	(7)	(7)	(58)
Three-way Costless-collars [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	106	106	111
Derivative liabilities	(100)	(100)	(192)
Three-way Costless-collars [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	106	106	111
Derivative liabilities	(100)	(100)	(192)
Basis Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	19	19	33
Derivative liabilities	(23)	(23)	(18)
Basis Swaps [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	19	19	33
Derivative liabilities	(23)	(23)	(18)
Call Options [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1	1
Derivative liabilities	(23)	(23)	(81)
Call Options [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1	1
Derivative liabilities	(23)	(23)	(81)
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(2)	(2)	(3)
Interest Rate Swaps [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(2)	(2)	(3)
Call Options - 2017 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premium paid	3	3
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	$ (2)	(2)
Not Designated as Hedging Instrument [Member] | Call Options - 2017 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premium paid		$ 2	$ 2

Fair Value Measurements (Reconc

Fair Value Measurements (Reconciliations For Change In Net Fair Value Of Derivative Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Significant Unobservable Inputs (Level 3)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value Measurements [Abstract]
Balance at beginning of period	$ (52)	$ (83)	$ (195)	$ 3
Included in earnings	42	58	141	(13)
Settlements	(10)		34	(15)
Balance at end of period	(20)	(25)	(20)	(25)
Change in gains (losses) included in earnings relating to derivatives still held as of September 30	$ 32	$ 58	$ 175	$ (28)

Debt (Senior Notes - Narrative)

Debt (Senior Notes - Narrative) (Details) - USD ($) $ in Millions	1 Months Ended				3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Jul. 31, 2016	Nov. 30, 2015	Jan. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Net loss on extinguishment of debt	$ 59				$ (59)	$ (51)	$ (11)	$ (70)	$ (51)
Payment of debt extinguishment costs	53
Unamortized debt expense	35				35			35		$ 28
Repayments of long-term debt								1,139	$ 1,175
Long-term Debt [Member]
Debt Instrument [Line Items]
Unamortized debt expense	$ 35				$ 35			$ 35		$ 28
Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt				$ 2,200
Purchase of note principal		$ 700
Senior Notes [Member] | Over LIBOR [Member]
Debt Instrument [Line Items]
Incremental increase in basis points resulting from downgrades								0.25%
Incremental decrease in basis points resulting from upgrades								0.25%
Increase in basis spread		1.75%
3.30% Senior Notes due January 2018 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes				$ 350
Stated interest rate		5.05%		3.30%						3.30%
Maturity date, year and month				2018-01						2018-01
Unamortized debt expense
Repayments of long-term debt							$ 38	$ 38
4.05% Senior Notes due January 2020 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes				$ 850
Stated interest rate	4.05%	5.80%		4.05%	4.05%			4.05%		4.05%
Maturity date, year and month				2020-01				2020-01		2020-01
Unamortized debt expense										$ 5
Repayments of long-term debt	$ 758							$ 758
4.95% Senior Notes due January 2025 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes				$ 1,000
Stated interest rate	4.95%	6.70%		4.95%	4.95%			4.95%		4.95%
Maturity date, year and month				2025-01				2025-01		2025-01
Unamortized debt expense	$ 6				$ 6			$ 6		$ 7
7.50% Senior Notes due February 2018 [Member]
Debt Instrument [Line Items]
Maturity date, year and month								2018-02
7.50% Senior Notes due February 2018 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate							7.50%			7.50%
Maturity date, year and month										2018-02
Unamortized debt expense
Repayments of long-term debt							$ 212	$ 212
7.15% Senior Notes due June 2018 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate							7.15%			7.15%
Maturity date, year and month								2018-06		2018-06
Unamortized debt expense
Repayments of long-term debt							$ 26	$ 26
7.50% Senior Notes due April 2026 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes	$ 650				$ 650			$ 650
Stated interest rate	7.50%				7.50%			7.50%
Maturity date, year and month	2026-04							2026-04
Unamortized debt expense	$ 10				$ 10			$ 10
2015 Term Loan due December 2020 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Maturity date, year and month										2020-12
Debt instrument, term			3 years
Unamortized debt expense										$ 2
Repayments of long-term debt	327	$ 375						327		$ 423
7.75% Senior Notes due October 2027 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes	$ 500				$ 500			$ 500
Stated interest rate	7.75%				7.75%			7.75%
Maturity date, year and month	2027-10							2027-10
Unamortized debt expense	$ 7				$ 7			$ 7
2026 and 2027 Notes [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 1,100
4.10% Senior Notes due March 2022 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	4.10%				4.10%			4.10%		4.10%
Maturity date, year and month								2022-03		2022-03
Unamortized debt expense	$ 4				$ 4			$ 4		$ 4
Maximum [Member] | 3.30% Senior Notes due January 2018 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	5.30%				5.30%			5.30%
Maximum [Member] | 4.05% Senior Notes due January 2020 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	6.05%				6.05%			6.05%
Maximum [Member] | 4.95% Senior Notes due January 2025 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	6.95%				6.95%			6.95%

Debt (2016 Credit Facility - Na

Debt (2016 Credit Facility - Narrative) (Details)	1 Months Ended			3 Months Ended					6 Months Ended	9 Months Ended		12 Months Ended	21 Months Ended
	Sep. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jan. 31, 2015	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2013USD ($)
Debt Instrument [Line Items]
Debt instrument	$ 4,473,000,000							$ 4,473,000,000	$ 4,473,000,000	$ 4,473,000,000		$ 4,684,000,000	$ 4,473,000,000
Repayments of long-term debt										1,139,000,000	$ 1,175,000,000
Long-term Debt [Member]
Debt Instrument [Line Items]
Debt instrument	4,433,000,000							4,433,000,000	4,433,000,000	4,433,000,000		4,643,000,000	4,433,000,000
Long-term Debt [Member] | 2013 Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 66,000,000												$ 2,000,000,000
Repayment of line of credit		285,000,000
Amount outstanding	0							0	0	0			0
Long-term Debt [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		743,000,000
Long-term Debt [Member] | 2013 & 2016 Credit Facilities [Member]
Debt Instrument [Line Items]
Amount outstanding	0							0	0	0			0
Long-term Debt [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Amount outstanding	323,000,000							323,000,000	$ 323,000,000	323,000,000			323,000,000
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 1,934,000,000
Maturity date, year and month		2020-12
Net cash proceeds from asset sales allowed to be retained										$ 500,000,000
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Minimum [Member]
Debt Instrument [Line Items]
Minimum interest coverage ratio									2
Leverage Ratio										4
Liquidity requirement	$ 300,000,000							$ 300,000,000	$ 300,000,000	$ 300,000,000			300,000,000
Collateral coverage ratio	1.50
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage Ratio	4							5.50
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Maximum [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Leverage Ratio				4.50	4.50	5	5
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Eurodollar [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis points										1.75%
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Eurodollar [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis points										2.50%
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis points										0.75%
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis points										1.50%
Revolving Credit Facility And Term Loan Facility [Member] | Long-term Debt [Member] | Over LIBOR [Member]
Debt Instrument [Line Items]
Basis points										2.50%
2016 Term Loan due December 2020 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Debt instrument	$ 1,191,000,000	$ 1,191,000,000						$ 1,191,000,000	1,191,000,000	$ 1,191,000,000		$ 1,191,000,000	1,191,000,000
Maturity date, year and month										2020-12		2020-12
Accelerated maturity date, year and month if not amended, redeemed or refinanced										2019-10
4.05% Senior Notes due January 2020 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Debt instrument	92,000,000							$ 92,000,000	$ 92,000,000	$ 92,000,000		$ 850,000,000	92,000,000
Maturity date, year and month			2020-01							2020-01		2020-01
Repayments of long-term debt	$ 758,000,000									$ 758,000,000
2020 Senior Notes [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Amount to be amended, redeemed or refinanced to avoid acceleration										$ 765,000,000			$ 765,000,000

Debt (2013 Credit Facility - Na

Debt (2013 Credit Facility - Narrative) (Details) - USD ($)	1 Months Ended	9 Months Ended
	Jun. 30, 2016	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2013
Debt Instrument [Line Items]
Debt instrument		$ 4,473,000,000	$ 4,684,000,000
Adjusted debt capital structure, percentage		32.00%
Long-term Debt [Member]
Debt Instrument [Line Items]
Debt instrument		$ 4,433,000,000	4,643,000,000
Long-term Debt [Member] | 2013 Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 66,000,000			$ 2,000,000,000
Repayment of line of credit	285,000,000
Credit facility, maturity date		Dec. 1, 2018
Amount outstanding		$ 0
Debt percentage of adjusted book capital structure covenant		60.00%
Long-term Debt [Member] | 2016 Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	743,000,000
2016 Term Loan due December 2020 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Debt instrument	$ 1,191,000,000	$ 1,191,000,000	$ 1,191,000,000

Debt (2015 Term Loan - Narrativ

Debt (2015 Term Loan - Narrative) (Details) - USD ($) $ in Millions	1 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2017	Jul. 31, 2016	Nov. 30, 2015	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Repayments of long-term debt				$ 1,139	$ 1,175
2015 Term Loan due December 2020 [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
Loans payable			$ 750
Debt instrument, term			3 years
Repayments of long-term debt	$ 327	$ 375		$ 327		$ 423
Maturity date, year and month						2020-12

Debt (Components Of Debt) (Deta

Debt (Components Of Debt) (Details) - USD ($) $ in Millions	Oct. 01, 2017	Sep. 30, 2017	Jul. 31, 2016	Jan. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Sep. 30, 2017	Jun. 30, 2016	Nov. 30, 2015
Debt Instrument [Line Items]
Debt Instrument		$ 4,473			$ 4,473			$ 4,473		$ 4,684	$ 4,473
Unamortized Issuance Expense		(35)			(35)			(35)		(28)	(35)
Unamortized Debt Discount		(2)			(2)			(2)		(3)	(2)
Total		4,436			4,436			4,436		4,653	4,436
Repayment of short-term debt								287	$ 1
Repayments of long-term debt								1,139	1,175
Net loss on extinguishment of debt		59			(59)	$ (51)	$ (11)	$ (70)	$ (51)
7.50% Senior Notes due February 2018 [Member]
Debt Instrument [Line Items]
Maturity date, year and month								2018-02
Short-term Debt [Member]
Debt Instrument [Line Items]
Debt Instrument		40			40			$ 40		41	40
Unamortized Issuance Expense
Unamortized Debt Discount
Total		40			40			40		41	40
Short-term Debt [Member] | 7.35% Senior Notes due October 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument		15			15			15		15	15
Unamortized Issuance Expense
Unamortized Debt Discount
Total		$ 15			$ 15			$ 15		$ 15	$ 15
Stated interest rate		7.35%			7.35%			7.35%		7.35%	7.35%
Maturity date, year and month								2017-10		2017-10
Short-term Debt [Member] | 7.125% Senior Notes due October 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument		$ 25			$ 25			$ 25		$ 25	$ 25
Unamortized Issuance Expense
Unamortized Debt Discount
Total		$ 25			$ 25			$ 25		$ 25	$ 25
Stated interest rate		7.125%			7.125%			7.125%		7.125%	7.125%
Maturity date, year and month								2017-10		2017-10
Short-term Debt [Member] | 7.15% Senior Notes due June 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument										$ 1
Unamortized Issuance Expense
Unamortized Debt Discount
Total										$ 1
Stated interest rate										7.15%
Maturity date, year and month										2018-06
Long-term Debt [Member]
Debt Instrument [Line Items]
Debt Instrument		$ 4,433			$ 4,433			$ 4,433		$ 4,643	$ 4,433
Unamortized Issuance Expense		(35)			(35)			(35)		(28)	(35)
Unamortized Debt Discount		(2)			(2)			(2)		(3)	(2)
Total		4,396			4,396			4,396		4,612	4,396
Long-term Debt [Member] | 2015 Term Loan due December 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument										327			$ 750
Unamortized Issuance Expense										(2)
Unamortized Debt Discount
Total										$ 325
Variable interest rate										3.22%
Maturity date, year and month										2020-12
Repayments of long-term debt		327	$ 375					327		$ 423
Long-term Debt [Member] | 2016 Term Loan due December 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument		1,191			1,191			1,191		1,191	1,191	$ 1,191
Unamortized Issuance Expense		(8)			(8)			(8)		(10)	(8)
Unamortized Debt Discount
Total		1,183			1,183			$ 1,183		$ 1,181	1,183
Variable interest rate								3.70%		3.22%
Maturity date, year and month								2020-12		2020-12
Accelerated maturity date, year and month if not amended, redeemed or refinanced								2019-10
Long-term Debt [Member] | 3.30% Senior Notes due January 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument										$ 38
Unamortized Issuance Expense
Unamortized Debt Discount
Total										$ 38
Stated interest rate			5.05%	3.30%						3.30%
Maturity date, year and month				2018-01						2018-01
Repayments of long-term debt							$ 38	$ 38
Long-term Debt [Member] | 7.50% Senior Notes due February 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument										$ 212
Unamortized Issuance Expense
Unamortized Debt Discount
Total										$ 212
Stated interest rate							7.50%			7.50%
Maturity date, year and month										2018-02
Repayments of long-term debt							$ 212	$ 212
Long-term Debt [Member] | 7.15% Senior Notes due June 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument										$ 25
Unamortized Issuance Expense
Unamortized Debt Discount
Total										$ 25
Stated interest rate							7.15%			7.15%
Maturity date, year and month								2018-06		2018-06
Repayments of long-term debt							$ 26	$ 26
Long-term Debt [Member] | 4.05% Senior Notes due January 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument		92			92			92		$ 850	92
Unamortized Issuance Expense										(5)
Unamortized Debt Discount
Total		$ 92			$ 92			$ 92		$ 845	$ 92
Stated interest rate		4.05%	5.80%	4.05%	4.05%			4.05%		4.05%	4.05%
Maturity date, year and month				2020-01				2020-01		2020-01
Repayments of long-term debt		$ 758						$ 758
Long-term Debt [Member] | 4.10% Senior Notes due March 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument		1,000			$ 1,000			1,000		$ 1,000	$ 1,000
Unamortized Issuance Expense		(4)			(4)			(4)		(4)	(4)
Unamortized Debt Discount										(1)
Total		$ 996			$ 996			$ 996		$ 995	$ 996
Stated interest rate		4.10%			4.10%			4.10%		4.10%	4.10%
Maturity date, year and month								2022-03		2022-03
Long-term Debt [Member] | 4.95% Senior Notes due January 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument		$ 1,000			$ 1,000			$ 1,000		$ 1,000	$ 1,000
Unamortized Issuance Expense		(6)			(6)			(6)		(7)	(6)
Unamortized Debt Discount		(2)			(2)			(2)		(2)	(2)
Total		$ 992			$ 992			$ 992		$ 991	$ 992
Stated interest rate		4.95%	6.70%	4.95%	4.95%			4.95%		4.95%	4.95%
Maturity date, year and month				2025-01				2025-01		2025-01
Long-term Debt [Member] | 2020 Senior Notes [Member]
Debt Instrument [Line Items]
Amount to be amended, redeemed or refinanced to avoid acceleration								$ 765			$ 765
Long-term Debt [Member] | 7.50% Senior Notes due April 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument		$ 650			$ 650			650			650
Unamortized Issuance Expense		(10)			(10)			(10)			(10)
Total		$ 640			$ 640			$ 640			$ 640
Stated interest rate		7.50%			7.50%			7.50%			7.50%
Maturity date, year and month		2026-04						2026-04
Long-term Debt [Member] | 7.75% Senior Notes due October 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument		$ 500			$ 500			$ 500			$ 500
Unamortized Issuance Expense		(7)			(7)			(7)			(7)
Total		$ 493			$ 493			$ 493			$ 493
Stated interest rate		7.75%			7.75%			7.75%			7.75%
Maturity date, year and month		2027-10						2027-10
Senior Notes [Member]
Debt Instrument [Line Items]
Purchase of note principal			$ 700
Subsequent Event [Member] | Short-term Debt [Member] | 7.35% Senior Notes due October 2017 [Member]
Debt Instrument [Line Items]
Repayment of short-term debt	$ 15
Subsequent Event [Member] | Short-term Debt [Member] | 7.125% Senior Notes due October 2017 [Member]
Debt Instrument [Line Items]
Repayment of short-term debt	$ 25
Over LIBOR [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Increase in basis spread			1.75%

Commitments And Contingencies57

Commitments And Contingencies (Narrative) (Details)	9 Months Ended
	Sep. 30, 2017USD ($)plaintiffitem
Commitments And Contingencies [Line Items]
Obligation under transportation agreements	$ 8,858,000,000
Guarantee obligations relative to the firms transportation agreements and gathering project and services	832,000,000
Indemnification liability	$ 0
Arkansas Royalty Litigation [Member] | Arkansas State Court [Member]
Commitments And Contingencies [Line Items]
Number of actions | item	2
Number of cases | item	3
Number of plaintiffs | plaintiff	248
Number of cases removed to federal court | item	2
Pending Regulatory Approval and/or Construction [Member]
Commitments And Contingencies [Line Items]
Obligation under transportation agreements	$ 3,722,000,000

Commitments And Contingencies58

Commitments And Contingencies (Schedule Of Future Obligation Under Transportation Agreements) (Details) $ in Millions	Sep. 30, 2017USD ($)
Other Commitments [Line Items]
Less than 1 year	$ 628
1 to 3 years	1,563
3 to 5 years	1,226
5 to 8 years	1,606
More than 8 years	3,835
Total transportation charges	8,858
Infrastructure Currently in Service [Member]
Other Commitments [Line Items]
Less than 1 year	196
1 to 3 years	1,105
3 to 5 years	524
5 to 8 years	1,492
More than 8 years	1,819
Total transportation charges	5,136
Pending Regulatory Approval and/or Construction [Member]
Other Commitments [Line Items]
Less than 1 year	432
1 to 3 years	458
3 to 5 years	702
5 to 8 years	114
More than 8 years	2,016
Total transportation charges	$ 3,722

Pension Plan And Other Postre59

Pension Plan And Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer contributions			$ 11
Company's expected additional annual contribution	$ 3		$ 3
Common Stock in Treasury, Shares	31,269		31,269		31,269
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cash curtailment gain (loss)				$ (1)
Settlement loss		$ (2)		(10)
Net periodic benefit cost (gain)	$ 3	4	$ 8	20
Curtailment gain (loss)				(1)
Benefit obligation	32		32		$ 36
Discount rate						4.20%	4.60%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cash curtailment gain (loss)				6
Net periodic benefit cost (gain)	1	$ 1	2	(4)
Curtailment gain (loss)				$ 6
Benefit obligation	$ 14		$ 14		$ 13
Discount rate						4.20%	4.60%
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Common stock purchased under the terms of the Non-Qualified Plan presented as treasury stock			10,652		31,269

Pension Plan And Other Postre60

Pension Plan And Other Postretirement Benefits (Pension And Other Postretirement Benefit Costs) (Details) - Pension Benefits [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 3	$ 7	$ 9
Interest cost	2	1	4	4
Expected return on plan assets	(1)	(2)	(4)	(5)
Amortization of prior service cost
Amortization of net loss			1	1
Curtailment loss				1
Settlement loss		2		10
Net periodic benefit cost	$ 3	$ 4	$ 8	$ 20

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Jan. 31, 2016	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to the Company's unvested stock option grants, restricted stock grants, and performance units		$ 67
Weighted average period over which cost is recognized, years		3 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, exercised, number of options
Liability-Classified Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for stock awards from grant date		3 years
Workforce Reduction [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Positions eliminated, percent	40.00%

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule Of Stock-Based Compensation Costs) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation cost - expensed	$ 7	$ 6	$ 19	$ 43
Stock-based compensation cost - capitalized	$ 2	$ 2	$ 10	7
Workforce Reduction [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation cost - expensed				16
Executive Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation cost - expensed				$ 3

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary Of Stock Option Activity) (Details) - Stock Options [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, Outstanding at December 31, 2016, Number of Options | shares	5,416
Stock options, Granted, Number of Options | shares	1,604
Stock options, Exercised, Number of Options | shares
Stock options, Forfeited or expired, Number of Options | shares	(725)
Stock options, Outstanding at September 30, 2017, Number of Options | shares	6,295
Stock options, Exercisable at September 30, 2017, Number of Options | shares	3,336
Stock options, Outstanding at December 31, 2016, Weighted Average Exercise Price | $ / shares	$ 23.46
Stock options, Granted, Weighted Average Exercise Price | $ / shares	8
Stock options, Exercised, Weighted Average Exercise Price | $ / shares
Stock options, Forfeited or expired, Weighted Average Exercise Price | $ / shares	17.92
Stock options, Outstanding at September 30, 2017, Weighted Average Exercise Price | $ / shares	20.16
Stock options, Exercisable at September 30, 2017, Weighted Average Exercise Price | $ / shares	$ 29.37

Stock-Based Compensation (Sum64

Stock-Based Compensation (Summary Of Restricted Stock Activity) (Details) - Restricted Stock [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested shares/units at December 31, 2016, Number of Shares | shares	3,321
Granted, Number of Shares/Units | shares	5,036
Vested, Number of Shares/Units | shares	(247)
Forfeited, Number of Shares/Units | shares	(609)
Unvested shares/units at September 30, 2017, Number of Shares | shares	7,501
Unvested shares/units at December 31, 2016, Weighted Average Fair Value | $ / shares	$ 11.85
Granted, Weighted Average Fair Value | $ / shares	8.39
Vested, Weighted Average Fair Value | $ / shares	9.40
Forfeited, Weighted Average Fair Value | $ / shares	10.16
Unvested shares at September 30, 2017, Weighted Average Fair Value | $ / shares	$ 9.68

Stock-Based Compensation (Sum65

Stock-Based Compensation (Summary Of Performance Unit Activity) (Details) - Performance Units [Member]	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested shares/units at December 31, 2016, Number of Shares	719,000
Granted, Number of Shares/Units	1,197,000
Vested, Number of Shares/Units	(42,000)
Forfeited, Number of Shares/Units	(472,000)
Unvested shares/units at September 30, 2017, Number of Shares	1,402,000
Unvested shares/units at December 31, 2016, Weighted Average Fair Value | $ / shares	$ 11.46
Granted, Weighted Average Fair Value | $ / shares	10.47
Vested, Weighted Average Fair Value | $ / shares	5.94
Forfeited, Weighted Average Fair Value | $ / shares	9.74
Unvested shares at September 30, 2017, Weighted Average Fair Value | $ / shares	$ 10.78
Vesting period for stock awards from grant date	3 years
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of Shares/Units	0
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of Shares/Units	2

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended				6 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Revenues		$ 737	$ 651				$ 2,394	$ 1,752
Depreciation, depletion and amortization expense		135	99				364	349
Impairment of natural gas and oil properties			817	$ 470	$ 1,034			2,321
Operating income (loss)		110	(725)				564	(2,317)
Interest expense		31	26				97	57
Gain (loss) on derivatives		45	71				295	(28)
Loss on Early Extinguishment of Debt	$ 59	(59)	(51)			$ (11)	(70)	(51)
Other income (loss), net		(2)	3				6
Benefit for income taxes		(14)	(20)				(14)	(20)
Assets	7,202	7,202	6,890				7,202	6,890	$ 7,076
Capital investments		331	180				946	376
Restructuring charges			2					77
Cash and cash equivalents	989	989	1,474				989	1,474	$ 1,423	$ 15
Change in accrued expenditures		(2)	27				(13)	(24)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues		(467)	(409)				(1,579)	(1,108)
Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues		475	381				1,572	1,015
Depreciation, depletion and amortization expense		120	83				317	300
Impairment of natural gas and oil properties			817					2,321
Operating income (loss)		64	(777)				435	(2,486)
Interest expense		31	26				97	56
Gain (loss) on derivatives		45	71				295	(27)
Other income (loss), net		1	2				5	3
Benefit for income taxes		(14)	(20)				(14)	(20)
Assets	4,842	4,842	4,015				4,842	4,015
Capital investments		320	179				921	372
Restructuring charges			2					74
Exploration and Production [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues		5	3				13	17
Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues		262	270				822	737
Depreciation, depletion and amortization expense		15	16				47	49
Operating income (loss)		46	52				129	169
Interest expense								1
Gain (loss) on derivatives								(1)
Other income (loss), net		(3)	1				1	(2)
Assets	1,240	1,240	1,253				1,240	1,253
Capital investments		9	1				21	3
Restructuring charges								3
Midstream Services [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues		(472)	(412)				(1,592)	(1,125)
Other [Member]
Segment Reporting Information [Line Items]
Loss on Early Extinguishment of Debt		(59)	(51)				(70)	(51)
Other income (loss), net								(1)
Assets	1,120	1,120	1,622				1,120	1,622
Capital investments		2					4	1
Cash and cash equivalents	$ 989	989	1,500				989	1,500
Marketing [Member] | Midstream Services [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues		$ (422)	$ (355)				$ (1,436)	$ (941)

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Taxes [Abstract]
Effective tax rate	(21.00%)	3.00%	(2.00%)	1.00%
Increase (decrease) in valuation allowance	$ (38)	$ 256	$ (220)	$ 903

New Accounting Pronouncements (

New Accounting Pronouncements (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
New Accounting Pronouncements [Abstract]
Net cumulative-effect adjustment	$ 59