Southwestern Energy (SWN) 10-Q 6 Aug 19 2019 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2019	Aug. 02, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-08246
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Registrant Name	SOUTHWESTERN ENERGY CO
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	71-0205415
Entity Address, Address Line One	10000 Energy Drive
Entity Address, City or Town	Spring,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77389
City Area Code	832
Local Phone Number	796-1000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Central Index Key	0000007332
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, Par Value $0.01
Trading Symbol	SWN
Entity Common Stock, Shares Outstanding		541,316,769
Amendment Flag	false
Security Exchange Name	NYSE

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018
Operating Revenues:
Total operating revenues	$ 667	$ 816		$ 1,657	$ 1,736
Operating Costs and Expenses:
Operating expenses	169	193		334	382
General and administrative expenses	40	59		77	114
Loss on sale of operating assets	3	0		3	0
Restructuring charges	2	18		5	18
Depreciation, depletion and amortization	121	142		233	285
Taxes, other than income taxes	17	15		36	38
Total operating costs and expense	645	692		1,422	1,357
Operating Income	22	124		235	379
Interest Expense:
Interest on debt	41	59		83	124
Other interest charges	2	2		3	4
Interest capitalized	(28)	(29)		(57)	(57)
Total Interest Expense	15	32		29	71
Gain (Loss) on Derivatives	152	(36)		120	(43)
Loss on Early Extinguishment of Debt	0	(8)		0	(8)
Other Income (Loss), Net	(6)	3		(5)	2
Income Before Income Taxes	153	51		321	259
Provision (Benefit) for Income Taxes
Current	0	0		0	0
Deferred	15	0		(411)	0
Total Provision (Benefit) from Income Taxes	15	0		(411)	0
Net Income	138	51	[1]	732	259	[1]
Participating securities - mandatory convertible preferred stock	0	0		0	2
Net Income Attributable to Common Stock	$ 138	$ 51		$ 732	$ 257
Earnings Per Common Share
Basic (in dollars per share)	$ 0.26	$ 0.09		$ 1.36	$ 0.45
Diluted (in dollars per share)	$ 0.26	$ 0.09		$ 1.35	$ 0.44
Weighted Average Common Shares Outstanding:
Basic (in shares)	539,005,941	581,159,200		539,362,984	576,255,744
Diluted (in shares)	539,947,053	582,878,106		540,624,742	578,222,740
Gas sales
Operating Revenues:
Total operating revenues	$ 275	$ 407		$ 705	$ 947
Oil sales
Operating Revenues:
Total operating revenues	47	44		86	79
NGL sales
Operating Revenues:
Total operating revenues	58	75		139	140
Marketing
Operating Revenues:
Total operating revenues	287	265		725	518
Gas gathering
Operating Revenues:
Total operating revenues	0	24		0	48
Other
Operating Revenues:
Total operating revenues	0	1		2	4
Marketing purchases
Operating Costs and Expenses:
Marketing purchases	$ 293	$ 265		$ 734	$ 520
[1]	In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	[1]	Jun. 30, 2019	Jun. 30, 2018	[1]
Statement of Comprehensive Income [Abstract]
Net income		$ 138	$ 51		$ 732	$ 259
Change in value of pension and other postretirement liabilities:
Amortization of prior service cost and net loss included in net periodic pension cost	[2]	4	0		4	0
Comprehensive income		$ 142	$ 51		$ 736	$ 259
[1]	In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.
[2]	Primarily related to settlement of pension assets in the second quarter of 2019. Net of $1 million in taxes for the three and six months ended June 30, 2019.

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Defined benefit plan, tax	$ 1	$ 1

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 155	$ 201
Accounts receivable, net	358	581
Derivative assets	209	130
Other current assets	42	44
Total current assets	764	956
Natural gas and oil properties, using the full cost method, including $1,678 million as of June 30, 2019 and $1,755 million as of December 31, 2018 excluded from amortization	24,823	24,180
Other	555	525
Less: Accumulated depreciation, depletion and amortization	(20,279)	(20,049)
Total property and equipment, net	5,099	4,656
Deferred tax assets	410	0
Other long-term assets	272	185
TOTAL ASSETS	6,545	5,797
Current liabilities:
Current portion of long-term debt	52	0
Accounts payable	585	609
Taxes payable	52	58
Interest payable	53	52
Derivative liabilities	67	79
Other current liabilities	103	48
Total current liabilities	912	846
Long-term debt	2,267	2,318
Pension and other postretirement liabilities	39	46
Other long-term liabilities	245	225
Total long-term liabilities	2,551	2,589
Commitments and contingencies (Note 13)
Equity:
Common stock, $0.01 par value; 1,250,000,000 shares authorized; issued 585,478,345 shares as of June 30, 2019 and 585,407,107 shares as of December 31, 2018	6	6
Additional paid-in capital	4,720	4,715
Accumulated deficit	(1,410)	(2,142)
Accumulated other comprehensive loss	(32)	(36)
Common stock in treasury, 44,353,224 shares as of June 30, 2019 and 39,092,537 shares as of December 31, 2018	(202)	(181)
Total equity	3,082	2,362
TOTAL LIABILITIES AND EQUITY	$ 6,545	$ 5,797

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Natural gas and oil properties, using the full cost method, costs excluded from amortization	$ 1,678	$ 1,755
Common stock, par value (in dollars per shares)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,250,000,000	1,250,000,000
Common stock, shares issued (in shares)	585,478,345	585,407,107
Treasury stock, shares (in shares)	44,353,224	39,092,537

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows From Operating Activities:
Net income	$ 732	$ 259	[1]
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	233	285
Amortization of debt issuance costs	2	4
Deferred income taxes	(411)	0
(Gain) loss on derivatives, unsettled	(96)	54
Stock-based compensation	4	9
Loss on early extinguishment of debt	0	8
Loss on sale of assets, net	3	0
Other	10	1
Change in assets and liabilities:
Accounts receivable	221	12
Accounts payable	(129)	53
Taxes payable	(6)	(4)
Interest payable	1	(1)
Inventories	4	(7)
Other assets and liabilities	(25)	(9)
Net cash provided by operating activities	543	664
Cash Flows From Investing Activities:
Capital investments	(586)	(684)
Proceeds from sale of property and equipment	26	6
Other	0	3
Net cash used in investing activities	(560)	(675)
Cash Flows From Financing Activities:
Payments on long-term debt	0	(1,191)
Payments on revolving credit facility	0	(645)
Borrowings under revolving credit facility	0	1,005
Change in bank drafts outstanding	(7)	0
Debt issuance costs	0	(9)
Purchase of treasury stock	(21)	0
Preferred stock dividend	0	(27)
Cash paid for tax withholding	(1)	(1)
Net cash used in financing activities	(29)	(868)
Decrease in cash and cash equivalents	(46)	(879)
Cash and cash equivalents at beginning of year	201	916
Cash and cash equivalents at end of period	$ 155	$ 37
[1]	In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions		Total		Common Stock	Preferred Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Common Stock in Treasury
Balance beginning at Dec. 31, 2017		$ 1,979		$ 5		$ 4,698	$ (2,679)	$ (44)	$ (1)
Balance (in shares) at Dec. 31, 2017				512,134,311	1,725,000				31,269,000,000
Comprehensive income:
Net income		208					208
Comprehensive income		208
Stock-based compensation		7				7
Conversion of preferred stock (in shares)				74,998,614	(1,725,000)
Conversion of preferred stock				$ 1		(1)
Issuance of restricted stock (in shares)				5,076
Cancellation of restricted stock (in shares)				(160,168)
Performance units vested (in shares)				214,866
Tax withholding - stock compensation (in shares)				(338,808)
Tax withholding - stock compensation		(1)				(1)
Balance (in shares) at Mar. 31, 2018				586,853,891	0				31,269,000,000
Balance ending at Mar. 31, 2018		2,193		$ 6		4,703	(2,471)	(44)	$ (1)
Balance beginning at Dec. 31, 2017		1,979		$ 5		4,698	(2,679)	(44)	$ (1)
Balance (in shares) at Dec. 31, 2017				512,134,311	1,725,000				31,269,000,000
Comprehensive income:
Net income	[1]	259
Other comprehensive income		0
Comprehensive income	[1]	259
Balance (in shares) at Jun. 30, 2018				586,430,101	0				31,269,000,000
Balance ending at Jun. 30, 2018		2,250		$ 6		4,709	(2,420)	(44)	$ (1)
Balance beginning at Dec. 31, 2017		1,979		$ 5		4,698	(2,679)	(44)	$ (1)
Balance (in shares) at Dec. 31, 2017				512,134,311	1,725,000				31,269,000,000
Balance (in shares) at Dec. 31, 2018				585,407,107					39,092,537
Balance ending at Dec. 31, 2018		2,362		$ 6		4,715	(2,142)	(36)	$ (181)
Balance beginning at Mar. 31, 2018		2,193		$ 6		4,703	(2,471)	(44)	$ (1)
Balance (in shares) at Mar. 31, 2018				586,853,891	0				31,269,000,000
Comprehensive income:
Net income		51	[1]				51
Other comprehensive income		0
Comprehensive income	[1]	51
Stock-based compensation		6				6
Issuance of restricted stock (in shares)				307,743
Cancellation of restricted stock (in shares)				(722,465)
Tax withholding - stock compensation (in shares)				(9,068)
Balance (in shares) at Jun. 30, 2018				586,430,101	0				31,269,000,000
Balance ending at Jun. 30, 2018		$ 2,250		$ 6		4,709	(2,420)	(44)	$ (1)
Comprehensive income:
Treasury stock (in shares)		39,061,269
Treasury stock		$ (180)
Balance (in shares) at Dec. 31, 2018				585,407,107					39,092,537
Balance ending at Dec. 31, 2018		2,362		$ 6		4,715	(2,142)	(36)	$ (181)
Comprehensive income:
Net income		594					594
Comprehensive income		594
Stock-based compensation		$ 3				3
Issuance of restricted stock (in shares)				8,798
Cancellation of restricted stock (in shares)				(128,324)
Treasury stock (in shares)		5,260,687							5,260,687
Treasury stock		$ (21)							$ (21)
Performance units vested (in shares)				535,802
Tax withholding - stock compensation (in shares)				(274,657)
Tax withholding - stock compensation		(1)				(1)
Balance (in shares) at Mar. 31, 2019				585,548,726					44,353,224
Balance ending at Mar. 31, 2019		2,937		$ 6		4,717	(1,548)	(36)	$ (202)
Balance beginning at Dec. 31, 2018		2,362		$ 6		4,715	(2,142)	(36)	$ (181)
Balance (in shares) at Dec. 31, 2018				585,407,107					39,092,537
Comprehensive income:
Net income		732
Other comprehensive income		4						4
Comprehensive income		736
Balance (in shares) at Jun. 30, 2019				585,478,345					44,353,224
Balance ending at Jun. 30, 2019		3,082		$ 6		4,720	(1,410)	(32)	$ (202)
Balance beginning at Mar. 31, 2019		2,937		$ 6		4,717	(1,548)	(36)	$ (202)
Balance (in shares) at Mar. 31, 2019				585,548,726					44,353,224
Comprehensive income:
Net income		138					138
Other comprehensive income		4						4
Comprehensive income		142
Stock-based compensation		3				3
Issuance of restricted stock (in shares)				6,424
Cancellation of restricted stock (in shares)				(72,555)
Tax withholding - stock compensation (in shares)				(4,250)
Balance (in shares) at Jun. 30, 2019				585,478,345					44,353,224
Balance ending at Jun. 30, 2019		$ 3,082		$ 6		$ 4,720	$ (1,410)	$ (32)	$ (202)
[1]	In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	BASIS OF PRESENTATION 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 marketing business (“Midstream”). Southwestern conducts most of its business through subsidiaries and operates principally in two segments: E&P and Midstream. The Company also operates drilling rigs located in Pennsylvania and West Virginia and provides oilfield products and services, principally serving its E&P operations. The Company’s historical financial and operating results include its Fayetteville Shale E&P and related midstream gathering businesses, which were sold in early December 2018 (the “Fayetteville Shale sale”). The sale is discussed in further detail in Note 2 . E&P. Southwestern’s primary business is the exploration for and production of natural gas, oil and NGLs, with ongoing operations focused on the development of unconventional natural gas and oil reservoirs located in Pennsylvania and West Virginia. The Company’s operations in northeast Pennsylvania, herein referred to as “Northeast Appalachia,” are primarily focused on the unconventional natural gas reservoir known as the Marcellus Shale. Operations in West Virginia and southwest Pennsylvania, herein referred to as “Southwest Appalachia,” are focused on the Marcellus Shale, the Utica and the Upper Devonian unconventional natural gas and oil reservoirs. Collectively, Southwestern refers to its properties located in Pennsylvania and West Virginia as the “Appalachian Basin.” Midstream. Southwestern’s marketing activities capture opportunities that arise through the marketing and transportation of natural gas, oil and NGLs primarily produced in its E&P operations. The accompanying 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 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 consolidated financial statements be read in conjunction with the consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 (“2018 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 Statements included in the Company’s 2018 Annual Report.

Divestitures

Divestitures	6 Months Ended
	Jun. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Divestitures	DIVESTITURES On August 30, 2018 , the Company entered into an agreement with Flywheel Energy Operating, LLC to sell 100% of the equity in the Company’s subsidiaries that owned and operated its Fayetteville Shale E&P and related midstream gathering assets for $1,865 million in cash, subject to customary closing adjustments, with an economic effective date of July 1, 2018 . On December 3, 2018 , the Company closed on the Fayetteville Shale sale and received approximately $1,650 million, which included preliminary purchase price adjustments of approximately $215 million primarily related to the net cash flows from the economic effective date to the closing date. The Company retained certain contractual commitments related to firm transportation, with the buyer obligated to pay the transportation provider directly for these charges. As of June 30, 2019 , approximately $162 million of these contractual commitments remain of which the Company will reimburse the buyer for certain of these potential obligations up to approximately $82 million through 2020 depending on the buyer’s actual use. At June 30, 2019 , the Company has recorded a $68 million liability for the estimated future payments. From the proceeds received, $914 million was used to repurchase $900 million of the Company’s outstanding senior notes, including premiums and $9 million in accrued interest paid in December 2018 . In addition, $201 million, including approximately $1 million in commissions, was used to repurchase approximately 44 million shares of the Company’s outstanding common stock, including $21 million during the first quarter of 2019 . The Company is using the remaining net proceeds from the sale to supplement Appalachian Basin development and for general corporate purposes. In June 2019, the Company sold non-core acreage for $25 million . There was no production or proved reserves associated with this acreage.

Restructuring Charges

Restructuring Charges	6 Months Ended
	Jun. 30, 2019
Restructuring and Related Activities [Abstract]
Restructuring Charges	RESTRUCTURING CHARGES In December 2018 , the Company closed on the sale of the equity in certain of its subsidiaries that owned and operated its Fayetteville Shale E&P and related midstream gathering assets in Arkansas. As part of the transaction, most employees associated with those assets became employees of the buyer although the employment of some was, or will be, terminated. All affected employees were offered a severance package, which included a one-time cash payment depending on length of service and, if applicable, the current value of a portion of equity awards that were forfeited. As of June 30, 2019 , a liability of approximately $0.4 million for severance payments has been accrued for the remaining Fayetteville Shale sale-related employment terminations in 2019 . On June 27, 2018, the Company notified affected employees of a workforce reduction plan, which resulted primarily from a previously announced study of structural, process and organizational changes to enhance shareholder value and continues with respect to other aspects of the Company’s business activities. Affected employees were offered a severance package, which included a one-time cash payment depending on length of service and, if applicable, current value of a portion of equity awards that were forfeited. The following table presents a summary of the restructuring charges included in Operating Income for the three and six months ended June 30, 2019 and 2018: For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Severance (including payroll taxes) $ 1 $ 17 $ 3 $ 17 Office consolidation 1 — 2 — Professional fees — 1 — 1 Total restructuring charges (1) $ 2 $ 18 $ 5 $ 18 (1) Total restructuring charges were $2 million and $ 5 million for the Company’s E&P segment for the three and six months ended June 30, 2019 , respectively, and $16 million and $2 million for the Company’s E&P and Midstream segments, respectively, for the three and six months ended June 30, 2018. The following table presents a reconciliation of the liability associated with the Company’s restructuring activities at June 30, 2019 , which is reflected in accounts payable on the consolidated balance sheet: (in millions) June 30, 2019 Liability at December 31, 2018 $ 5 Additions 5 Distributions (10 ) Liability at June 30, 2019 $ —

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	LEASES 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. The codification was amended through additional ASUs. For public entities, Update 2016-02 became effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company adopted ASC 842 with an effective date of January 1, 2019 using the modified retrospective approach for all leases that existed at the date of initial application. The Company elected to apply the transition as of the beginning of the period of adoption. For leases that existed at the period of adoption on January 1, 2019, the incremental borrowing rate as of the application date was used to calculate the present value of remaining lease payments. The standard provides optional practical expedients to ease the burden of transition. The Company has adopted the following practical expedients through implementation: • an election not to apply the recognition requirements in the leases standard to short-term leases and recognize lease payments in the consolidated statement of operations (a lease that at commencement date has an initial term of 12 months or less and does not contain a purchase option that the Company is reasonably certain to exercise); • a package of practical expedients to not reassess: whether a contract is or contains a lease, lease classification and initial direct costs; • a practical expedient that permits combining lease and non-lease components in a contract and accounting for the combination as a lease (elected by asset class); • a practical expedient to not reassess certain land easements in existence prior to January 1, 2019; and • an election to adopt the modified retrospective approach for all leases existing at or entered into after the initial date of adoption which does not require a restatement of prior period. No cumulative-effect adjustment to retained earnings was required as a result of the modified retrospective approach. Upon adoption of ASC 842, the Company recognized a discounted right-of-use asset and corresponding lease liability with opening balances of approximately $105 million as of January 1, 2019 . The adoption of the standard did not materially change the Company’s consolidated statement of operations or its consolidated statement of cash flows. The Company determines if a contract contains a lease at inception. A lease is defined as a contract, or part of a contract, that conveys the right to control the use of identified property, plant or equipment (an identified asset) for a period of time in exchange for consideration. A right-of-use asset and corresponding lease liability are recognized on the balance sheet at commencement at an amount based on the present value of the remaining lease payments over the lease term. As the implicit rate of the lease is not always readily determinable, the Company uses the incremental borrowing rate to calculate the present value of the lease payments based on information available at commencement date. Operating right-of-use assets are included in other long-term assets while operating lease liabilities are included in other current and other long-term liabilities on the consolidated balance sheet. The Company does not have any financing lease type of arrangements as of June 30, 2019 . By policy election, leases with an initial term of twelve months or less are not recorded on the balance sheet. The Company recognizes lease expense for these leases on a straight-line basis, and variable lease payments are recognized in the period as incurred. Variable lease costs were immaterial through the second quarter ended June 30, 2019 . Certain leases contain both lease and non-lease components. The Company has chosen to account for most of these leases as a single lease component instead of bifurcating lease and non-lease components. However, for compression service leases and fleet vehicle leases, the lease and non-lease components are accounted for separately. The Company leases drilling rigs, pressure pumping equipment, vehicles, office space, certain water transportation lines, an aircraft and other equipment under non-cancelable operating leases expiring through 2032. Certain lease agreements include options to renew the lease, early terminate the lease or purchase the underlying asset(s). The Company determines the lease term at the lease commencement date as the non-cancelable period of the lease, including options to extend or terminate the lease when such an option is reasonably certain to be exercised. The Company’s water transportation lines are the only leases with renewal options that are reasonably certain to be exercised. These renewal options are reflected in the right-of-use asset and lease liability balances. The Company has a residual value guarantee related to its headquarters office building, which would be due only if, at the end of the lease term, the building is either purchased by the Company or marketed to a third party where the purchase price is less than the residual value guarantee. In July 2019, the headquarters office building was sold to a third party, which resulted in the Company making an immaterial short-fall payment to the building’s current lessor. During July 2019, the Company terminated its existing lease agreement and entered into a new lease agreement for a smaller portion of the headquarters office building. The components of lease costs are shown below: For the six months ended (in millions) Operating lease cost $ 22 Short-term lease cost 31 Variable lease cost — Total lease cost $ 53 As of June 30, 2019 , the Company has operating leases of $4 million , related primarily to compressor leases, that have been executed but not yet commenced. These operating leases are planned to commence during 2019 with lease terms expiring through 2022. The Company’s existing operating leases do not contain any material restrictive covenants. Supplemental cash flow information related to leases is set forth below: For the six months ended (in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 22 Right-of use assets obtained in exchange for new operating liabilities: Operating leases $ 6 Supplemental balance sheet information related to leases is as follows: Right-of-use asset balance: (in millions) June 30, 2019 Operating leases $ 103 Lease liability balance: (in millions) Short-term operating leases $ 47 Long-term operating leases 56 Total operating leases $ 103 Weighted average remaining lease term: (years) Operating leases 3.8 Weighted average discount rate: Operating leases 6.28 % Maturity analysis of operating lease liabilities: (in millions) June 30, 2019 2019 $ 22 2020 42 2021 19 2022 10 2023 8 2024 5 Thereafter 9 Total undiscounted lease liability 115 Imputed interest (12 ) Total discounted lease liability $ 103 (in millions) December 31, 2018 2019 $ 38 2020 28 2021 14 2022 6 2023 5 Thereafter 4 Total minimum payments required $ 95

Revenue Recognition

Revenue Recognition	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	REVENUE RECOGNITION Revenues from Contracts with Customers Natural gas and liquids. Natural gas, oil and natural gas liquid (“NGL”) sales are recognized when control of the product is transferred to the customer at a designated delivery point. The pricing provisions of the Company’s contracts are primarily tied to a market index with certain adjustments based on factors such as delivery, quality of the product and prevailing supply and demand conditions in the geographic areas in which the Company operates. Under the Company’s sales contracts, the delivery of each unit of natural gas, oil and NGLs represents a separate performance obligation, and revenue is recognized at the point in time when the performance obligations are fulfilled. There is no significant financing component to the Company’s revenues as payment terms are typically within 30 to 60 days of control transfer. Furthermore, consideration from a customer corresponds directly with the value to the customer of the Company’s performance completed to date. As a result, the Company recognizes revenue in the amount to which the Company has a right to invoice and has not disclosed information regarding its remaining performance obligations. The Company records revenue from its natural gas and liquids production in the amount of its net revenue interest in sales from its properties. Accordingly, natural gas and liquid sales are not recognized for deliveries in excess of the Company’s net revenue interest, while natural gas and liquid sales are recognized for any under-delivered volumes. Production imbalances are recorded as receivables and payables and not contract assets or contract liabilities as the imbalances are between the Company and other working interest owners, not the end customer. Marketing. The Company, through its marketing affiliate, generally markets natural gas, oil and NGLs for its affiliated E&P companies as well as other joint interest owners who choose to market with Southwestern. In addition, the Company markets some products purchased from third parties. Marketing revenues for natural gas, oil and NGL sales are recognized when control of the product is transferred to the customer at a designated delivery point. The pricing provisions of the Company’s contracts are primarily tied to a market index with certain adjustments based on factors such as delivery, quality of the product and prevailing supply and demand conditions. Under the Company’s marketing contracts, the delivery of each unit of natural gas, oil and NGLs represents a separate performance obligation, and revenue is recognized at the point in time when the performance obligations are fulfilled. Customers are invoiced and revenues are recorded each month as natural gas, oil and NGLs are delivered, and payment terms are typically within 30 to 60 days of control transfer. Furthermore, consideration from a customer corresponds directly with the value to the customer of the Company’s performance completed to date. As a result, the Company recognizes revenue in the amount to which the Company has a right to invoice and has not disclosed information regarding its remaining performance obligations. Gas gathering. Prior to its sale in December 2018 as part of the Fayetteville Shale sale, the Company, through its gathering affiliate, gathered natural gas pursuant to a variety of contracts with customers, including an affiliated E&P company. The performance obligations for gas gathering services included delivery of each unit of natural gas to the designated delivery point, which may include treating of certain natural gas units to meet interstate pipeline specifications. Revenue was recognized at the point in time when performance obligations were fulfilled. Under the Company’s gathering contracts, customers were invoiced and revenue was recognized each month based on the volume of natural gas transported and treated at a contractually agreed upon price per unit. Payment terms were typically within 30 to 60 days of completion of the performance obligations. Furthermore, consideration from a customer corresponded directly with the value to the customer of the Company’s performance completed to date. As a result, the Company recognized revenue in the amount to which the Company had a right to invoice and had not disclosed information regarding its remaining performance obligations. Any imbalances were settled on a monthly basis by cashing-out with the respective shipper. Accordingly, there were no contract assets or contract liabilities related to the Company’s gas gathering revenues. Disaggregation of Revenues The Company presents a disaggregation of E&P revenues by product on the consolidated statements of operations net of intersegment revenues. The following table reconciles operating revenues as presented on the consolidated statements of operations to the operating revenues by segment: (in millions) E&P Midstream Intersegment Revenues Total Three months ended June 30, 2019 Gas sales $ 267 $ — $ 8 $ 275 Oil sales 46 — 1 47 NGL sales 58 — — 58 Marketing — 626 (339 ) 287 Total $ 371 $ 626 $ (330 ) $ 667 Three months ended June 30, 2018 Gas sales $ 400 $ — $ 7 $ 407 Oil sales 44 — — 44 NGL sales 75 — — 75 Marketing — 728 (463 ) 265 Gas gathering (1) — 69 (45 ) 24 Other (2) 1 — — 1 Total $ 520 $ 797 $ (501 ) $ 816 (in millions) E&P Midstream Intersegment Total Six months ended June 30, 2019 Gas sales $ 688 $ — $ 17 $ 705 Oil sales 85 — 1 86 NGL sales 139 — — 139 Marketing — 1,566 (841 ) 725 Other (2) 1 1 — 2 Total $ 913 $ 1,567 $ (823 ) $ 1,657 Six months ended June 30, 2018 Gas sales $ 935 $ — $ 12 $ 947 Oil sales 78 — 1 79 NGL sales 140 — — 140 Marketing — 1,557 (1,039 ) 518 Gas gathering (1) — 136 (88 ) 48 Other (2) 4 — — 4 Total $ 1,157 $ 1,693 $ (1,114 ) $ 1,736 (1) The Company’s gas gathering assets were divested in December 2018 as part of the Fayetteville Shale sale. (2) Other E&P revenues consists primarily of water sales to third-party operators, and other Midstream revenues consists primarily of sales of gas from storage. Associated E&P revenues are also disaggregated for analysis on a geographic basis by the core areas in which the Company operates, which are in Pennsylvania and West Virginia. In December 2018, the Company sold 100% of its Fayetteville Shale assets. For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Northeast Appalachia $ 217 $ 213 $ 565 $ 540 Southwest Appalachia 153 166 346 322 Fayetteville Shale — 139 — 291 Other 1 2 2 4 Total $ 371 $ 520 $ 913 $ 1,157 Receivables from Contracts with Customers The following table reconciles the Company’s receivables from contracts with customers to consolidated accounts receivable as presented on the consolidated balance sheet: (in millions) June 30, 2019 December 31, 2018 Receivables from contracts with customers $ 238 $ 494 Other accounts receivable 120 87 Total accounts receivable $ 358 $ 581 Amounts recognized against the Company’s allowance for doubtful accounts related to receivables arising from contracts with customers were immaterial for the three and six months ended June 30, 2019 and 2018 . The Company has no contract assets or contract liabilities associated with its revenues from contracts with customers.

Cash and Cash Equivalents

Cash and Cash Equivalents	6 Months Ended
	Jun. 30, 2019
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	CASH AND CASH EQUIVALENTS The following table presents a summary of cash and cash equivalents as of June 30, 2019 and December 31, 2018 : (in millions) June 30, 2019 December 31, 2018 Cash $ 71 $ 32 Marketable securities (1) 69 169 Other cash equivalents (2) 15 — Total $ 155 $ 201 (1) Consists of government stable value money market funds. (2) Consists of time deposits.

Natural Gas and Oil Properties

Natural Gas and Oil Properties	6 Months Ended
	Jun. 30, 2019
Oil and Gas Exploration and Production Industries Disclosures [Abstract]
Natural Gas and Oil Properties	NATURAL GAS AND OIL PROPERTIES The Company utilizes the full cost method of accounting for costs related to the exploration, development and 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, are 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 , including 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 of $3.02 per MMBtu, West Texas Intermediate oil of $61.39 per barrel and NGLs of $16.35 per 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 at June 30, 2019 . The Company had no derivative positions that were designated for hedge accounting as of June 30, 2019 . 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 $2.92 per MMBtu, West Texas Intermediate oil of $54.15 per barrel and NGLs of $15.56 per 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 at June 30, 2018 . The Company had no derivative positions that were designated for hedge accounting as of June 30, 2018 .

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE Basic earnings per common share is computed by dividing net income 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 January 2015, the Company issued 34,500,000 depositary shares that entitled the holder to a proportional fractional interest in the rights and preferences of the mandatory convertible preferred stock, including conversion, dividend, liquidation and voting rights. The mandatory convertible preferred stock had 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, therefore, was considered a participating security. Accordingly, it has been 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, earnings are allocated to participating securities 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 January 12, 2018 , all outstanding shares of mandatory convertible preferred stock converted to 74,998,614 shares of the Company’s common stock. The Company paid out its last dividend payment of approximately $27 million associated with the depositary shares in January 2018. During the second half of 2018 , the Company repurchased 39,061,269 shares of its outstanding common stock for approximately $180 million at an average price of $4.63 per share. In the first quarter of 2019, the Company completed its share repurchase program by purchasing 5,260,687 shares of its outstanding common stock for approximately $ 21 million at an average price of $ 3.84 per share. The following table presents the computation of earnings per share for the three and six months ended June 30, 2019 and 2018 :  For the three months ended June 30, For the six months ended June 30, (in millions, except share/per share amounts) 2019 2018 2019 2018 Net income $ 138 $ 51 $ 732 $ 259 Participating securities - mandatory convertible preferred stock — — — 2 Net income attributable to common stock $ 138 $ 51 $ 732 $ 257  Number of common shares: Weighted average outstanding 539,005,941 581,159,200 539,362,984 576,255,744 Issued upon assumed exercise of outstanding stock options — — — — Effect of issuance of non-vested restricted common stock 311,732 480,580 481,948 683,562 Effect of issuance of non-vested performance units 629,380 1,238,326 779,810 1,283,434 Weighted average and potential dilutive outstanding 539,947,053 582,878,106 540,624,742 578,222,740  Earnings per common share Basic $ 0.26 $ 0.09 $ 1.36 $ 0.45 Diluted $ 0.26 $ 0.09 $ 1.35 $ 0.44 The following table presents the common stock shares equivalent excluded from the calculation of diluted earnings per share for the three and six months ended June 30, 2019 and 2018 , as they would have had an antidilutive effect:  For the three months ended June 30, For the six months ended June 30,  2019 2018 2019 2018 Unexercised stock options 5,114,763 — 5,121,663 — Unvested share-based payment 1,773,074 4,335,715 1,822,346 5,152,847 Performance units 241,896 875,800 250,998 986,585 Mandatory convertible preferred stock — — — 4,972,284 Total 7,129,733 5,211,515 7,195,007 11,111,716

Derivatives and Risk Management

Derivatives and Risk Management	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Risk Management	DERIVATIVES AND RISK MANAGEMENT The Company is exposed to volatility in market prices and basis differentials 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 derivative financial instruments. As of June 30, 2019 , the Company’s derivative financial instruments consisted of fixed price swaps, two-way costless collars, three-way costless collars, basis swaps, call options and interest rate swaps. A description of the Company’s derivative financial instruments is provided below: Fixed price swaps If the Company sells a fixed price swap, the Company receives a fixed price for the contract and pays a floating market price to the counterparty. If the Company purchases a fixed price swap, the Company receives a floating market price for the contract and pays a fixed price to the counterparty.  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. If the Company sells a basis swap, 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. If the Company purchases a basis swap, the Company pays the counterparty if the price differential is greater than the stated terms of the contract and receives a payment from the counterparty if the price differential is less than the stated terms of the contract.  Call options The Company purchases and sells call options in exchange for a premium. If the Company purchases a call option, the Company receives from the counterparty the excess (if any) of the market price over the strike price of the call option at the time of settlement, but if the market price is below the call’s strike price, no payment is due from either party. If the Company sells a call option, the Company pays the counterparty the excess (if any) of the market price over the strike price of the call option at the time of settlement, but if the market price is 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 unfavorable interest rate changes. The Company chooses counterparties for its derivative instruments that it believes are creditworthy at the time the transactions are entered into, and the Company actively monitors the credit ratings and credit default swap rates of these counterparties where applicable. However, there can be no assurance that a counterparty will be able to meet its obligations to the Company. The Company presents its derivative positions on a gross basis and does not net the asset and liability positions. As part of the Fayetteville Shale sale, the Company entered into certain natural gas derivative positions that were subsequently novated to the buyer in conjunction with finalization of the sale. The derivatives that were novated to the buyer are not included in the tables below. The following tables provide 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 tables present the notional amount, the weighted average contract prices and the fair value by expected maturity dates as of June 30, 2019 : Financial Protection on Production  Weighted Average Price per MMBtu  Volume (Bcf) Swaps Sold Puts Purchased Puts Sold Calls Basis Differential Fair Value at June 30, 2019 (in millions) Natural Gas 2019 Fixed price swaps 131 $ 2.92 $ — $ — $ — $ — $ 75 Two-way costless collars 25 — — 2.78 2.92 — 13 Three-way costless collars 67 — 2.47 2.88 3.22 — 22 Total 223 $ 110 2020 Fixed price swaps 24 $ 2.88 $ — $ — $ — $ — $ 8 Three-way costless collars 148 — 2.36 2.67 2.97 — 10 Total 172 $ 18 2021 Three-way costless collars 37 $ — $ 2.35 $ 2.60 $ 2.93 $ — $ (1 )  Basis Swaps 2019 80 $ — $ — $ — $ — $ (0.45 ) $ (6 ) 2020 132 — — — — (0.34 ) (10 ) 2021 28 — — — — (0.51 ) (1 ) Total 240 $ (17 )  Volume (MBbls) Weighted Average Strike Price per Bbl Fair Value at June 30, 2019 (in millions) Swaps Sold Puts Purchased Puts Sold Calls Oil 2019 Fixed price swaps (1) 1,003 $ 60.89 $ — $ — $ — $ 4 Two-way costless collars 764 — — 61.45 67.16 4 Three-way costless collars 276 — 45.00 55.00 63.67 — Total 2,043 $ 8 2020 Fixed price swaps 1,556 $ 60.18 $ — $ — $ — $ 7 Two-way costless collars 366 — — 60.00 69.80 3 Three-way costless collars 641 — 45.00 55.00 63.36 1 Total 2,563 $ 11 Propane 2019 Fixed price swaps 1,955 $ 30.18 $ — $ — $ — $ 14 Two-way costless collars 276 — — 25.62 28.77 1 Total 2,231 $ 15 2020 Fixed price swaps 2,196 $ 26.97 $ — $ — $ — $ 6 Two-way costless collars 366 — — 25.20 $ 29.40 1 Total 2,562 $ 7  Ethane 2019 Fixed price swaps 1,858 $ 13.90 $ — $ — $ — $ 10 2020 Fixed price swaps 732 $ 13.49 $ — $ — $ — $ 2 (1) Includes 138 MBbls of purchased fixed price oil swaps hedged at $69.10 per barrel with a fair value of ($1) million and 1,141 MBbls of sold fixed price oil swaps hedged at $61.88 with a fair value of $5 million . Other Derivative Contracts  Volume (Bcf) Weighted Average Strike Price per MMBtu Fair Value at June 30, 2019 (in millions) Purchased Call Options – Natural Gas 2019 17 $ 3.50 $ — 2020 68 3.63 2 2021 57 3.52 2 Total 142 $ 4  Sold Call Options – Natural Gas 2019 26 $ 3.50 $ — 2020 137 3.39 (8 ) 2021 114 3.33 (8 ) Total 277 $ (16 ) ໿  Volume (Bcf) Weighted Average Strike Price per MMBtu Basis Differential per MMBtu Fair Value at June 30, 2019 ($ in millions) Storage (1) 2019 Purchased fixed price swaps 1 $ 2.87 $ — $ (1 ) Purchased basis swaps 1 — (0.53 ) — Total 2 $ (1 ) 2020 Fixed price swap 1 $ 3.14 $ — $ — (1) The Company has entered into certain derivatives to protect the value of volumes of natural gas injected into a storage facility that will be withdrawn at a later date. At June 30, 2019 , the net fair value of the Company’s financial instruments related to commodities was a $150 million asset . The net fair value of the Company’s interest rate swaps was a $1 million liability as of June 30, 2019 . As of June 30, 2019 , the Company had no positions designated for hedge accounting treatment. Gains and losses on derivatives that are not designated for hedge accounting treatment, or do not meet hedge accounting requirements, are recorded as a component of gain (loss) on derivatives on the consolidated statements of operations. Accordingly, the gain (loss) on derivatives component of the statement of operations reflects the gain 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 on the consolidated statements 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) is summarized below as of June 30, 2019 and December 31, 2018 : Derivative Assets  Fair Value (in millions) Balance Sheet Classification June 30, 2019 December 31, 2018 Derivatives not designated as hedging instruments: Fixed price swaps – natural gas Derivative assets $ 79 $ 32 Fixed price swaps – oil Derivative assets 7 13 Fixed price swaps – propane Derivative assets 18 11 Fixed price swaps – ethane Derivative assets 11 7 Two-way costless collars – natural gas Derivative assets 13 11 Two-way costless collars – oil Derivative assets 6 6 Two-way costless collars – propane Derivative assets 2 — Three-way costless collars – natural gas Derivative assets 65 41 Three-way costless collars – oil Derivative assets 2 — Basis swaps – natural gas Derivative assets 5 8 Purchased call options – natural gas Derivative assets 1 (1) — Interest rate swaps Derivative assets — 1 Fixed price swaps – natural gas Other long-term assets 4 6 Fixed price swaps – oil Other long-term assets 4 6 Fixed price swaps – propane Other long-term assets 2 — Fixed price swaps – ethane Other long-term assets 1 1 Two-way costless collars – oil Other long-term assets 2 5 Three-way costless collars – natural gas Other long-term assets 31 34 Three-way costless collars – oil Other long-term assets 2 — Basis swaps – natural gas Other long-term assets 2 3 Purchased call options – natural gas Other long-term assets 4 6 Total derivative assets $ 261 $ 191 Derivative Liabilities  Fair Value (in millions) Balance Sheet Classification June 30, 2019 December 31, 2018 Derivatives not designated as hedging instruments: Purchased fixed price swap – oil Derivative liabilities $ 1 $ 6 Fixed price swaps – natural gas Derivative liabilities — 9 Fixed price swaps – ethane Derivative liabilities — 3 Two-way costless collars – natural gas Derivative liabilities — 7 Two-way costless collars – oil Derivative liabilities 1 — Three-way costless collars – natural gas Derivative liabilities 37 33 Three-way costless collars – oil Derivative liabilities 2 — Basis swaps – natural gas Derivative liabilities 19 18 Sold call options – natural gas Derivative liabilities 5 3 Storage – fixed price swap Derivative liabilities 1 — Interest rate swaps Derivative liabilities 1 — Fixed price swaps – natural gas Other long-term liabilities — 1 Two-way costless collars – oil Other long-term liabilities — 1 Three-way costless collars – natural gas Other long-term liabilities 28 35 Three-way costless collars – oil Other long-term liabilities 1 — Basis swap – natural gas Other long-term liabilities 5 4 Sold call options – natural gas Other long-term liabilities 11 19 Total derivative liabilities $ 112 $ 139 (1) Includes $1 million in premiums paid related to certain natural gas purchased call options recognized as a component of derivative assets within current assets on the consolidated balance sheet at June 30, 2019 . As certain natural gas purchased call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the consolidated statements of operations. The following tables summarize the before-tax effect of the Company’s derivative instruments on the consolidated statements of operations for the three and six months ended June 30, 2019 and 2018 : Unsettled Gain (Loss) on Derivatives Recognized in Earnings Derivative Instrument Consolidated Statement of Operations Classification of Gain (Loss) on Derivatives, Unsettled For the three months ended June 30, For the six months ended June 30, 2019 2018 2019 2018  (in millions) Purchased fixed price swaps – oil Gain (Loss) on Derivatives $ 1 $ — $ 5 $ — Fixed price swaps – natural gas Gain (Loss) on Derivatives 57 (26 ) 55 (29 ) Fixed price swaps – oil Gain (Loss) on Derivatives 5 — (8 ) — Fixed price swaps – propane Gain (Loss) on Derivatives 13 (12 ) 9 (9 ) Fixed price swaps – ethane Gain (Loss) on Derivatives — (2 ) 7 (2 ) Two-way costless collars – natural gas Gain (Loss) on Derivatives 10 (1 ) 9 2 Two-way costless collars – oil Gain (Loss) on Derivatives 4 — (3 ) — Two-way costless collars – propane Gain (Loss) on Derivatives 2 — 2 — Three-way costless collars – natural gas Gain (Loss) on Derivatives 22 (24 ) 24 (29 ) Three-way costless collars – oil Gain (Loss) on Derivatives 1 — 1 — Basis swaps – natural gas Gain (Loss) on Derivatives 4 (4 ) (6 ) 16 Purchased call options – natural gas Gain (Loss) on Derivatives (2 ) (12 ) (2 ) 4 Sold call options – natural gas Gain (Loss) on Derivatives 4 31 6 (3 ) Sold call options – oil Gain (Loss) on Derivatives — (6 ) — (6 ) Storage – fixed price swap Gain (Loss) on Derivatives (1 ) — (1 ) — Interest rate swaps Gain (Loss) on Derivatives (2 ) — (2 ) 2 Total gain (loss) on unsettled derivatives $ 118 $ (56 ) $ 96 $ (54 ) Settled Gain (Loss) on Derivatives Recognized in Earnings (1) Derivative Instrument Consolidated Statement of Operations Classification of Gain (Loss) on Derivatives, Settled For the three months ended June 30, For the six months ended June 30, 2019 2018 2019 2018 (in millions) Purchased fixed price swaps – oil Gain (Loss) on Derivatives $ (1 ) $ — $ (2 ) $ — Sold fixed price swaps – natural gas Gain (Loss) on Derivatives 14 13 8 13 Sold fixed price swaps – oil Gain (Loss) on Derivatives 2 — 4 — Sold fixed price swaps – propane Gain (Loss) on Derivatives 7 (1 ) 9 (1 ) Sold fixed price swaps – ethane Gain (Loss) on Derivatives 5 — 6 — Two-way costless collars – natural gas Gain (Loss) on Derivatives 3 — 2 4 Two-way costless collars – oil Gain (Loss) on Derivatives 1 — 2 — Three-way costless collars – natural gas Gain (Loss) on Derivatives 8 12 4 19 Sold basis swaps – natural gas Gain (Loss) on Derivatives (4 ) (3 ) (8 ) (24 ) Purchased call options – natural gas Gain (Loss) on Derivatives — — — 2 (2) Sold call options – natural gas Gain (Loss) on Derivatives (1 ) — (1 ) (1 ) Sold call options – oil Gain (Loss) on Derivatives — (1 ) — (1 ) Total gain on settled derivatives $ 34 $ 20 $ 24 $ 11  Total gain (loss) on derivatives $ 152 $ (36 ) $ 120 $ (43 ) (1) The Company calculates gain (loss) on derivatives, settled, as the summation of gains and losses on positions that settled within the period. (2) Includes $1 million amortization of premiums paid related to certain natural gas call options for the six months ended June 30, 2018 , which is included in gain (loss) on derivatives on the consolidated statements of operations.

Reclassifications from Accumula

Reclassifications from Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Reclassifications from Accumulated Other Comprehensive Income (Loss)	RECLASSIFICATIONS FROM ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) In the first half of 2019, changes in accumulated other comprehensive income primarily related to settlements in the Company’s pension and other postretirement benefits. The following tables detail the components of accumulated other comprehensive income and the related tax effects for the six months ended June 30, 2019 : (in millions) Pension and Other Postretirement Foreign Currency Total Beginning balance December 31, 2018 $ (22 ) $ (14 ) $ (36 ) Other comprehensive income before reclassifications — — — Amounts reclassified from other comprehensive income (1) 4 — 4 Net current-period other comprehensive income 4 — 4 Ending balance June 30, 2019 $ (18 ) $ (14 ) $ (32 ) (1) See separate table below for details about these reclassifications. Details about Accumulated Other Affected Line Item in the Amount Reclassified from Accumulated Other Comprehensive Income For the six months ended (in millions) Pension and other postretirement: Amortization of prior service cost and net loss (1) Other Income, Net $ 5 Provision for income taxes 1 Net income $ 4 Total reclassifications for the period Net income $ 4 ໿ (1) See Note 15 for additional details regarding the Company’s pension and other postretirement benefit plans.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Assets and liabilities measured at fair value on a recurring basis The carrying amounts and estimated fair values of the Company’s financial instruments as of June 30, 2019 and December 31, 2018 were as follows:  June 30, 2019 December 31, 2018 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Cash and cash equivalents $ 155 $ 155 $ 201 $ 201 2018 revolving credit facility due April 2023 — — — — Senior notes (1) 2,342 2,220 2,342 2,190 Derivative instruments, net 149 (2) 149 (2) 52 52 (1) Excludes unamortized debt issuance costs and debt discounts. (2) Includes $1 million in premiums paid related to certain natural gas purchased call options recognized as a component of derivative assets within current assets on the consolidated balance sheet. 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 calculation of fair market value. Level 3 valuations - Consist of internal estimates and have the lowest priority. The carrying values of cash and cash equivalents, including marketable securities, accounts receivable, other current assets, accounts payable and other current liabilities on the consolidated balance sheets approximate 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 market prices of the Company’s senior notes. These instruments were previously classified as a Level 2 measurement but substantially all senior notes were updated to a Level 1 measurement in the second quarter of 2018 as the market activity of the Company’s debt has resulted in timely quoted prices. The 4.05% Senior Notes due January 2020 remain a Level 2 measurement due to relative market inactivity. The carrying values of the borrowings under the Company’s revolving credit facility (to the extent utilized) approximates fair value because the interest rate is variable and reflective of market rates. The Company considers the fair value of its revolving credit facility to be a Level 1 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 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 for natural gas and oil derivatives and Oil Price Information Service (“OPIS”) for ethane and propane derivatives. The Company utilizes discounted cash flow models for valuing its interest rate derivatives (Level 2). The net derivative values attributable to the Company’s interest rate derivative contracts as of June 30, 2019 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, two-way costless collars and three-way costless collars (Level 2) 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 and OPIS futures index, interest rates, volatility and credit worthiness. The Company’s basis swaps (Level 2) are estimated using third-party calculations based upon forward commodity price curves. These instruments were previously classified as a Level 3 measurement in the fair value hierarchy but were updated to a Level 2 measurement in the second quarter of 2018 as a result of the Company’s ability to derive volatility inputs and forward commodity price curves from directly observable sources. Inputs to the Black-Scholes model, including the volatility input, 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:  June 30, 2019  Fair Value Measurements Using: (in millions) Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value Assets Fixed price swap – natural gas $ — $ 83 $ — $ 83 Fixed price swap – oil — 11 — 11 Fixed price swap – propane — 20 — 20 Fixed price swap – ethane — 12 — 12 Two-way costless collar – natural gas — 13 — 13 Two-way costless collar – oil — 8 — 8 Two-way costless collar – propane — 2 — 2 Three-way costless collar – natural gas — 96 — 96 Three-way costless collar – oil — 4 — 4 Basis swap – natural gas — 7 — 7 Purchased call option – natural gas (1) — 5 — 5 Liabilities Purchased fixed price swap – oil — (1 ) — (1 ) Two-way costless collar – oil — (1 ) — (1 ) Three-way costless collar – natural gas — (65 ) — (65 ) Three-way costless collar – oil — (3 ) — (3 ) Basis swap – natural gas — (24 ) — (24 ) Sold call option – natural gas — (16 ) — (16 ) Storage – fixed price swap — (1 ) — (1 ) Interest rate swap — (1 ) — (1 ) Total $ — $ 149 $ — $ 149 (1) Includes $1 million in premiums paid related to certain natural gas purchased call options recognized as a component of derivative assets within current assets on the consolidated balance sheet at June 30, 2019 . As certain natural gas purchased call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the consolidated statements of operations.  December 31, 2018  Fair Value Measurements Using: (in millions) Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value Assets Fixed price swap – natural gas $ — $ 38 $ — $ 38 Fixed price swap – oil — 19 — 19 Fixed price swap – propane — 11 — 11 Fixed price swap – ethane — 8 — 8 Two-way costless collar – natural gas — 11 — 11 Two-way costless collar – oil — 11 — 11 Three-way costless collar – natural gas — 75 — 75 Basis swap – natural gas — 11 — 11 Purchased call option – natural gas — 6 — 6 Interest rate swap — 1 — 1 Liabilities Purchased fixed price swap – oil — (6 ) — (6 ) Fixed price swap – natural gas — (10 ) — (10 ) Fixed price swap – ethane — (3 ) — (3 ) Two-way costless collar – natural gas — (7 ) — (7 ) Two-way costless collar – oil — (1 ) — (1 ) Three-way costless collar – natural gas — (68 ) — (68 ) Basis swap – natural gas — (22 ) — (22 ) Sold call option – natural gas — (22 ) — (22 ) Total $ — $ 52 $ — $ 52 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 unobservable inputs (Level 3) for the three and six months ended June 30, 2019 and 2018 . The fair values of Level 3 derivative instruments were estimated using proprietary valuation models that utilized both market observable and unobservable parameters. Level 3 instruments presented in the table consisted of net derivatives valued using pricing models incorporating assumptions that, in the Company’s judgment, reflected reasonable assumptions a marketplace participant would have used as of June 30, 2018 . Commodity derivatives previously presented as Level 3 were transferred to Level 2 in the second quarter of 2018 as the Company moved from using proprietary volatility inputs and forward curves to more widely available published information, increasing market observability. ໿  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ — $ 22 $ — $ 22 Total gains (losses): Included in earnings — (8 ) — (17 ) Settlements — (8 ) — 1 (1) Transfers into/out of Level 3 — (6 ) (2) — (6 ) (2) Balance at end of period $ — $ — $ — $ — Change in gains (losses) included in earnings relating to derivatives still held as of June 30 $ — $ — $ — $ — (1) Includes $1 million amortization of premiums paid related to certain natural gas call options for the six months ended June 30, 2018 . (2) Commodity derivatives previously presented as Level 3 were transferred to Level 2 in the second quarter of 2018 as the Company moved from using proprietary volatility inputs and forward curves to more widely available published information, increasing market observability.

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	DEBT The components of debt as of June 30, 2019 and December 31, 2018 consisted of the following: June 30, 2019 (in millions) Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total Current portion of long-term debt: 4.05% Senior Notes due January 2020 (1) $ 52 $ — $ — $ 52 Total current portion of long-term debt $ 52 $ — $ — $ 52 Long-term debt: Variable rate (3.880% at June 30, 2019) 2018 revolving credit facility, due April 2023 $ — $ — (2) $ — $ — 4.10% Senior Notes due March 2022 213 (1 ) — 212 4.95% Senior Notes due January 2025 (1) 927 (7 ) (1 ) 919 7.50 % Senior Notes due April 2026 650 (8 ) — 642 7.75 % Senior Notes due October 2027 500 (6 ) — 494 Total long-term debt $ 2,290 $ (22 ) $ (1 ) $ 2,267 Total debt $ 2,342 $ (22 ) $ (1 ) $ 2,319 December 31, 2018 (in millions) Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total Long-term debt: Variable rate (3.920% at December 31, 2018) 2018 term loan facility, due April 2023 $ — $ — (2) $ — $ — 4.05% Senior Notes due January 2020 (1) 52 — — 52 4.10% Senior Notes due March 2022 213 (1 ) — 212 4.95% Senior Notes due January 2025 (1) 927 (7 ) (1 ) 919 7.50% Senior Notes due April 2026 650 (8 ) — 642 7.75% Senior Notes due October 2027 500 (7 ) — 493 Total long-term debt $ 2,342 $ (23 ) $ (1 ) $ 2,318 (1) 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 5.80% for the 2020 Notes and 6.70% for the 2025 Notes. In April and May 2018, S&P and Moody’s upgraded certain senior notes. As a result of these upgrades, interest rates decreased to 5.30% for the 2020 Notes and 6.20% for the 2025 Notes effective July 2018 . The first coupon payment to the bondholders at the lower interest rate was paid in January 2019 . (2) At June 30, 2019 and December 31, 2018 , unamortized issuance expense of $10 million and $11 million , respectively, associated with the 2018 revolving credit facility is classified as other long-term assets on the consolidated balance sheets. Credit Facilities 2018 Revolving Credit Facility In April 2018 , the Company replaced its 2016 credit facility (which consisted of a $1,191 million secured term loan and an unsecured $743 million revolving credit facility) with a new revolving credit facility (the “2018 credit facility”). Concurrent with the closing of the 2018 credit facility agreement on April 26, 2018, the Company repaid the $1,191 million secured term loan balance and recognized a loss on early debt extinguishment of $8 million on the consolidated income statement related to the unamortized issuance expense. In addition, approximately $4 million of unamortized issuance expense associated with the closed $743 million revolving credit facility was carried forward into the unamortized issuance expenses of the 2018 credit facility. The 2018 credit facility has an aggregate maximum revolving credit amount of $3.5 billion and, at June 30, 2019 , had a current borrowing base of $2.1 billion with a current aggregate commitment of $2.0 billion . The borrowing base is subject to redetermination twice a year in April and October. On April 4, 2019 , the banks participating in the 2018 credit facility reaffirmed the borrowing base of $2.1 billion . The permitted lien provisions in the senior note indentures currently limit liens securing indebtedness to the greater of $2.0 billion and 25% of adjusted consolidated net tangible assets. The 2018 credit facility matures in April 2023 and is secured by substantially all of the assets owned by the Company and its subsidiaries. Loans under the 2018 credit facility 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 for such interest period plus the applicable margin (as those terms are defined in the 2018 credit facility documentation). The applicable margin for Eurodollar loans under the 2018 credit facility ranges from 1.50% to 2.50% based on the Company’s utilization of the borrowing base under the 2018 credit facility. Alternate base rate loans bear interest at the alternate base rate plus the applicable margin. The applicable margin for alternate base rate loans under the 2018 credit facility ranges from 0.50% to 1.50% based on the Company’s utilization of the borrowing base under the 2018 credit facility. The 2018 credit facility contains customary representations and warranties and contains covenants including, among others, the following: • a prohibition against incurring debt, subject to permitted exceptions; • a restriction on creating liens on assets, subject to permitted exceptions; • restrictions on mergers and asset dispositions; • restrictions on use of proceeds, investments, transactions with affiliates, or change of principal business; and • maintenance of the following financial covenants, commencing with the fiscal quarter ending June 30, 2018: 1. Minimum current ratio of no less than 1.00 to 1.00, whereby current ratio is defined as the Company’s consolidated current assets (including unused commitments under the credit agreement, but excluding non-cash derivative assets) to consolidated current liabilities (excluding non-cash derivative obligations and current maturities of long-term debt). 2. Maximum total net leverage ratio of no greater than (i) with respect to each fiscal quarter ending during the period from June 30, 2018 through March 31, 2019, 4.50 to 1.00, (ii) with respect to each fiscal quarter ending during the period from June 30, 2019 through March 31, 2020, 4.25 to 1.00, and (iii) with respect to each fiscal quarter ending on or after June 30, 2020, 4.00 to 1.00. Total net leverage ratio is defined as total debt less cash on hand (up to the lesser of 10% of credit limit or $150 million ) divided by consolidated EBITDAX for the last four consecutive quarters. EBITDAX, as defined in the Company’s 2018 credit agreement, excludes the effects of interest expense, depreciation, depletion and amortization, income tax, 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. The 2018 credit facility contains customary events of default that include, among other things, the failure to comply with the financial covenants described above, non-payment of principal, interest or fees, violation of covenants, inaccuracy of representations and warranties, bankruptcy and insolvency events, material judgments and cross-defaults to material indebtedness. If an event of default occurs and is continuing, all amounts outstanding under the 2018 credit facility may become immediately due and payable. As of June 30, 2019 , the Company was in compliance with all of the covenants of the credit agreement. Each United States domestic subsidiary of the Company for which the Company owns 100% guarantees the 2018 credit facility. Pursuant to requirements under the indentures governing its senior notes, each subsidiary that became a guarantor of the 2018 credit facility also became a guarantor of each of the Company’s senior notes. See Note 19 for the Company’s Condensed Consolidated Financial Information, presented in accordance with Rule 3-10 of Regulation S-X. As of June 30, 2019 , the Company had $172 million in letters of credit and no borrowings outstanding under the 2018 revolving credit facility. Senior Notes In January 2015 , the Company completed a public offering of $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 2020 Notes, the “Notes”). 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 5.80% 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 6.05% and 6.95% , respectively. The first coupon payment to the bondholders at the higher interest rates was paid in January 2017 . S&P and Moody’s upgraded the Notes in April and May 2018, respectively. As a result of these upgrades, interest rates decreased to 5.30% for the 2020 Notes and 6.20% for the 2025 Notes effective July 2018 . The first coupon payment to the bondholders at the lower interest rates was paid in January 2019 .

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Operating Commitments and Contingencies As of June 30, 2019 , 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 approximately $8.5 billion , $966 million 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. The Company also had guarantee obligations of up to $362 million of that amount. As of June 30, 2019 , future payments under non-cancelable firm transportation and gathering agreements were as follows:  Payments Due by Period (in millions) Total Less than 1 Year 1 to 3 Years 3 to 5 Years 5 to 8 Years More than 8 Years Infrastructure currently in service $ 7,501 $ 702 $ 1,304 $ 1,097 $ 1,511 $ 2,887 Pending regulatory approval and/or construction (1) 966 9 78 121 196 562 Total transportation charges $ 8,467 $ 711 $ 1,382 $ 1,218 $ 1,707 $ 3,449 (1) Based on estimated in-service dates as of June 30, 2019 . In December 2018 , the Company closed on the Fayetteville Shale sale. The Company retained certain contractual commitments related to firm transportation, with the buyer obligated to pay the transportation provider directly for these charges. As of June 30, 2019 , approximately $162 million of these contractual commitments remain of which the Company will reimburse the buyer for certain of these potential obligations up to approximately $82 million through 2020 depending on the buyer’s actual use, and has recorded a $68 million liability for the estimated future payments, down from $88 million recorded at December 31, 2018 . In the first quarter of 2019, the Company agreed to purchase firm transportation with pipelines in the Appalachian Basin starting in 2021 and running through 2032 totaling $357 million in total contractual commitments, which is presented in the table above; the seller has agreed to reimburse $133 million of these commitments. In July 2019 the Company terminated its existing lease agreement and entered into a new lease agreement for a smaller portion of the headquarters office building, resulting in a contractual commitment totaling $88 million over the next ten years . Environmental 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, results of operations or cash flows of the Company. Litigation 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, pollution, contamination, encroachment on others’ property or nuisance. The Company accrues for such items when a liability is both probable and the amount can be reasonably estimated. It is not possible at this time to estimate the amount of any additional loss, or range of loss, that is reasonably possible, but, based on the nature of the claims, 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, 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 inherent uncertainties; therefore, management’s view may change in the future. Arkansas Royalty Litigation The Company has been a defendant in three certified class actions alleging that the Company 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. Two of the these class actions were filed in Arkansas state courts and the third in the United States District Court for the Eastern District of Arkansas. The Company denied liability in all these cases. Under the agreement for the sale of the equity in the Company’s subsidiaries that operated in the Fayetteville Shale, the Company retained responsibility for these class actions. In June 2017, the jury returned a verdict in favor of the Company on all counts in Smith v. SEECO, Inc. et al. , the class action in the federal court, whose plaintiff class comprises the vast majority of the lessors in these cases. The plaintiff had 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 judgment in favor of the Company on all claims. The trial court denied the plaintiff’s motion for a new trial, and the plaintiff appealed to the United States Court of Appeals for the Eighth Circuit. Independent of the plaintiff’s appeal, several different parties sought to intervene in the Smith case prior to or shortly after trial, and have appealed the trial court’s order denying their request to intervene. Oral argument occurred in January 2019. On April 23, 2019, the Court of Appeals affirmed the trial court’s order denying all requests to intervene in the case, and, in a separate order, affirmed the trial court’s judgment in favor of the Company on all claims. The Court of Appeals subsequently denied all requests for rehearing. In the second quarter of 2018, the Company entered into an agreement to settle another of the class actions, which has been pending in the Circuit Court of Conway County, Arkansas under the caption Snow et al. v. SEECO, Inc . , et al . The settlement received final approval by the court during the third quarter of 2018, and the deadline to appeal the order approving the settlement passed without any appeals filed. The amount of the settlement is reflected in the Company’s consolidated statement of operations for the second quarter of 2018 and was paid early in the fourth quarter of 2018. The third class action was dismissed in the second quarter of 2018. The Smith and the Snow cases cover all affected lessors, except a small percentage who opted out. Most of those have filed separate actions. The Company does not expect those cases to have a material adverse effect on the results of operations, financial position or cash flows of the Company. Additionally, it is not possible at this time to estimate the amount of any additional loss, or range of loss, that is reasonably possible. 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. The Company likewise obtains indemnification for future matters when it sells assets, although there is no assurance the buyer will be capable of performing those obligations. No material liabilities have been recognized in connection with these indemnifications.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income Taxes	INCOME TAXES The Company’s effective tax rate was approximately 10% and 0% for the three months ended June 30, 2019 and 2018 , respectively, and (128)% and 0% for the six months ended June 30, 2019 and 2018 , respectively, primarily as a result of the release of valuation allowances previously recorded against deferred tax assets. 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 assets 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. For the year ended December 31, 2018, the Company maintained a full valuation allowance against its deferred tax assets based on its conclusion, considering all available evidence (both positive and negative), that it was more likely than not that the deferred tax assets would not be realized. A significant item of objective negative evidence considered was the cumulative pre-tax loss incurred over the three-year period ended December 31, 2018, primarily due to impairments of proved natural gas and oil properties recognized in 2015 and 2016. As of the first quarter of 2019, the Company had sustained a three-year cumulative level of profitability. Based on this factor and other positive evidence including forecasted income, the Company concluded that it was more likely than not that the deferred tax assets would be realized and released substantially all of the valuation allowance. For the first half of 2019, the Company has recorded a discrete tax benefit of $411 million . The Company expects to retain a valuation allowance of $87 million related to net operating losses in jurisdictions in which it no longer operates.

Pension Plan and Other Postreti

Pension Plan and Other Postretirement Benefits	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Pension Plan and Other Postretirement Benefits	PENSION PLAN AND OTHER POSTRETIREMENT BENEFITS The Company maintains defined pension and other postretirement benefit plans, which cover substantially all of the Company’s employees. Net periodic pension costs include the following components for the three and six months ended June 30, 2019 and 2018 :  Pension Benefits  Consolidated Statements of Operations Classification of Net Periodic Benefit Cost For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Service cost General and administrative expenses $ 2 $ 3 $ 4 $ 6 Interest cost Other Income (Loss), Net 1 1 2 3 Expected return on plan assets Other Income (Loss), Net (1 ) (2 ) (3 ) (4 ) Amortization of prior service cost Other Income (Loss), Net — — — — Amortization of net loss Other Income (Loss), Net — — 1 — Settlement loss Other Income (Loss), Net 4 — 4 — Net periodic benefit cost $ 6 $ 2 $ 8 $ 5 The Company recognized a $4 million non-cash settlement loss related to $16 million of lump sum payments from the pension plan in the first half of 2019 for employees who were terminated as a result of the Fayetteville Shale sale. The Company’s other postretirement benefit plan had a net periodic benefit cost of less than $1 million and $1 million for the three months ended June 30, 2019 and 2018 , respectively, and a net periodic benefit cost of $1 million and $2 million for the six months ended June 30, 2019 and 2018 , respectively. As of June 30, 2019 , the Company has contributed $9 million to the pension and other postretirement benefit plans, and expects to contribute an additional $3 million to its pension plan during the remainder of 2019 . The Company recognized liabilities of $28 million and $13 million related to its pension and other postretirement benefits, respectively, as of June 30, 2019 , compared to liabilities of $34 million and $13 million as of December 31, 2018 , respectively. 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 Plan. Shares of the Company’s common stock purchased under the terms of the Non-Qualified Plan are included in treasury stock and totaled 5,115 shares and 10,653 shares at June 30, 2019 and December 31, 2018 , respectively.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2019
Share-based Compensation [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Company recognized the following amounts in total employee stock-based compensation costs for the three and six months ended June 30, 2019 and 2018 :  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Stock-based compensation cost – expensed $ 4 $ 8 $ 11 $ 13 Stock-based compensation cost – capitalized 2 4 6 7 The Company’s stock-based compensation is classified as either equity awards or liability awards in accordance with GAAP. The fair value of an equity-classified award is determined at the grant date and is amortized to general and administrative expense and capitalized expense on a straight-line basis over the vesting period of the award. The fair value of a liability-classified award is determined on a quarterly basis beginning at the grant date until final vesting. Changes in the fair value of liability-classified awards are recorded to general and administrative expense over the vesting period of the award. A portion of this general and administrative expense is capitalized into natural gas and oil properties, included in property and equipment. Generally, stock options granted to employees and directors vest ratably over three years from the grant date and expire seven years from the date of grant. The Company issues shares of restricted stock or restricted stock units to employees and directors which generally vest over four years . Restricted stock, restricted stock units and stock options granted to participants under the 2013 Incentive Plan, as amended and restated, immediately vest upon death, disability or retirement (subject to a minimum of three years of service). The Company issues performance unit awards to employees which historically have vested at or over three years . In December 2018, the Company closed the sale of the equity in certain of its subsidiaries that owned and operated its Fayetteville Shale E&P and related midstream gathering assets in Arkansas. As part of this transaction, most employees associated with those assets became employees of the buyer although the employment of some was or will be terminated. All affected employees were offered a severance package, which included a one-time cash payment depending on length of service and, if applicable, the current value of a portion of equity awards that were forfeited. Stock-based compensation costs recognized prior to the cancellation as either general and administrative expense or capitalized expense were reversed and the severance payments were subsequently recognized as restructuring charges for the year ended December 31, 2018 and the three months ended March 31, 2019 on the consolidated statements of operations. Equity-Classified Awards The Company recognized the following amounts in employee equity-classified stock-based compensation costs for the three and six months ended June 30, 2019 and 2018 :  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Equity-classified awards – expensed $ 2 $ 5 $ 4 $ 9 Equity-classified awards – capitalized 1 1 2 4 As of June 30, 2019 , there was $11 million of total unrecognized compensation cost related to the Company’s unvested equity-classified stock option grants, equity-classified restricted stock grants and equity-classified performance units. This cost is expected to be recognized over a weighted-average period of 1.3 years . Equity-Classified Stock Options The following table summarizes equity-classified stock option activity for the six months ended June 30, 2019 and provides information for options outstanding and options exercisable as of June 30, 2019 :  Number of Options Weighted Average Exercise Price  (in thousands) Outstanding at December 31, 2018 5,178 $ 17.06 Granted — $ — Exercised — $ — Forfeited or expired (72 ) $ 18.58 Outstanding at June 30, 2019 5,106 $ 17.04 Exercisable at June 30, 2019 4,590 $ 18.12 Equity-Classified Restricted Stock The following table summarizes equity-classified restricted stock activity for the six months ended June 30, 2019 and provides information for unvested shares as of June 30, 2019 :  Number of Shares Weighted Average Fair Value  (in thousands) Unvested shares at December 31, 2018 2,717 $ 7.91 Granted 15 $ 4.12 Vested (990 ) $ 7.37 Forfeited (175 ) $ 8.37 Unvested shares at June 30, 2019 1,567 $ 8.17 Equity-Classified Performance Units The following table summarizes equity-classified performance unit activity for the six months ended June 30, 2019 and provides information for unvested units as of June 30, 2019 . The performance unit awards granted in 2017 include a market condition based exclusively on the fair value of the Total Shareholder Return (“TSR”), as calculated by a Monte Carlo model. The total fair value of the performance units is amortized to compensation expense on a straight line basis over the vesting period of the award. The grant date fair value is calculated using the closing price of the Company’s common stock at the grant date.  Number of Shares (1) Weighted Average Fair Value  (in thousands) Unvested units at December 31, 2018 598 $ 10.01 Granted — $ — Vested (371 ) $ 9.73 Forfeited (30 ) $ 10.47 Unvested units at June 30, 2019 197 $ 10.47 (1) The actual payout of shares may range from a minimum of zero shares to a maximum of two shares per unit contingent upon TSR. 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 Awards The Company recognized the following amounts in employee liability-classified stock-based compensation costs for the three and six months ended June 30, 2019 :  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Liability-classified stock-based compensation cost – expensed $ 2 $ 3 $ 7 $ 4 Liability-classified stock-based compensation cost – capitalized 1 3 4 3 Liability-Classified Restricted Stock Units In the second quarters of 2019 and 2018 , the Company granted restricted stock units that vest over a period of four years and are payable in either cash or shares at the option of the Compensation Committee of the Company’s Board of Directors. The Company has accounted for these as liability-classified awards, and accordingly changes in the market value of the instruments will be recorded to general and administrative expense and capitalized expense over the vesting period of the award. As of June 30, 2019 , there was $38 million of total unrecognized compensation cost related to liability-classified restricted stock units that is expected to be recognized over a weighted-average period of 3.2 years . The amount of unrecognized compensation cost for liability-classified awards will fluctuate over time as they are marked to market.  Number of Units Weighted Average Fair Value  (in thousands) Unvested shares at December 31, 2018 8,202 $ 3.41 Granted 8,659 $ 4.34 Vested (2,617 ) $ 4.09 Forfeited (739 ) $ 3.13 Unvested units at June 30, 2019 13,505 $ 3.16 Liability-Classified Performance Units In the second quarters of 2019 and 2018 , the Company granted performance units that vest over a three-year period and are payable in either cash or shares at the option of the Compensation Committee of the Company’s Board of Directors. The Company has accounted for these as liability-classified awards, and accordingly changes in the fair market value of the instruments will be recorded to general and administrative expense and capitalized expense over the vesting period of the awards. The performance unit awards granted in 2018 include a performance condition based on cash flow per debt-adjusted share and two market conditions, one based on absolute TSR and the other on relative TSR as compared to a group of the Company’s peers. The performance unit awards granted in 2019 include a performance condition based on return on average capital employed and two market conditions, one based on absolute TSR and the other on relative TSR. The fair values of the two market conditions are calculated by Monte Carlo models on a quarterly basis. As of June 30, 2019 , there was $16 million of total unrecognized compensation cost related to liability-classified performance units. This cost is expected to be recognized over a weighted-average period of 2.4 years . The amount of unrecognized compensation cost for liability-classified awards will fluctuate over time as they are marked to market. The final value of the performance unit awards is contingent upon the Company’s actual performance against these performance measures.  Number of Shares Weighted Average Fair Value  (in thousands) Unvested shares at December 31, 2018 2,803 $ 3.41 Granted 2,757 $ 4.34 Vested — $ — Forfeited (119 ) $ 4.65 Unvested units at June 30, 2019 5,441 $ 3.16

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Information	SEGMENT 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 segment generates revenue through the marketing of both Company and third-party produced natural gas and liquids volumes. Prior to December 2018, the Midstream segment included the Company’s natural gas gathering business associated with its Fayetteville Shale assets. With the closing of the Fayetteville Shale sale in December 2018, the Company’s marketing business comprises substantially all of the Company’s Midstream segment. 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 2018 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 operating income, interest expense, gain (loss) on derivatives and other income (loss). The “Other” column includes items not related to the Company’s reportable segments, including real estate and corporate items.  E&P Midstream Other Total Three months ended June 30, 2019 (in millions) Revenues from external customers $ 380 $ 287 $ — $ 667 Intersegment revenues (9 ) 339 — 330 Depreciation, depletion and amortization expense 118 3 — 121 Operating income (loss) 30 (1) (8 ) — 22 Interest expense (2) 15 — — 15 Gain on derivatives 152 — — 152 Other loss, net (5 ) — (1 ) (6 ) Provision for income taxes (2) 15 — — 15 Assets 5,945 (3) 277 323 (4) 6,545 Capital investments (5) 367 — 1 368  Three months ended June 30, 2018 Revenues from external customers $ 527 $ 289 $ — $ 816 Intersegment revenues (7 ) 508 — 501 Depreciation, depletion and amortization expense 126 16 — 142 Operating income (6) 97 (1) 27 (7) — 124 Interest expense (2) 32 — — 32 Loss on derivatives (36 ) — — (36 ) Loss on early extinguishment of debt — — (8 ) (8 ) Other income, net 3 — — 3 Assets 5,583 (3) 1,228 231 (4) 7,042 Capital investments (5) 396 5 2 403 E&P Midstream Other Total Six months ended June 30, 2019 (in millions) Revenues from external customers $ 931 $ 726 $ — $ 1,657 Intersegment revenues (18 ) 841 — 823 Depreciation, depletion and amortization expense 228 5 — 233 Operating income (loss) 240 (1) (5 ) — 235 Interest expense (2) 29 — — 29 Gain on derivatives 120 — — 120 Other loss, net (4 ) — (1 ) (5 ) Benefit from income taxes (2) (411 ) — — (411 ) Assets 5,945 (3) 277 323 (4) 6,545 Capital investments (5) 692 — 1 693 Six months ended June 30, 2018 Revenues from external customers $ 1,170 $ 566 $ — $ 1,736 Intersegment revenues (13 ) 1,127 — 1,114 Depreciation, depletion and amortization expense 243 42 (8) — 285 Operating income (6) 335 (1) 44 (7) — 379 Interest expense (2) 71 — — 71 Loss on derivatives (43 ) — — (43 ) Loss on early extinguishment of debt — — (8 ) (8 ) Other income (loss), net 3 (1 ) — 2 Assets 5,583 (3) 1,228 231 (4) 7,042 Capital investments (5) 730 9 2 741 (1) Operating income for the E&P segment includes $2 million and $16 million of restructuring charges for the three months ended June 30, 2019 and 2018 , respectively, and $5 million and $16 million of restructuring charges for the six months ended June 30, 2019 and 2018 , respectively. (2) Interest expense and provision (benefit) for income taxes by segment is an allocation of corporate amounts as they are incurred at the corporate level. (3) E&P assets includes office, technology, water infrastructure, drilling rigs and other ancillary equipment not directly related to natural gas and oil properties. This also includes deferred tax assets which are an allocation of corporate amounts as they are incurred at the corporate level. (4) Other assets represent corporate assets not allocated to segments and assets for non-reportable segments. At June 30, 2019 and 2018 , other assets included approximately $155 million and $37 million , respectively, in cash and cash equivalents, $68 million and $89 million , respectively, in income taxes receivable, $50 million and $83 million , respectively, in property, plant and equipment, $10 million and $12 million , respectively, in unamortized debt expense, $6 million and $8 million , respectively, in a non-qualified retirement plan and $3 million , respectively, in other assets for both periods presented. Additionally, the June 30, 2019 asset balance includes $29 million in right-of-use lease assets. (5) Capital investments include increases of $39 million and $19 million for the three months ended June 30, 2019 and 2018 , respectively, and increases of $105 million and $52 million for the six months ended June 30, 2019 and 2018 , respectively, relating to the change in accrued expenditures between years. (6) Includes the impact of Fayetteville Shale-related E&P and Midstream operations which were divested on December 3, 2018. (7) Operating income for the Midstream segment includes $2 million related to restructuring charges for the three and six months ended June 30, 2018 . (8) Includes a $10 million impairment related to certain non-core gathering assets. Included in intersegment revenues of the Midstream segment are $339 million and $463 million for the three months ended June 30, 2019 and 2018 , respectively, and $841 million and $1,039 million for the six months ended June 30, 2019 and 2018 , respectively, for marketing of the Company’s E&P sales. Corporate assets include cash and cash equivalents, furniture and fixtures and other assets. Corporate general and administrative costs, depreciation expense and taxes, other than income taxes, are allocated to the segments.

New Accounting Pronouncements

New Accounting Pronouncements	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS New Accounting Standards Implemented 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. The codification was amended through additional ASUs. For public entities, Update 2016-02 became effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company adopted ASC 842 with an effective date of January 1, 2019 using the modified retrospective approach for all leases that existed at the date of initial application. The Company elected to apply the transition as of the beginning of the period of adoption. For leases that existed at the period of adoption on January 1, 2019, the incremental borrowing rate as of the application date was used to calculate the present value of remaining lease payments. Upon adoption of ASC 842, the Company recognized a discounted right-of-use asset and corresponding lease liability with opening balances of approximately $105 million as of January 1, 2019 . The adoption of the standard did not materially change the Company’s consolidated statement of operations or its consolidated statement of cash flows. Please refer to Note 4 – “Leases” for full disclosure. New Accounting Standards Not Yet Implemented In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“Update 2016-13”). Update 2016-13 replaces the incurred loss model with an expected loss model, which is referred to as the current expected credit loss (“CECL”) model. The CECL model is applicable to the measurement of credit losses on financial assets measured at amortized cost, including but not limited to trade receivables. The Company is still performing its evaluation of Update 2016-13, but does not believe it will have a material impact on its consolidated financial statements at this time.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	6 Months Ended
	Jun. 30, 2019
Condensed Financial Information Disclosure [Abstract]
Condensed Consolidating Financial Information	CONDENSED CONSOLIDATING FINANCIAL INFORMATION In April, 2018, the Company entered into the 2018 credit facility. Pursuant to requirements under the indentures governing the Company’s senior notes, each 100% owned subsidiary that became a guarantor of the 2018 credit facility also became a guarantor of each of the Company’s senior notes (the “Guarantor Subsidiaries”). The Guarantor Subsidiaries also granted liens and security interests to support their guarantees under the 2018 credit facility but not of the senior notes. These guarantees are full and unconditional and joint and several among the Guarantor Subsidiaries. Certain of the Company’s operating units which are accounted for on a consolidated basis do not guarantee the 2018 credit facility and senior notes (“Non-Guarantor Subsidiaries”). See Note 12 – Debt for additional information on the Company’s 2018 revolving credit facility and senior notes. At the closing of the Fayetteville Shale sale in December 2018, its subsidiaries being sold were released from these guarantees. See Note 2 for additional information on the divestiture of the Company’s Fayetteville Shale-related subsidiaries. The following financial information reflects consolidating financial information of Southwestern Energy Company (the parent and issuer company), its Guarantor Subsidiaries on a combined basis and the Non-Guarantor Subsidiaries on a combined basis, prepared on the equity basis of accounting. The information is presented in accordance with the requirements of Rule 3-10 under the SEC’s Regulation S-X. The financial information may not necessarily be indicative of results of operations, cash flows or financial position had the Guarantor Subsidiaries operated as independent entities. CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Three months ended June 30, 2019 Operating Revenues: Gas sales $ — $ 275 $ — $ — $ 275 Oil sales — 47 — — 47 NGL sales — 58 — — 58 Marketing — 287 — — 287 — 667 — — 667 Operating Costs and Expenses: Marketing purchases — 293 — — 293 Operating expenses — 169 — — 169 General and administrative expenses — 40 — — 40 Loss on sale of operating assets — 3 — — 3 Restructuring charges — 2 — — 2 Depreciation, depletion and amortization — 121 — — 121 Taxes, other than income taxes — 17 — — 17 — 645 — — 645 Operating Income — 22 — — 22 Interest Expense, Net 15 — — — 15 Gain on Derivatives — 152 — — 152 Other Loss, Net — (6 ) — — (6 ) Equity in Earnings of Subsidiaries 153 — — (153 ) — Income (Loss) Before Income Taxes 138 168 — (153 ) 153 Provision for Income Taxes — 15 — — 15 Net Income (Loss) $ 138 $ 153 $ — $ (153 ) $ 138 Net Income (Loss) $ 138 $ 153 $ — $ (153 ) $ 138 Other Comprehensive Income 4 — — — 4 Comprehensive Income (Loss) $ 142 $ 153 $ — $ (153 ) $ 142 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Three months ended June 30, 2018 Operating Revenues: Gas sales $ — $ 407 $ — $ — $ 407 Oil sales — 44 — — 44 NGL sales — 75 — — 75 Marketing — 265 — — 265 Gas gathering — 24 — — 24 Other — 1 — — 1 — 816 — — 816 Operating Costs and Expenses: Marketing purchases — 265 — — 265 Operating expenses — 193 — — 193 General and administrative expenses — 59 — — 59 Restructuring charges — 18 — — 18 Depreciation, depletion and amortization — 142 — — 142 Taxes, other than income taxes — 15 — — 15 — 692 — — 692 Operating Income — 124 — — 124 Interest Expense, Net 32 — — — 32 Loss on Derivatives — (36 ) — — (36 ) Loss on Early Extinguishment of Debt (8 ) — — — (8 ) Other Income, Net — 3 — — 3 Equity in Earnings of Subsidiaries 91 — — (91 ) — Income (Loss) Before Income Taxes 51 91 — (91 ) 51 Provision for Income Taxes — — — — — Net Income (Loss) $ 51 $ 91 $ — $ (91 ) $ 51 Net Income (Loss) $ 51 $ 91 $ — $ (91 ) $ 51 Other Comprehensive Income — — — — — Comprehensive Income (Loss) $ 51 $ 91 $ — $ (91 ) $ 51 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Six months ended June 30, 2019 Operating Revenues: Gas sales $ — $ 705 $ — $ — $ 705 Oil sales — 86 — — 86 NGL sales — 139 — — 139 Marketing — 725 — — 725 Other — 2 — — 2 — 1,657 — — 1,657 Operating Costs and Expenses: Marketing purchases — 734 — — 734 Operating expenses — 334 — — 334 General and administrative expenses — 77 — — 77 Loss on sale of operating assets — 3 — — 3 Restructuring charges — 5 — — 5 Depreciation, depletion and amortization — 233 — — 233 Taxes, other than income taxes — 36 — — 36 — 1,422 — — 1,422 Operating Income — 235 — — 235 Interest Expense, Net 29 — — — 29 Gain on Derivatives — 120 — — 120 Other Loss, Net — (5 ) — — (5 ) Equity in Earnings of Subsidiaries 761 — — (761 ) — Income (Loss) Before Income Taxes 732 350 — (761 ) 321 Benefit from Income Taxes — (411 ) — — (411 ) Net Income (Loss) $ 732 $ 761 $ — $ (761 ) $ 732 Net Income (Loss) $ 732 $ 761 $ — $ (761 ) $ 732 Other Comprehensive Income 4 — — — 4 Comprehensive Income (Loss) $ 736 $ 761 $ — $ (761 ) $ 736 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Six months ended June 30, 2018 Operating Revenues: Gas sales $ — $ 947 $ — $ — $ 947 Oil sales — 79 — — 79 NGL sales — 140 — — 140 Marketing — 518 — — 518 Gas gathering — 48 — — 48 Other — 4 — — 4 — 1,736 — — 1,736 Operating Costs and Expenses: Marketing purchases — 520 — — 520 Operating expenses — 382 — — 382 General and administrative expenses — 114 — — 114 Restructuring charges — 18 — — 18 Depreciation, depletion and amortization — 285 — — 285 Taxes, other than income taxes — 38 — — 38 — 1,357 — — 1,357 Operating Income — 379 — — 379 Interest Expense, Net 71 — — — 71 Loss on Derivatives — (43 ) — — (43 ) Loss on Early Extinguishment of Debt (8 ) — — — (8 ) Other Income, Net — 2 — — 2 Equity in Earnings of Subsidiaries 338 — — (338 ) — Income (Loss) Before Income Taxes 259 338 — (338 ) 259 Provision for Income Taxes — — — — — Net Income (Loss) $ 259 $ 338 $ — $ (338 ) $ 259 Participating securities - mandatory convertible preferred stock 2 — — — 2 Net Income (Loss) Attributable to Common Stock $ 257 $ 338 $ — $ (338 ) $ 257 Net Income (Loss) $ 259 $ 338 $ — $ (338 ) $ 259 Other Comprehensive Income — — — — — Comprehensive Income (Loss) $ 259 $ 338 $ — $ (338 ) $ 259 CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated June 30, 2019 ASSETS Cash and cash equivalents $ 155 $ — $ — $ — $ 155 Accounts receivable, net — 358 — — 358 Other current assets 5 246 — — 251 Total current assets 160 604 — — 764 Intercompany receivables 7,894 — — (7,894 ) — Natural gas and oil properties, using the full cost method — 24,769 54 — 24,823 Other 196 330 29 — 555 Less: Accumulated depreciation, depletion and amortization (162 ) (20,059 ) (58 ) — (20,279 ) Total property and equipment, net 34 5,040 25 — 5,099 Investments in subsidiaries (equity method) — 23 — (23 ) — Other long-term assets 45 637 — — 682 TOTAL ASSETS $ 8,133 $ 6,304 $ 25 $ (7,917 ) $ 6,545 LIABILITIES AND EQUITY Accounts payable $ 72 $ 513 $ — $ — $ 585 Other current liabilities 193 134 — — 327 Total current liabilities 265 647 — — 912 Intercompany payables — 7,892 2 (7,894 ) — Long-term debt 2,267 — — — 2,267 Pension and other postretirement liabilities 39 — — — 39 Other long-term liabilities 39 206 — — 245 Negative carrying amount of subsidiaries, net 2,441 — — (2,441 ) — Total long-term liabilities 4,786 206 — (2,441 ) 2,551 Commitments and contingencies Total equity (accumulated deficit) 3,082 (2,441 ) 23 2,418 3,082 TOTAL LIABILITIES AND EQUITY $ 8,133 $ 6,304 $ 25 $ (7,917 ) $ 6,545 CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated December 31, 2018 ASSETS Cash and cash equivalents $ 201 $ — $ — $ — $ 201 Accounts receivable, net 4 577 — — 581 Other current assets 8 166 — — 174 Total current assets 213 743 — — 956 Intercompany receivables 7,932 — — (7,932 ) — Natural gas and oil properties, using the full cost method — 24,128 52 — 24,180 Other 197 301 27 — 525 Less: Accumulated depreciation, depletion and amortization (154 ) (19,840 ) (55 ) — (20,049 ) Total property and equipment, net 43 4,589 24 — 4,656 Investments in subsidiaries (equity method) — 24 — (24 ) — Other long-term assets 19 166 — — 185 TOTAL ASSETS $ 8,207 $ 5,522 $ 24 $ (7,956 ) $ 5,797 LIABILITIES AND EQUITY Accounts payable $ 113 $ 496 $ — $ — $ 609 Other current liabilities 115 122 — — 237 Total current liabilities 228 618 — — 846 Intercompany payables — 7,932 — (7,932 ) — Long-term debt 2,318 — — — 2,318 Pension and other postretirement liabilities 46 — — — 46 Other long-term liabilities 54 171 — — 225 Negative carrying amount of subsidiaries, net 3,199 — — (3,199 ) — Total long-term liabilities 5,617 171 — (3,199 ) 2,589 Commitments and contingencies Total equity (accumulated deficit) 2,362 (3,199 ) 24 3,175 2,362 TOTAL LIABILITIES AND EQUITY $ 8,207 $ 5,522 $ 24 $ (7,956 ) $ 5,797 CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Six months ended June 30, 2019 Net cash provided by (used in) operating activities $ 1,124 $ 179 $ — $ (760 ) $ 543 Investing activities: Capital investments (1 ) (584 ) (1 ) — (586 ) Proceeds from sale — 26 — — 26 Net cash used in investing activities (1 ) (558 ) (1 ) — (560 ) Financing activities: Intercompany activities (1,140 ) 379 1 760 — Change in bank drafts outstanding (7 ) — — — (7 ) Purchase of treasury stock (21 ) — — — (21 ) Cash paid for tax withholding (1 ) — — — (1 ) Net cash provided by (used in) financing activities (1,169 ) 379 1 760 (29 ) Decrease in cash and cash equivalents (46 ) — — — (46 ) Cash and cash equivalents at beginning of year 201 — — — 201 Cash and cash equivalents at end of period $ 155 $ — $ — $ — $ 155  Six months ended June 30, 2018 Net cash provided by (used in) operating activities $ 276 $ 725 $ — $ (337 ) $ 664 Investing activities: Capital investments (6 ) (678 ) — — (684 ) Other — 9 — — 9 Net cash used in investing activities (6 ) (669 ) — — (675 ) Financing activities: Intercompany activities (287 ) (50 ) — 337 — Payments on long-term debt (1,191 ) — — — (1,191 ) Payments on revolving credit facility (645 ) — — — (645 ) Borrowings under revolving credit facility 1,005 — — — 1,005 Preferred stock dividend (27 ) — — — (27 ) Other (10 ) — — — (10 ) Net cash provided by (used in) financing activities (1,155 ) (50 ) — 337 (868 ) Increase (decrease) in cash and cash equivalents (885 ) 6 — — (879 ) Cash and cash equivalents at beginning of year 914 2 — — 916 Cash and cash equivalents at end of period $ 29 $ 8 $ — $ — $ 37

New Accounting Pronouncements (

New Accounting Pronouncements (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
New Accounting Standards Implemented/New Accounting Standards Not Yet Implemented	New Accounting Standards Implemented 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. The codification was amended through additional ASUs. For public entities, Update 2016-02 became effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company adopted ASC 842 with an effective date of January 1, 2019 using the modified retrospective approach for all leases that existed at the date of initial application. The Company elected to apply the transition as of the beginning of the period of adoption. For leases that existed at the period of adoption on January 1, 2019, the incremental borrowing rate as of the application date was used to calculate the present value of remaining lease payments. Upon adoption of ASC 842, the Company recognized a discounted right-of-use asset and corresponding lease liability with opening balances of approximately $105 million as of January 1, 2019 . The adoption of the standard did not materially change the Company’s consolidated statement of operations or its consolidated statement of cash flows. Please refer to Note 4 – “Leases” for full disclosure. New Accounting Standards Not Yet Implemented In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“Update 2016-13”). Update 2016-13 replaces the incurred loss model with an expected loss model, which is referred to as the current expected credit loss (“CECL”) model. The CECL model is applicable to the measurement of credit losses on financial assets measured at amortized cost, including but not limited to trade receivables. The Company is still performing its evaluation of Update 2016-13, but does not believe it will have a material impact on its consolidated financial statements at this time.

Restructuring Charges (Tables)

Restructuring Charges (Tables)	6 Months Ended
	Jun. 30, 2019
Restructuring and Related Activities [Abstract]
Summary of Restructuring Charges	The following table presents a summary of the restructuring charges included in Operating Income for the three and six months ended June 30, 2019 and 2018: For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Severance (including payroll taxes) $ 1 $ 17 $ 3 $ 17 Office consolidation 1 — 2 — Professional fees — 1 — 1 Total restructuring charges (1) $ 2 $ 18 $ 5 $ 18 (1) Total restructuring charges were $2 million and $ 5 million for the Company’s E&P segment for the three and six months ended June 30, 2019 , respectively, and $16 million and $2 million for the Company’s E&P and Midstream segments, respectively, for the three and six months ended June 30, 2018. The following table presents a reconciliation of the liability associated with the Company’s restructuring activities at June 30, 2019 , which is reflected in accounts payable on the consolidated balance sheet: (in millions) June 30, 2019 Liability at December 31, 2018 $ 5 Additions 5 Distributions (10 ) Liability at June 30, 2019 $ —

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lease costs	The components of lease costs are shown below: For the six months ended (in millions) Operating lease cost $ 22 Short-term lease cost 31 Variable lease cost — Total lease cost $ 53 As of June 30, 2019 , the Company has operating leases of $4 million , related primarily to compressor leases, that have been executed but not yet commenced. These operating leases are planned to commence during 2019 with lease terms expiring through 2022. The Company’s existing operating leases do not contain any material restrictive covenants. Supplemental cash flow information related to leases is set forth below: For the six months ended (in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 22 Right-of use assets obtained in exchange for new operating liabilities: Operating leases $ 6
Supplemental balance sheet information	Supplemental balance sheet information related to leases is as follows: Right-of-use asset balance: (in millions) June 30, 2019 Operating leases $ 103 Lease liability balance: (in millions) Short-term operating leases $ 47 Long-term operating leases 56 Total operating leases $ 103 Weighted average remaining lease term: (years) Operating leases 3.8 Weighted average discount rate: Operating leases 6.28 %
Lease maturity schedule	Maturity analysis of operating lease liabilities: (in millions) June 30, 2019 2019 $ 22 2020 42 2021 19 2022 10 2023 8 2024 5 Thereafter 9 Total undiscounted lease liability 115 Imputed interest (12 ) Total discounted lease liability $ 103 (in millions) December 31, 2018 2019 $ 38 2020 28 2021 14 2022 6 2023 5 Thereafter 4 Total minimum payments required $ 95

Revenue Recognition (Tables)

Revenue Recognition (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue by Segment	The Company presents a disaggregation of E&P revenues by product on the consolidated statements of operations net of intersegment revenues. The following table reconciles operating revenues as presented on the consolidated statements of operations to the operating revenues by segment: (in millions) E&P Midstream Intersegment Revenues Total Three months ended June 30, 2019 Gas sales $ 267 $ — $ 8 $ 275 Oil sales 46 — 1 47 NGL sales 58 — — 58 Marketing — 626 (339 ) 287 Total $ 371 $ 626 $ (330 ) $ 667 Three months ended June 30, 2018 Gas sales $ 400 $ — $ 7 $ 407 Oil sales 44 — — 44 NGL sales 75 — — 75 Marketing — 728 (463 ) 265 Gas gathering (1) — 69 (45 ) 24 Other (2) 1 — — 1 Total $ 520 $ 797 $ (501 ) $ 816 (in millions) E&P Midstream Intersegment Total Six months ended June 30, 2019 Gas sales $ 688 $ — $ 17 $ 705 Oil sales 85 — 1 86 NGL sales 139 — — 139 Marketing — 1,566 (841 ) 725 Other (2) 1 1 — 2 Total $ 913 $ 1,567 $ (823 ) $ 1,657 Six months ended June 30, 2018 Gas sales $ 935 $ — $ 12 $ 947 Oil sales 78 — 1 79 NGL sales 140 — — 140 Marketing — 1,557 (1,039 ) 518 Gas gathering (1) — 136 (88 ) 48 Other (2) 4 — — 4 Total $ 1,157 $ 1,693 $ (1,114 ) $ 1,736 (1) The Company’s gas gathering assets were divested in December 2018 as part of the Fayetteville Shale sale.
Disaggregation of Revenue on Geographic Basis	For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Northeast Appalachia $ 217 $ 213 $ 565 $ 540 Southwest Appalachia 153 166 346 322 Fayetteville Shale — 139 — 291 Other 1 2 2 4 Total $ 371 $ 520 $ 913 $ 1,157
Reconciliation of Accounts Receivable	The following table reconciles the Company’s receivables from contracts with customers to consolidated accounts receivable as presented on the consolidated balance sheet: (in millions) June 30, 2019 December 31, 2018 Receivables from contracts with customers $ 238 $ 494 Other accounts receivable 120 87 Total accounts receivable $ 358 $ 581

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	6 Months Ended
	Jun. 30, 2019
Cash and Cash Equivalents [Abstract]
Summary of Cash and Cash Equivalents	The following table presents a summary of cash and cash equivalents as of June 30, 2019 and December 31, 2018 : (in millions) June 30, 2019 December 31, 2018 Cash $ 71 $ 32 Marketable securities (1) 69 169 Other cash equivalents (2) 15 — Total $ 155 $ 201 (1) Consists of government stable value money market funds. (2) Consists of time deposits.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share	The following table presents the computation of earnings per share for the three and six months ended June 30, 2019 and 2018 :  For the three months ended June 30, For the six months ended June 30, (in millions, except share/per share amounts) 2019 2018 2019 2018 Net income $ 138 $ 51 $ 732 $ 259 Participating securities - mandatory convertible preferred stock — — — 2 Net income attributable to common stock $ 138 $ 51 $ 732 $ 257  Number of common shares: Weighted average outstanding 539,005,941 581,159,200 539,362,984 576,255,744 Issued upon assumed exercise of outstanding stock options — — — — Effect of issuance of non-vested restricted common stock 311,732 480,580 481,948 683,562 Effect of issuance of non-vested performance units 629,380 1,238,326 779,810 1,283,434 Weighted average and potential dilutive outstanding 539,947,053 582,878,106 540,624,742 578,222,740  Earnings per common share Basic $ 0.26 $ 0.09 $ 1.36 $ 0.45 Diluted $ 0.26 $ 0.09 $ 1.35 $ 0.44
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table presents the common stock shares equivalent excluded from the calculation of diluted earnings per share for the three and six months ended June 30, 2019 and 2018 , as they would have had an antidilutive effect:  For the three months ended June 30, For the six months ended June 30,  2019 2018 2019 2018 Unexercised stock options 5,114,763 — 5,121,663 — Unvested share-based payment 1,773,074 4,335,715 1,822,346 5,152,847 Performance units 241,896 875,800 250,998 986,585 Mandatory convertible preferred stock — — — 4,972,284 Total 7,129,733 5,211,515 7,195,007 11,111,716

Derivatives and Risk Manageme_2

Derivatives and Risk Management (Tables)	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments Notional Amount, Weighted Average Contract Prices and Fair Value	The following tables provide 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 tables present the notional amount, the weighted average contract prices and the fair value by expected maturity dates as of June 30, 2019 : Financial Protection on Production  Weighted Average Price per MMBtu  Volume (Bcf) Swaps Sold Puts Purchased Puts Sold Calls Basis Differential Fair Value at June 30, 2019 (in millions) Natural Gas 2019 Fixed price swaps 131 $ 2.92 $ — $ — $ — $ — $ 75 Two-way costless collars 25 — — 2.78 2.92 — 13 Three-way costless collars 67 — 2.47 2.88 3.22 — 22 Total 223 $ 110 2020 Fixed price swaps 24 $ 2.88 $ — $ — $ — $ — $ 8 Three-way costless collars 148 — 2.36 2.67 2.97 — 10 Total 172 $ 18 2021 Three-way costless collars 37 $ — $ 2.35 $ 2.60 $ 2.93 $ — $ (1 )  Basis Swaps 2019 80 $ — $ — $ — $ — $ (0.45 ) $ (6 ) 2020 132 — — — — (0.34 ) (10 ) 2021 28 — — — — (0.51 ) (1 ) Total 240 $ (17 )  Volume (MBbls) Weighted Average Strike Price per Bbl Fair Value at June 30, 2019 (in millions) Swaps Sold Puts Purchased Puts Sold Calls Oil 2019 Fixed price swaps (1) 1,003 $ 60.89 $ — $ — $ — $ 4 Two-way costless collars 764 — — 61.45 67.16 4 Three-way costless collars 276 — 45.00 55.00 63.67 — Total 2,043 $ 8 2020 Fixed price swaps 1,556 $ 60.18 $ — $ — $ — $ 7 Two-way costless collars 366 — — 60.00 69.80 3 Three-way costless collars 641 — 45.00 55.00 63.36 1 Total 2,563 $ 11 Propane 2019 Fixed price swaps 1,955 $ 30.18 $ — $ — $ — $ 14 Two-way costless collars 276 — — 25.62 28.77 1 Total 2,231 $ 15 2020 Fixed price swaps 2,196 $ 26.97 $ — $ — $ — $ 6 Two-way costless collars 366 — — 25.20 $ 29.40 1 Total 2,562 $ 7  Ethane 2019 Fixed price swaps 1,858 $ 13.90 $ — $ — $ — $ 10 2020 Fixed price swaps 732 $ 13.49 $ — $ — $ — $ 2 (1) Includes 138 MBbls of purchased fixed price oil swaps hedged at $69.10 per barrel with a fair value of ($1) million and 1,141 MBbls of sold fixed price oil swaps hedged at $61.88 with a fair value of $5 million . Other Derivative Contracts  Volume (Bcf) Weighted Average Strike Price per MMBtu Fair Value at June 30, 2019 (in millions) Purchased Call Options – Natural Gas 2019 17 $ 3.50 $ — 2020 68 3.63 2 2021 57 3.52 2 Total 142 $ 4  Sold Call Options – Natural Gas 2019 26 $ 3.50 $ — 2020 137 3.39 (8 ) 2021 114 3.33 (8 ) Total 277 $ (16 ) ໿  Volume (Bcf) Weighted Average Strike Price per MMBtu Basis Differential per MMBtu Fair Value at June 30, 2019 ($ in millions) Storage (1) 2019 Purchased fixed price swaps 1 $ 2.87 $ — $ (1 ) Purchased basis swaps 1 — (0.53 ) — Total 2 $ (1 ) 2020 Fixed price swap 1 $ 3.14 $ — $ — (1) The Company has entered into certain derivatives to protect the value of volumes of natural gas injected into a storage facility that will be withdrawn at a later date.
Balance Sheet Classification of Derivative Financial Instruments	The balance sheet classification of the assets and liabilities related to derivative financial instruments (none of which are designated for hedge accounting treatment) is summarized below as of June 30, 2019 and December 31, 2018 : Derivative Assets  Fair Value (in millions) Balance Sheet Classification June 30, 2019 December 31, 2018 Derivatives not designated as hedging instruments: Fixed price swaps – natural gas Derivative assets $ 79 $ 32 Fixed price swaps – oil Derivative assets 7 13 Fixed price swaps – propane Derivative assets 18 11 Fixed price swaps – ethane Derivative assets 11 7 Two-way costless collars – natural gas Derivative assets 13 11 Two-way costless collars – oil Derivative assets 6 6 Two-way costless collars – propane Derivative assets 2 — Three-way costless collars – natural gas Derivative assets 65 41 Three-way costless collars – oil Derivative assets 2 — Basis swaps – natural gas Derivative assets 5 8 Purchased call options – natural gas Derivative assets 1 (1) — Interest rate swaps Derivative assets — 1 Fixed price swaps – natural gas Other long-term assets 4 6 Fixed price swaps – oil Other long-term assets 4 6 Fixed price swaps – propane Other long-term assets 2 — Fixed price swaps – ethane Other long-term assets 1 1 Two-way costless collars – oil Other long-term assets 2 5 Three-way costless collars – natural gas Other long-term assets 31 34 Three-way costless collars – oil Other long-term assets 2 — Basis swaps – natural gas Other long-term assets 2 3 Purchased call options – natural gas Other long-term assets 4 6 Total derivative assets $ 261 $ 191 Derivative Liabilities  Fair Value (in millions) Balance Sheet Classification June 30, 2019 December 31, 2018 Derivatives not designated as hedging instruments: Purchased fixed price swap – oil Derivative liabilities $ 1 $ 6 Fixed price swaps – natural gas Derivative liabilities — 9 Fixed price swaps – ethane Derivative liabilities — 3 Two-way costless collars – natural gas Derivative liabilities — 7 Two-way costless collars – oil Derivative liabilities 1 — Three-way costless collars – natural gas Derivative liabilities 37 33 Three-way costless collars – oil Derivative liabilities 2 — Basis swaps – natural gas Derivative liabilities 19 18 Sold call options – natural gas Derivative liabilities 5 3 Storage – fixed price swap Derivative liabilities 1 — Interest rate swaps Derivative liabilities 1 — Fixed price swaps – natural gas Other long-term liabilities — 1 Two-way costless collars – oil Other long-term liabilities — 1 Three-way costless collars – natural gas Other long-term liabilities 28 35 Three-way costless collars – oil Other long-term liabilities 1 — Basis swap – natural gas Other long-term liabilities 5 4 Sold call options – natural gas Other long-term liabilities 11 19 Total derivative liabilities $ 112 $ 139 (1) Includes $1 million in premiums paid related to certain natural gas purchased call options recognized as a component of derivative assets within current assets on the consolidated balance sheet at June 30, 2019 . As certain natural gas purchased call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the consolidated statements of operations.
Summary of Before Tax Effect of Fair Value Hedges not Designated for Hedge Accounting	The following tables summarize the before-tax effect of the Company’s derivative instruments on the consolidated statements of operations for the three and six months ended June 30, 2019 and 2018 : Unsettled Gain (Loss) on Derivatives Recognized in Earnings Derivative Instrument Consolidated Statement of Operations Classification of Gain (Loss) on Derivatives, Unsettled For the three months ended June 30, For the six months ended June 30, 2019 2018 2019 2018  (in millions) Purchased fixed price swaps – oil Gain (Loss) on Derivatives $ 1 $ — $ 5 $ — Fixed price swaps – natural gas Gain (Loss) on Derivatives 57 (26 ) 55 (29 ) Fixed price swaps – oil Gain (Loss) on Derivatives 5 — (8 ) — Fixed price swaps – propane Gain (Loss) on Derivatives 13 (12 ) 9 (9 ) Fixed price swaps – ethane Gain (Loss) on Derivatives — (2 ) 7 (2 ) Two-way costless collars – natural gas Gain (Loss) on Derivatives 10 (1 ) 9 2 Two-way costless collars – oil Gain (Loss) on Derivatives 4 — (3 ) — Two-way costless collars – propane Gain (Loss) on Derivatives 2 — 2 — Three-way costless collars – natural gas Gain (Loss) on Derivatives 22 (24 ) 24 (29 ) Three-way costless collars – oil Gain (Loss) on Derivatives 1 — 1 — Basis swaps – natural gas Gain (Loss) on Derivatives 4 (4 ) (6 ) 16 Purchased call options – natural gas Gain (Loss) on Derivatives (2 ) (12 ) (2 ) 4 Sold call options – natural gas Gain (Loss) on Derivatives 4 31 6 (3 ) Sold call options – oil Gain (Loss) on Derivatives — (6 ) — (6 ) Storage – fixed price swap Gain (Loss) on Derivatives (1 ) — (1 ) — Interest rate swaps Gain (Loss) on Derivatives (2 ) — (2 ) 2 Total gain (loss) on unsettled derivatives $ 118 $ (56 ) $ 96 $ (54 ) Settled Gain (Loss) on Derivatives Recognized in Earnings (1) Derivative Instrument Consolidated Statement of Operations Classification of Gain (Loss) on Derivatives, Settled For the three months ended June 30, For the six months ended June 30, 2019 2018 2019 2018 (in millions) Purchased fixed price swaps – oil Gain (Loss) on Derivatives $ (1 ) $ — $ (2 ) $ — Sold fixed price swaps – natural gas Gain (Loss) on Derivatives 14 13 8 13 Sold fixed price swaps – oil Gain (Loss) on Derivatives 2 — 4 — Sold fixed price swaps – propane Gain (Loss) on Derivatives 7 (1 ) 9 (1 ) Sold fixed price swaps – ethane Gain (Loss) on Derivatives 5 — 6 — Two-way costless collars – natural gas Gain (Loss) on Derivatives 3 — 2 4 Two-way costless collars – oil Gain (Loss) on Derivatives 1 — 2 — Three-way costless collars – natural gas Gain (Loss) on Derivatives 8 12 4 19 Sold basis swaps – natural gas Gain (Loss) on Derivatives (4 ) (3 ) (8 ) (24 ) Purchased call options – natural gas Gain (Loss) on Derivatives — — — 2 (2) Sold call options – natural gas Gain (Loss) on Derivatives (1 ) — (1 ) (1 ) Sold call options – oil Gain (Loss) on Derivatives — (1 ) — (1 ) Total gain on settled derivatives $ 34 $ 20 $ 24 $ 11  Total gain (loss) on derivatives $ 152 $ (36 ) $ 120 $ (43 ) (1) The Company calculates gain (loss) on derivatives, settled, as the summation of gains and losses on positions that settled within the period. (2) Includes $1 million amortization of premiums paid related to certain natural gas call options for the six months ended June 30, 2018 , which is included in gain (loss) on derivatives on the consolidated statements of operations.

Reclassifications from Accumu_2

Reclassifications from Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Components of Accumulated Other Comprehensive Income (Loss)	The following tables detail the components of accumulated other comprehensive income and the related tax effects for the six months ended June 30, 2019 : (in millions) Pension and Other Postretirement Foreign Currency Total Beginning balance December 31, 2018 $ (22 ) $ (14 ) $ (36 ) Other comprehensive income before reclassifications — — — Amounts reclassified from other comprehensive income (1) 4 — 4 Net current-period other comprehensive income 4 — 4 Ending balance June 30, 2019 $ (18 ) $ (14 ) $ (32 ) (1) See separate table below for details about these reclassifications.
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	Details about Accumulated Other Affected Line Item in the Amount Reclassified from Accumulated Other Comprehensive Income For the six months ended (in millions) Pension and other postretirement: Amortization of prior service cost and net loss (1) Other Income, Net $ 5 Provision for income taxes 1 Net income $ 4 Total reclassifications for the period Net income $ 4 ໿ (1) See Note 15 for additional details regarding the Company’s pension and other postretirement benefit plans.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Carrying Amount and Estimated Fair Values of Financial Instruments	The carrying amounts and estimated fair values of the Company’s financial instruments as of June 30, 2019 and December 31, 2018 were as follows:  June 30, 2019 December 31, 2018 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Cash and cash equivalents $ 155 $ 155 $ 201 $ 201 2018 revolving credit facility due April 2023 — — — — Senior notes (1) 2,342 2,220 2,342 2,190 Derivative instruments, net 149 (2) 149 (2) 52 52 (1) Excludes unamortized debt issuance costs and debt discounts. (2) Includes $1 million in premiums paid related to certain natural gas purchased call options recognized as a component of derivative assets within current assets on the consolidated balance sheet.
Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are summarized below:  June 30, 2019  Fair Value Measurements Using: (in millions) Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value Assets Fixed price swap – natural gas $ — $ 83 $ — $ 83 Fixed price swap – oil — 11 — 11 Fixed price swap – propane — 20 — 20 Fixed price swap – ethane — 12 — 12 Two-way costless collar – natural gas — 13 — 13 Two-way costless collar – oil — 8 — 8 Two-way costless collar – propane — 2 — 2 Three-way costless collar – natural gas — 96 — 96 Three-way costless collar – oil — 4 — 4 Basis swap – natural gas — 7 — 7 Purchased call option – natural gas (1) — 5 — 5 Liabilities Purchased fixed price swap – oil — (1 ) — (1 ) Two-way costless collar – oil — (1 ) — (1 ) Three-way costless collar – natural gas — (65 ) — (65 ) Three-way costless collar – oil — (3 ) — (3 ) Basis swap – natural gas — (24 ) — (24 ) Sold call option – natural gas — (16 ) — (16 ) Storage – fixed price swap — (1 ) — (1 ) Interest rate swap — (1 ) — (1 ) Total $ — $ 149 $ — $ 149 (1) Includes $1 million in premiums paid related to certain natural gas purchased call options recognized as a component of derivative assets within current assets on the consolidated balance sheet at June 30, 2019 . As certain natural gas purchased call options settle, the premium will be amortized and recognized as a component of gain (loss) on derivatives on the consolidated statements of operations.  December 31, 2018  Fair Value Measurements Using: (in millions) Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets (Liabilities) at Fair Value Assets Fixed price swap – natural gas $ — $ 38 $ — $ 38 Fixed price swap – oil — 19 — 19 Fixed price swap – propane — 11 — 11 Fixed price swap – ethane — 8 — 8 Two-way costless collar – natural gas — 11 — 11 Two-way costless collar – oil — 11 — 11 Three-way costless collar – natural gas — 75 — 75 Basis swap – natural gas — 11 — 11 Purchased call option – natural gas — 6 — 6 Interest rate swap — 1 — 1 Liabilities Purchased fixed price swap – oil — (6 ) — (6 ) Fixed price swap – natural gas — (10 ) — (10 ) Fixed price swap – ethane — (3 ) — (3 ) Two-way costless collar – natural gas — (7 ) — (7 ) Two-way costless collar – oil — (1 ) — (1 ) Three-way costless collar – natural gas — (68 ) — (68 ) Basis swap – natural gas — (22 ) — (22 ) Sold call option – natural gas — (22 ) — (22 ) Total $ — $ 52 $ — $ 52
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)	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 unobservable inputs (Level 3) for the three and six months ended June 30, 2019 and 2018 . The fair values of Level 3 derivative instruments were estimated using proprietary valuation models that utilized both market observable and unobservable parameters. Level 3 instruments presented in the table consisted of net derivatives valued using pricing models incorporating assumptions that, in the Company’s judgment, reflected reasonable assumptions a marketplace participant would have used as of June 30, 2018 . Commodity derivatives previously presented as Level 3 were transferred to Level 2 in the second quarter of 2018 as the Company moved from using proprietary volatility inputs and forward curves to more widely available published information, increasing market observability. ໿  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Balance at beginning of period $ — $ 22 $ — $ 22 Total gains (losses): Included in earnings — (8 ) — (17 ) Settlements — (8 ) — 1 (1) Transfers into/out of Level 3 — (6 ) (2) — (6 ) (2) Balance at end of period $ — $ — $ — $ — Change in gains (losses) included in earnings relating to derivatives still held as of June 30 $ — $ — $ — $ — (1) Includes $1 million amortization of premiums paid related to certain natural gas call options for the six months ended June 30, 2018 . (2) Commodity derivatives previously presented as Level 3 were transferred to Level 2 in the second quarter of 2018 as the Company moved from using proprietary volatility inputs and forward curves to more widely available published information, increasing market observability.

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Components of Debt	The components of debt as of June 30, 2019 and December 31, 2018 consisted of the following: June 30, 2019 (in millions) Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total Current portion of long-term debt: 4.05% Senior Notes due January 2020 (1) $ 52 $ — $ — $ 52 Total current portion of long-term debt $ 52 $ — $ — $ 52 Long-term debt: Variable rate (3.880% at June 30, 2019) 2018 revolving credit facility, due April 2023 $ — $ — (2) $ — $ — 4.10% Senior Notes due March 2022 213 (1 ) — 212 4.95% Senior Notes due January 2025 (1) 927 (7 ) (1 ) 919 7.50 % Senior Notes due April 2026 650 (8 ) — 642 7.75 % Senior Notes due October 2027 500 (6 ) — 494 Total long-term debt $ 2,290 $ (22 ) $ (1 ) $ 2,267 Total debt $ 2,342 $ (22 ) $ (1 ) $ 2,319 December 31, 2018 (in millions) Debt Instrument Unamortized Issuance Expense Unamortized Debt Discount Total Long-term debt: Variable rate (3.920% at December 31, 2018) 2018 term loan facility, due April 2023 $ — $ — (2) $ — $ — 4.05% Senior Notes due January 2020 (1) 52 — — 52 4.10% Senior Notes due March 2022 213 (1 ) — 212 4.95% Senior Notes due January 2025 (1) 927 (7 ) (1 ) 919 7.50% Senior Notes due April 2026 650 (8 ) — 642 7.75% Senior Notes due October 2027 500 (7 ) — 493 Total long-term debt $ 2,342 $ (23 ) $ (1 ) $ 2,318 (1) 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 5.80% for the 2020 Notes and 6.70% for the 2025 Notes. In April and May 2018, S&P and Moody’s upgraded certain senior notes. As a result of these upgrades, interest rates decreased to 5.30% for the 2020 Notes and 6.20% for the 2025 Notes effective July 2018 . The first coupon payment to the bondholders at the lower interest rate was paid in January 2019 . (2) At June 30, 2019 and December 31, 2018 , unamortized issuance expense of $10 million and $11 million , respectively, associated with the 2018 revolving credit facility is classified as other long-term assets on the consolidated balance sheets.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Obligation under Transportation Agreements	As of June 30, 2019 , future payments under non-cancelable firm transportation and gathering agreements were as follows:  Payments Due by Period (in millions) Total Less than 1 Year 1 to 3 Years 3 to 5 Years 5 to 8 Years More than 8 Years Infrastructure currently in service $ 7,501 $ 702 $ 1,304 $ 1,097 $ 1,511 $ 2,887 Pending regulatory approval and/or construction (1) 966 9 78 121 196 562 Total transportation charges $ 8,467 $ 711 $ 1,382 $ 1,218 $ 1,707 $ 3,449 (1) Based on estimated in-service dates as of June 30, 2019 .

Pension Plan and Other Postre_2

Pension Plan and Other Postretirement Benefits (Tables)	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefit Costs	The Company maintains defined pension and other postretirement benefit plans, which cover substantially all of the Company’s employees. Net periodic pension costs include the following components for the three and six months ended June 30, 2019 and 2018 :  Pension Benefits  Consolidated Statements of Operations Classification of Net Periodic Benefit Cost For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Service cost General and administrative expenses $ 2 $ 3 $ 4 $ 6 Interest cost Other Income (Loss), Net 1 1 2 3 Expected return on plan assets Other Income (Loss), Net (1 ) (2 ) (3 ) (4 ) Amortization of prior service cost Other Income (Loss), Net — — — — Amortization of net loss Other Income (Loss), Net — — 1 — Settlement loss Other Income (Loss), Net 4 — 4 — Net periodic benefit cost $ 6 $ 2 $ 8 $ 5

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Share-based Compensation [Abstract]
Schedule of Stock-Based Compensation Costs	The Company recognized the following amounts in total employee stock-based compensation costs for the three and six months ended June 30, 2019 and 2018 :  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Stock-based compensation cost – expensed $ 4 $ 8 $ 11 $ 13 Stock-based compensation cost – capitalized 2 4 6 7
Schedule of Equity-Classified Stock-Based Compensation Costs	The Company recognized the following amounts in employee equity-classified stock-based compensation costs for the three and six months ended June 30, 2019 and 2018 :  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Equity-classified awards – expensed $ 2 $ 5 $ 4 $ 9 Equity-classified awards – capitalized 1 1 2 4
Summary of Equity-Classified Stock Option Activity	The following table summarizes equity-classified stock option activity for the six months ended June 30, 2019 and provides information for options outstanding and options exercisable as of June 30, 2019 :  Number of Options Weighted Average Exercise Price  (in thousands) Outstanding at December 31, 2018 5,178 $ 17.06 Granted — $ — Exercised — $ — Forfeited or expired (72 ) $ 18.58 Outstanding at June 30, 2019 5,106 $ 17.04 Exercisable at June 30, 2019 4,590 $ 18.12
Summary of Equity-Classified Restricted Stock Activity	The following table summarizes equity-classified restricted stock activity for the six months ended June 30, 2019 and provides information for unvested shares as of June 30, 2019 :  Number of Shares Weighted Average Fair Value  (in thousands) Unvested shares at December 31, 2018 2,717 $ 7.91 Granted 15 $ 4.12 Vested (990 ) $ 7.37 Forfeited (175 ) $ 8.37 Unvested shares at June 30, 2019 1,567 $ 8.17
Summary of Equity-Classified Performance Units Activity	The following table summarizes equity-classified performance unit activity for the six months ended June 30, 2019 and provides information for unvested units as of June 30, 2019 . The performance unit awards granted in 2017 include a market condition based exclusively on the fair value of the Total Shareholder Return (“TSR”), as calculated by a Monte Carlo model. The total fair value of the performance units is amortized to compensation expense on a straight line basis over the vesting period of the award. The grant date fair value is calculated using the closing price of the Company’s common stock at the grant date.  Number of Shares (1) Weighted Average Fair Value  (in thousands) Unvested units at December 31, 2018 598 $ 10.01 Granted — $ — Vested (371 ) $ 9.73 Forfeited (30 ) $ 10.47 Unvested units at June 30, 2019 197 $ 10.47 (1) The actual payout of shares may range from a minimum of zero shares to a maximum of two shares per unit contingent upon TSR. 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.
Schedule of Liability-Classified Stock-Based Compensation Costs	The Company recognized the following amounts in employee liability-classified stock-based compensation costs for the three and six months ended June 30, 2019 :  For the three months ended June 30, For the six months ended June 30, (in millions) 2019 2018 2019 2018 Liability-classified stock-based compensation cost – expensed $ 2 $ 3 $ 7 $ 4 Liability-classified stock-based compensation cost – capitalized 1 3 4 3
Summary of Liability-Classified Restricted Stock Unit Activity	As of June 30, 2019 , there was $38 million of total unrecognized compensation cost related to liability-classified restricted stock units that is expected to be recognized over a weighted-average period of 3.2 years . The amount of unrecognized compensation cost for liability-classified awards will fluctuate over time as they are marked to market.  Number of Units Weighted Average Fair Value  (in thousands) Unvested shares at December 31, 2018 8,202 $ 3.41 Granted 8,659 $ 4.34 Vested (2,617 ) $ 4.09 Forfeited (739 ) $ 3.13 Unvested units at June 30, 2019 13,505 $ 3.16
Summary of Liability-Classified Performance Unit Activity	 Number of Shares Weighted Average Fair Value  (in thousands) Unvested shares at December 31, 2018 2,803 $ 3.41 Granted 2,757 $ 4.34 Vested — $ — Forfeited (119 ) $ 4.65 Unvested units at June 30, 2019 5,441 $ 3.16

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Summary of Financial Information for Company's Reportable Segments	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 2018 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 operating income, interest expense, gain (loss) on derivatives and other income (loss). The “Other” column includes items not related to the Company’s reportable segments, including real estate and corporate items.  E&P Midstream Other Total Three months ended June 30, 2019 (in millions) Revenues from external customers $ 380 $ 287 $ — $ 667 Intersegment revenues (9 ) 339 — 330 Depreciation, depletion and amortization expense 118 3 — 121 Operating income (loss) 30 (1) (8 ) — 22 Interest expense (2) 15 — — 15 Gain on derivatives 152 — — 152 Other loss, net (5 ) — (1 ) (6 ) Provision for income taxes (2) 15 — — 15 Assets 5,945 (3) 277 323 (4) 6,545 Capital investments (5) 367 — 1 368  Three months ended June 30, 2018 Revenues from external customers $ 527 $ 289 $ — $ 816 Intersegment revenues (7 ) 508 — 501 Depreciation, depletion and amortization expense 126 16 — 142 Operating income (6) 97 (1) 27 (7) — 124 Interest expense (2) 32 — — 32 Loss on derivatives (36 ) — — (36 ) Loss on early extinguishment of debt — — (8 ) (8 ) Other income, net 3 — — 3 Assets 5,583 (3) 1,228 231 (4) 7,042 Capital investments (5) 396 5 2 403 E&P Midstream Other Total Six months ended June 30, 2019 (in millions) Revenues from external customers $ 931 $ 726 $ — $ 1,657 Intersegment revenues (18 ) 841 — 823 Depreciation, depletion and amortization expense 228 5 — 233 Operating income (loss) 240 (1) (5 ) — 235 Interest expense (2) 29 — — 29 Gain on derivatives 120 — — 120 Other loss, net (4 ) — (1 ) (5 ) Benefit from income taxes (2) (411 ) — — (411 ) Assets 5,945 (3) 277 323 (4) 6,545 Capital investments (5) 692 — 1 693 Six months ended June 30, 2018 Revenues from external customers $ 1,170 $ 566 $ — $ 1,736 Intersegment revenues (13 ) 1,127 — 1,114 Depreciation, depletion and amortization expense 243 42 (8) — 285 Operating income (6) 335 (1) 44 (7) — 379 Interest expense (2) 71 — — 71 Loss on derivatives (43 ) — — (43 ) Loss on early extinguishment of debt — — (8 ) (8 ) Other income (loss), net 3 (1 ) — 2 Assets 5,583 (3) 1,228 231 (4) 7,042 Capital investments (5) 730 9 2 741 (1) Operating income for the E&P segment includes $2 million and $16 million of restructuring charges for the three months ended June 30, 2019 and 2018 , respectively, and $5 million and $16 million of restructuring charges for the six months ended June 30, 2019 and 2018 , respectively. (2) Interest expense and provision (benefit) for income taxes by segment is an allocation of corporate amounts as they are incurred at the corporate level. (3) E&P assets includes office, technology, water infrastructure, drilling rigs and other ancillary equipment not directly related to natural gas and oil properties. This also includes deferred tax assets which are an allocation of corporate amounts as they are incurred at the corporate level. (4) Other assets represent corporate assets not allocated to segments and assets for non-reportable segments. At June 30, 2019 and 2018 , other assets included approximately $155 million and $37 million , respectively, in cash and cash equivalents, $68 million and $89 million , respectively, in income taxes receivable, $50 million and $83 million , respectively, in property, plant and equipment, $10 million and $12 million , respectively, in unamortized debt expense, $6 million and $8 million , respectively, in a non-qualified retirement plan and $3 million , respectively, in other assets for both periods presented. Additionally, the June 30, 2019 asset balance includes $29 million in right-of-use lease assets. (5) Capital investments include increases of $39 million and $19 million for the three months ended June 30, 2019 and 2018 , respectively, and increases of $105 million and $52 million for the six months ended June 30, 2019 and 2018 , respectively, relating to the change in accrued expenditures between years. (6) Includes the impact of Fayetteville Shale-related E&P and Midstream operations which were divested on December 3, 2018. (7) Operating income for the Midstream segment includes $2 million related to restructuring charges for the three and six months ended June 30, 2018 . (8) Includes a $10 million impairment related to certain non-core gathering assets.

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information (Tables)	6 Months Ended
	Jun. 30, 2019
Condensed Financial Information Disclosure [Abstract]
Condensed Consolidating Statements Of Operations	CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Three months ended June 30, 2019 Operating Revenues: Gas sales $ — $ 275 $ — $ — $ 275 Oil sales — 47 — — 47 NGL sales — 58 — — 58 Marketing — 287 — — 287 — 667 — — 667 Operating Costs and Expenses: Marketing purchases — 293 — — 293 Operating expenses — 169 — — 169 General and administrative expenses — 40 — — 40 Loss on sale of operating assets — 3 — — 3 Restructuring charges — 2 — — 2 Depreciation, depletion and amortization — 121 — — 121 Taxes, other than income taxes — 17 — — 17 — 645 — — 645 Operating Income — 22 — — 22 Interest Expense, Net 15 — — — 15 Gain on Derivatives — 152 — — 152 Other Loss, Net — (6 ) — — (6 ) Equity in Earnings of Subsidiaries 153 — — (153 ) — Income (Loss) Before Income Taxes 138 168 — (153 ) 153 Provision for Income Taxes — 15 — — 15 Net Income (Loss) $ 138 $ 153 $ — $ (153 ) $ 138 Net Income (Loss) $ 138 $ 153 $ — $ (153 ) $ 138 Other Comprehensive Income 4 — — — 4 Comprehensive Income (Loss) $ 142 $ 153 $ — $ (153 ) $ 142 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Three months ended June 30, 2018 Operating Revenues: Gas sales $ — $ 407 $ — $ — $ 407 Oil sales — 44 — — 44 NGL sales — 75 — — 75 Marketing — 265 — — 265 Gas gathering — 24 — — 24 Other — 1 — — 1 — 816 — — 816 Operating Costs and Expenses: Marketing purchases — 265 — — 265 Operating expenses — 193 — — 193 General and administrative expenses — 59 — — 59 Restructuring charges — 18 — — 18 Depreciation, depletion and amortization — 142 — — 142 Taxes, other than income taxes — 15 — — 15 — 692 — — 692 Operating Income — 124 — — 124 Interest Expense, Net 32 — — — 32 Loss on Derivatives — (36 ) — — (36 ) Loss on Early Extinguishment of Debt (8 ) — — — (8 ) Other Income, Net — 3 — — 3 Equity in Earnings of Subsidiaries 91 — — (91 ) — Income (Loss) Before Income Taxes 51 91 — (91 ) 51 Provision for Income Taxes — — — — — Net Income (Loss) $ 51 $ 91 $ — $ (91 ) $ 51 Net Income (Loss) $ 51 $ 91 $ — $ (91 ) $ 51 Other Comprehensive Income — — — — — Comprehensive Income (Loss) $ 51 $ 91 $ — $ (91 ) $ 51 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Six months ended June 30, 2019 Operating Revenues: Gas sales $ — $ 705 $ — $ — $ 705 Oil sales — 86 — — 86 NGL sales — 139 — — 139 Marketing — 725 — — 725 Other — 2 — — 2 — 1,657 — — 1,657 Operating Costs and Expenses: Marketing purchases — 734 — — 734 Operating expenses — 334 — — 334 General and administrative expenses — 77 — — 77 Loss on sale of operating assets — 3 — — 3 Restructuring charges — 5 — — 5 Depreciation, depletion and amortization — 233 — — 233 Taxes, other than income taxes — 36 — — 36 — 1,422 — — 1,422 Operating Income — 235 — — 235 Interest Expense, Net 29 — — — 29 Gain on Derivatives — 120 — — 120 Other Loss, Net — (5 ) — — (5 ) Equity in Earnings of Subsidiaries 761 — — (761 ) — Income (Loss) Before Income Taxes 732 350 — (761 ) 321 Benefit from Income Taxes — (411 ) — — (411 ) Net Income (Loss) $ 732 $ 761 $ — $ (761 ) $ 732 Net Income (Loss) $ 732 $ 761 $ — $ (761 ) $ 732 Other Comprehensive Income 4 — — — 4 Comprehensive Income (Loss) $ 736 $ 761 $ — $ (761 ) $ 736 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Six months ended June 30, 2018 Operating Revenues: Gas sales $ — $ 947 $ — $ — $ 947 Oil sales — 79 — — 79 NGL sales — 140 — — 140 Marketing — 518 — — 518 Gas gathering — 48 — — 48 Other — 4 — — 4 — 1,736 — — 1,736 Operating Costs and Expenses: Marketing purchases — 520 — — 520 Operating expenses — 382 — — 382 General and administrative expenses — 114 — — 114 Restructuring charges — 18 — — 18 Depreciation, depletion and amortization — 285 — — 285 Taxes, other than income taxes — 38 — — 38 — 1,357 — — 1,357 Operating Income — 379 — — 379 Interest Expense, Net 71 — — — 71 Loss on Derivatives — (43 ) — — (43 ) Loss on Early Extinguishment of Debt (8 ) — — — (8 ) Other Income, Net — 2 — — 2 Equity in Earnings of Subsidiaries 338 — — (338 ) — Income (Loss) Before Income Taxes 259 338 — (338 ) 259 Provision for Income Taxes — — — — — Net Income (Loss) $ 259 $ 338 $ — $ (338 ) $ 259 Participating securities - mandatory convertible preferred stock 2 — — — 2 Net Income (Loss) Attributable to Common Stock $ 257 $ 338 $ — $ (338 ) $ 257 Net Income (Loss) $ 259 $ 338 $ — $ (338 ) $ 259 Other Comprehensive Income — — — — — Comprehensive Income (Loss) $ 259 $ 338 $ — $ (338 ) $ 259
Condensed Consolidating Balance Sheets	CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated June 30, 2019 ASSETS Cash and cash equivalents $ 155 $ — $ — $ — $ 155 Accounts receivable, net — 358 — — 358 Other current assets 5 246 — — 251 Total current assets 160 604 — — 764 Intercompany receivables 7,894 — — (7,894 ) — Natural gas and oil properties, using the full cost method — 24,769 54 — 24,823 Other 196 330 29 — 555 Less: Accumulated depreciation, depletion and amortization (162 ) (20,059 ) (58 ) — (20,279 ) Total property and equipment, net 34 5,040 25 — 5,099 Investments in subsidiaries (equity method) — 23 — (23 ) — Other long-term assets 45 637 — — 682 TOTAL ASSETS $ 8,133 $ 6,304 $ 25 $ (7,917 ) $ 6,545 LIABILITIES AND EQUITY Accounts payable $ 72 $ 513 $ — $ — $ 585 Other current liabilities 193 134 — — 327 Total current liabilities 265 647 — — 912 Intercompany payables — 7,892 2 (7,894 ) — Long-term debt 2,267 — — — 2,267 Pension and other postretirement liabilities 39 — — — 39 Other long-term liabilities 39 206 — — 245 Negative carrying amount of subsidiaries, net 2,441 — — (2,441 ) — Total long-term liabilities 4,786 206 — (2,441 ) 2,551 Commitments and contingencies Total equity (accumulated deficit) 3,082 (2,441 ) 23 2,418 3,082 TOTAL LIABILITIES AND EQUITY $ 8,133 $ 6,304 $ 25 $ (7,917 ) $ 6,545 CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated December 31, 2018 ASSETS Cash and cash equivalents $ 201 $ — $ — $ — $ 201 Accounts receivable, net 4 577 — — 581 Other current assets 8 166 — — 174 Total current assets 213 743 — — 956 Intercompany receivables 7,932 — — (7,932 ) — Natural gas and oil properties, using the full cost method — 24,128 52 — 24,180 Other 197 301 27 — 525 Less: Accumulated depreciation, depletion and amortization (154 ) (19,840 ) (55 ) — (20,049 ) Total property and equipment, net 43 4,589 24 — 4,656 Investments in subsidiaries (equity method) — 24 — (24 ) — Other long-term assets 19 166 — — 185 TOTAL ASSETS $ 8,207 $ 5,522 $ 24 $ (7,956 ) $ 5,797 LIABILITIES AND EQUITY Accounts payable $ 113 $ 496 $ — $ — $ 609 Other current liabilities 115 122 — — 237 Total current liabilities 228 618 — — 846 Intercompany payables — 7,932 — (7,932 ) — Long-term debt 2,318 — — — 2,318 Pension and other postretirement liabilities 46 — — — 46 Other long-term liabilities 54 171 — — 225 Negative carrying amount of subsidiaries, net 3,199 — — (3,199 ) — Total long-term liabilities 5,617 171 — (3,199 ) 2,589 Commitments and contingencies Total equity (accumulated deficit) 2,362 (3,199 ) 24 3,175 2,362 TOTAL LIABILITIES AND EQUITY $ 8,207 $ 5,522 $ 24 $ (7,956 ) $ 5,797
Condensed Consolidating Statements Of Cash Flows	CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) (in millions) Parent Guarantors Non-Guarantors Eliminations Consolidated Six months ended June 30, 2019 Net cash provided by (used in) operating activities $ 1,124 $ 179 $ — $ (760 ) $ 543 Investing activities: Capital investments (1 ) (584 ) (1 ) — (586 ) Proceeds from sale — 26 — — 26 Net cash used in investing activities (1 ) (558 ) (1 ) — (560 ) Financing activities: Intercompany activities (1,140 ) 379 1 760 — Change in bank drafts outstanding (7 ) — — — (7 ) Purchase of treasury stock (21 ) — — — (21 ) Cash paid for tax withholding (1 ) — — — (1 ) Net cash provided by (used in) financing activities (1,169 ) 379 1 760 (29 ) Decrease in cash and cash equivalents (46 ) — — — (46 ) Cash and cash equivalents at beginning of year 201 — — — 201 Cash and cash equivalents at end of period $ 155 $ — $ — $ — $ 155  Six months ended June 30, 2018 Net cash provided by (used in) operating activities $ 276 $ 725 $ — $ (337 ) $ 664 Investing activities: Capital investments (6 ) (678 ) — — (684 ) Other — 9 — — 9 Net cash used in investing activities (6 ) (669 ) — — (675 ) Financing activities: Intercompany activities (287 ) (50 ) — 337 — Payments on long-term debt (1,191 ) — — — (1,191 ) Payments on revolving credit facility (645 ) — — — (645 ) Borrowings under revolving credit facility 1,005 — — — 1,005 Preferred stock dividend (27 ) — — — (27 ) Other (10 ) — — — (10 ) Net cash provided by (used in) financing activities (1,155 ) (50 ) — 337 (868 ) Increase (decrease) in cash and cash equivalents (885 ) 6 — — (879 ) Cash and cash equivalents at beginning of year 914 2 — — 916 Cash and cash equivalents at end of period $ 29 $ 8 $ — $ — $ 37

Basis of Presentation (Narrativ

Basis of Presentation (Narrative) (Details)	6 Months Ended
	Jun. 30, 2019segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of segments	2

Divestitures (Details)

Divestitures (Details) - USD ($) $ in Millions	Dec. 03, 2018	Aug. 30, 2018	Dec. 31, 2018	Mar. 31, 2019	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contractual commitments assumed by buyer					$ 162
Potential amount to be reimbursed to buyer					82
Liability for estimated future payments			$ 88		68	$ 88
Repayments of long-term debt					0		$ 1,191
Treasury stock acquired			201	$ 21		$ 180
Commissions			$ 1
Treasury stock acquired (in shares)			44,000,000	5,260,687		39,061,269
Fayetteville Shale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest prior to disposal		100.00%
Consideration		$ 1,865
Proceeds from disposal	$ 1,650
Adjustment due to differences from economic effective date to close date	$ 215
Non-core leasehold
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration					$ 25
Senior Notes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Repayment of debt			$ 914
Repayments of long-term debt			900
Cash paid for interest			$ 9

Restructuring Charges (Summary

Restructuring Charges (Summary of Restructuring Charges) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 2	$ 18	$ 5	$ 18
E&P
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	2	16	5	16
Workforce Reduction
Restructuring Cost and Reserve [Line Items]
Restructuring liability	0.4		0.4		$ 5
Severance (including payroll taxes)	1	17	3	17
Office consolidation	1	0	2	0
Professional fees	0	1	0	1
Total restructuring charges	2	18	5	18
Workforce Reduction | E&P
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 2	$ 16	$ 5	$ 2

Restructuring Charges (Restruct

Restructuring Charges (Restructuring Rollforward) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Reserve [Roll Forward]
Additions	$ 2	$ 18	$ 5	$ 18
Workforce Reduction
Restructuring Reserve [Roll Forward]
Liability at December 31, 2018			5
Additions	2	$ 18	5	$ 18
Distributions			(10)
Liability at June 30, 2019	$ 0.4		$ 0.4

Leases (New Accounting) (Detail

Leases (New Accounting) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	$ 103
Lease liability balance	$ 103
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset		$ 105
Lease liability balance		$ 105

Revenue Recognition (Narrative)

Revenue Recognition (Narrative) (Details) - USD ($)	1 Months Ended	6 Months Ended
	Dec. 31, 2018	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Contract asset associated with revenues from contracts with customers		$ 0
Contract liability associated with revenues from contracts with customers		$ 0
Minimum | NGL sales
Disaggregation of Revenue [Line Items]
Payment terms		30 days
Minimum | Marketing
Disaggregation of Revenue [Line Items]
Payment terms		30 days
Minimum | Gas gathering
Disaggregation of Revenue [Line Items]
Payment terms		30 days
Maximum | NGL sales
Disaggregation of Revenue [Line Items]
Payment terms		60 days
Maximum | Marketing
Disaggregation of Revenue [Line Items]
Payment terms		60 days
Maximum | Gas gathering
Disaggregation of Revenue [Line Items]
Payment terms		60 days
Fayetteville Shale
Disaggregation of Revenue [Line Items]
Percentage of assets sold	100.00%

Leases (Narrative) (Details)

Leases (Narrative) (Details) $ in Millions	Jun. 30, 2019USD ($)
Leases [Abstract]
Operating leases not yet commenced (less than)	$ 4

Revenue Recognition (Disaggrega

Revenue Recognition (Disaggregation of Revenue by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 667	$ 816	$ 1,657	$ 1,736
E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	380	527	931	1,170
Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	287	289	726	566
Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	371	520	913	1,157
Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	626	797	1,567	1,693
Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	330	501	823	1,114
Intersegment Revenues | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	(9)	(7)	(18)	(13)
Intersegment Revenues | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	339	508	841	1,127
Gas sales
Disaggregation of Revenue [Line Items]
Total operating revenues	275	407	705	947
Gas sales | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	267	400	688	935
Gas sales | Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
Gas sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	(8)	(7)	(17)	(12)
Oil sales
Disaggregation of Revenue [Line Items]
Total operating revenues	47	44	86	79
Oil sales | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	46	44	85	78
Oil sales | Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
Oil sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	(1)	0	(1)	(1)
NGL sales
Disaggregation of Revenue [Line Items]
Total operating revenues	58	75	139	140
NGL sales | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	58	75	139	140
NGL sales | Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
NGL sales | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
Marketing
Disaggregation of Revenue [Line Items]
Total operating revenues	287	265	725	518
Marketing | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	0	0	0	0
Marketing | Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	626	728	1,566	1,557
Marketing | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	339	463	841	1,039
Marketing | Intersegment Revenues | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues	339	463	841	1,039
Gas gathering
Disaggregation of Revenue [Line Items]
Total operating revenues	0	24	0	48
Gas gathering | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues		0		0
Gas gathering | Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues		69		136
Gas gathering | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues		45		88
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 0	1	2	4
Other | Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues		1	1	4
Other | Operating Segments | Midstream
Disaggregation of Revenue [Line Items]
Total operating revenues		0	1	0
Other | Intersegment Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues		$ 0	$ 0	$ 0

Leases (Components of Lease Cos

Leases (Components of Lease Costs) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 22
Short-term lease cost	31
Variable lease cost	0
Total lease cost	$ 53

Revenue Recognition (Disaggre_2

Revenue Recognition (Disaggregation of Revenue on Geographic Basis) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 667	$ 816	$ 1,657	$ 1,736
E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	380	527	931	1,170
Operating Segments | E&P
Disaggregation of Revenue [Line Items]
Total operating revenues	371	520	913	1,157
Operating Segments | E&P | Northeast Appalachia
Disaggregation of Revenue [Line Items]
Total operating revenues	217	213	565	540
Operating Segments | E&P | Southwest Appalachia
Disaggregation of Revenue [Line Items]
Total operating revenues	153	166	346	322
Operating Segments | E&P | Fayetteville Shale
Disaggregation of Revenue [Line Items]
Total operating revenues	0	139	0	291
Operating Segments | E&P | Other
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 1	$ 2	$ 2	$ 4

Leases (Supplemental Informatio

Leases (Supplemental Information) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 22
Right-of use assets obtained in exchange for new operating liabilities	6
Right-of-use asset	103
Lease liability balance: (in millions)
Short-term operating leases	47
Long-term operating leases	56
Total operating leases	$ 103
Weighted average remaining lease term	3 years 9 months 18 days
Weighted average discount rate	6.28%

Revenue Recognition (Reconcilia

Revenue Recognition (Reconciliation of Accounts Receivable) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Receivables from contracts with customers	$ 238	$ 494
Other accounts receivable	120	87
Total accounts receivable	$ 358	$ 581

Leases (Maturity Schedule) (Det

Leases (Maturity Schedule) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Leases [Abstract]
2019	$ 22	$ 38
2020	42	28
2021	19	14
2022	10	6
2023	8	5
2024	5
Thereafter 2023		4
Thereafter 2024	9
Total undiscounted lease liability	115	$ 95
Imputed interest	(12)
Total discounted lease liability	$ 103

Cash and Cash Equivalents (Summ

Cash and Cash Equivalents (Summary of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Cash	$ 71	$ 32
Marketable securities	69	169
Other cash equivalents	15	0
Total	$ 155	$ 201

Natural Gas and Oil Properties

Natural Gas and Oil Properties (Narrative) (Details)	6 Months Ended
	Jun. 30, 2019derivative_position$ / bbl$ / MMBTU	Jun. 30, 2018derivative_position$ / bbl$ / MMBTU
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
Number of hedge positions designated for hedge accounting | derivative_position	0	0
Natural Gas | Henry Hub
Natural Gas and Oil Properties [Line Items]
Full cost ceiling test, price per MMBtu (in dollars per MMBtu) | $ / MMBTU	3.02	2.92
Oil | West Texas Intermediate
Natural Gas and Oil Properties [Line Items]
Full cost ceiling test, price per barrel (in dollars per bbl)	61.39	54.15
NGL | West Texas Intermediate
Natural Gas and Oil Properties [Line Items]
Full cost ceiling test, price per barrel (in dollars per bbl)	16.35	15.56

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			3 Months Ended	6 Months Ended
	Dec. 31, 2018	Jan. 31, 2018	Jan. 31, 2015	Mar. 31, 2019	Dec. 31, 2018	Jan. 12, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Treasury stock acquired (in shares)	44,000,000			5,260,687	39,061,269
Treasury stock acquired	$ 201			$ 21	$ 180
Treasury stock acquired, average cost per share (in dollars per share)				$ 3.84	$ 4.63
Depositary Shares
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued (in shares)			34,500,000
Dividend payment		$ 27
Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Shares issued upon conversion (in shares)						74,998,614

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended					6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018		Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 138	$ 594	$ 51	[1]	$ 208	$ 732	$ 259	[1]
Participating securities - mandatory convertible preferred stock	0		0			0	2
Net Income Attributable to Common Stock	$ 138		$ 51			$ 732	$ 257
Number of common shares:
Weighted average outstanding (in shares)	539,005,941		581,159,200			539,362,984	576,255,744
Issued upon assumed exercise of outstanding stock options (in shares)	0		0			0	0
Effect of issuance of non-vested restricted common stock (in shares)	311,732		480,580			481,948	683,562
Effect of issuance of non-vested performance units (in shares)	629,380		1,238,326			779,810	1,283,434
Weighted average and potential dilutive outstanding (in shares)	539,947,053		582,878,106			540,624,742	578,222,740
Earnings per common share
Basic (in dollars per share)	$ 0.26		$ 0.09			$ 1.36	$ 0.45
Diluted (in dollars per share)	$ 0.26		$ 0.09			$ 1.35	$ 0.44
[1]	In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.

Earnings Per Share (Schedule _2

Earnings Per Share (Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	7,129,733	5,211,515	7,195,007	11,111,716
Unexercised stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	5,114,763	0	5,121,663	0
Unvested share-based payment
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,773,074	4,335,715	1,822,346	5,152,847
Performance units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	241,896	875,800	250,998	986,585
Mandatory convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0	0	0	4,972,284

Derivatives and Risk Manageme_3

Derivatives and Risk Management (Schedule of Derivative Instruments Notional Amount, Weighted Average Contract Prices and Fair Value) (Details) - Not Designated as Hedging Instrument MBbls in Thousands, $ in Millions, Bcf in Billions	6 Months Ended
	Jun. 30, 2019USD ($)$ / bbl$ / MMBTUMBblsBcf
Sold Fixed Price Swaps - 2019 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	131
Average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.92
Fair Value	$ 75
Sold Fixed Price Swaps - 2019 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	1,003
Average price (in dollars per MMBtu, Bbl) | $ / bbl	60.89
Fair Value	$ 4
Sold Fixed Price Swaps - 2019 | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	1,955
Average price (in dollars per MMBtu, Bbl) | $ / bbl	30.18
Fair Value	$ 14
Sold Fixed Price Swaps - 2019 | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	1,858
Average price (in dollars per MMBtu, Bbl) | $ / bbl	13.90
Fair Value	$ 10
Two-way Costless-collars - 2019 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	25
Fair Value	$ 13
Two-way Costless-collars - 2019 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	764
Fair Value	$ 4
Two-way Costless-collars - 2019 | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	276
Fair Value	$ 1
Two-way Costless-collars - 2019 Purchased Puts | Propane
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	25.62
Two-way Costless-collars - 2019 Sold Calls | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.92
Two-way Costless-collars - 2019 Sold Calls | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	67.16
Two-way Costless-collars - 2019 Sold Calls | Propane
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	28.77
Three-way Costless-collars - 2019 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	67
Fair Value	$ 22
Three-way Costless-collars - 2019 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	276
Three-way Costless-collars - 2019 Sold Calls | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.22
Three-way Costless-collars - 2019 Sold Calls | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	63.67
Financial protection on production - 2019 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	223
Fair Value	$ 110
Financial protection on production - 2019 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	2,043
Fair Value	$ 8
Financial protection on production - 2019 | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	2,231
Fair Value	$ 15
Sold Fixed Price Swaps - 2020 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	24
Average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.88
Fair Value	$ 8
Sold Fixed Price Swaps - 2020 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	1,556
Average price (in dollars per MMBtu, Bbl) | $ / bbl	60.18
Fair Value	$ 7
Sold Fixed Price Swaps - 2020 | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	2,196
Average price (in dollars per MMBtu, Bbl) | $ / bbl	26.97
Fair Value	$ 6
Sold Fixed Price Swaps - 2020 | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	732
Average price (in dollars per MMBtu, Bbl) | $ / bbl	13.49
Fair Value	$ 2
Two-way Costless-collars - 2020 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	366
Fair Value	$ 3
Two-way Costless-collars - 2020 | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	366
Fair Value	$ 1
Two-way Costless-collars - 2020 Sold Calls | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	69.80
Two-way Costless-collars - 2020 Sold Calls | Propane
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	29.40
Three-Way Costless Collars - 2020 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	148
Fair Value	$ 10
Three-Way Costless Collars - 2020 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	641
Fair Value	$ 1
Three-way Costless-collars - 2020 Sold Calls | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.97
Three-way Costless-collars - 2020 Sold Calls | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	63.36
Financial protection on production - 2020 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	172
Fair Value	$ 18
Financial protection on production - 2020 | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	2,563
Fair Value	$ 11
Financial protection on production - 2020 | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	2,562
Fair Value	$ 7
Three-way Costless-collars - 2021 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	37
Fair Value	$ (1)
Three-Way Costless Collars - 2021 Sold Calls | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.93
Sold Basis Swaps - 2019 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	80
Basis differential per MMBtu | $ / MMBTU	(0.45)
Fair Value	$ (6)
Sold Basis Swaps - 2020 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	132
Basis differential per MMBtu | $ / MMBTU	(0.34)
Fair Value	$ (10)
Sold Basis Swaps - 2021 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	28
Basis differential per MMBtu | $ / MMBTU	(0.51)
Fair Value	$ (1)
Sold Basis Swaps | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	240
Fair Value	$ (17)
Purchased fixed price swaps | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	138
Average price (in dollars per MMBtu, Bbl) | $ / bbl	69.10
Fair Value	$ (1)
Sold fixed price swaps | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | MBbls	1,141
Average price (in dollars per MMBtu, Bbl) | $ / bbl	61.88
Fair Value	$ 5
Purchased Call Options 2019 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	17
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.50
Fair Value	$ 0
Purchased Call Options - 2020 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	68
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.63
Fair Value	$ 2
Purchased Call Options - 2021 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	57
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.52
Fair Value	$ 2
Purchased call options | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	142
Fair Value	$ 4
Sold Call Options - 2019 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	26
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.50
Fair Value	$ 0
Sold Call Options - 2020 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	137
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.39
Fair Value	$ (8)
Sold Call Options - 2021 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	114
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.33
Fair Value	$ (8)
Sold call options | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	277
Fair Value	$ (16)
Purchased Fixed Price Swaps, Storage, 2019
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	1
Average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.87
Basis differential per MMBtu | $ / MMBTU	0
Fair Value	$ (1,000)
Purchased Basis Swaps Storage, 2019
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	1
Average price (in dollars per MMBtu, Bbl) | $ / MMBTU	0
Basis differential per MMBtu | $ / MMBTU	(0.53)
Fair Value	$ 0
Storage 2019
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	2
Fair Value	$ (1,000)
Fixed Price Swap, Storage, 2020
Derivative [Line Items]
Volume (Bcf, MBbls) | Bcf	1
Average price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.14
Basis differential per MMBtu | $ / MMBTU	0
Fair Value	$ 0
Short Puts | Three-way Costless-collars - 2019 Sold Puts | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.47
Short Puts | Three-way Costless-collars - 2019 Sold Puts | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	45
Short Puts | Three-way Costless-collars - 2020 Sold Puts | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.36
Short Puts | Three-way Costless-collars - 2020 Sold Puts | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	45
Short Puts | Three-Way Costless Collars - 2021 Sold Puts | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.35
Purchased Puts | Two-way Costless-collars - 2019 Purchased Puts | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.78
Purchased Puts | Two-way Costless-collars - 2019 Purchased Puts | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	61.45
Purchased Puts | Three-way Costless-collars - 2019 Purchased Puts | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.88
Purchased Puts | Three-way Costless-collars - 2019 Purchased Puts | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	55
Purchased Puts | Two-way Costless-collars - 2020 Purchased Puts | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	60
Purchased Puts | Two-way Costless-collars - 2020 Purchased Puts | Propane
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	25.20
Purchased Puts | Three-way Costless-collars - 2020 Purchased Puts | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.67
Purchased Puts | Three-way Costless-collars - 2020 Purchased Puts | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	55
Purchased Puts | Three-Way Costless Collars - 2021 Purchased Puts | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.60

Derivatives and Risk Manageme_4

Derivatives and Risk Management (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Commodities
Derivative [Line Items]
Derivative assets	$ 150
Interest rate swaps
Derivative [Line Items]
Derivative assets		$ 1
Derivative liabilities	1
Not Designated as Hedging Instrument | Interest rate swaps
Derivative [Line Items]
Notional amount	$ 170

Derivatives and Risk Manageme_5

Derivatives and Risk Management (Balance Sheet Classification of Derivative Financial Instruments) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative assets	$ 261	$ 191
Derivative liabilities	112	139
Not Designated as Hedging Instrument | Storage - fixed price swap | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	0
Not Designated as Hedging Instrument | Interest rate swaps | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	0	1
Not Designated as Hedging Instrument | Interest rate swaps | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	0
Natural Gas | Purchased call options
Derivatives, Fair Value [Line Items]
Premium paid	1
Natural Gas | Not Designated as Hedging Instrument | Fixed price swaps | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	79	32
Natural Gas | Not Designated as Hedging Instrument | Fixed price swaps | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	4	6
Natural Gas | Not Designated as Hedging Instrument | Fixed price swaps | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	9
Natural Gas | Not Designated as Hedging Instrument | Fixed price swaps | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	1
Natural Gas | Not Designated as Hedging Instrument | Two-way costless collars | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	13	11
Natural Gas | Not Designated as Hedging Instrument | Two-way costless collars | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	7
Natural Gas | Not Designated as Hedging Instrument | Three-way costless collars | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	65	41
Natural Gas | Not Designated as Hedging Instrument | Three-way costless collars | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	31	34
Natural Gas | Not Designated as Hedging Instrument | Three-way costless collars | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	37	33
Natural Gas | Not Designated as Hedging Instrument | Three-way costless collars | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	28	35
Natural Gas | Not Designated as Hedging Instrument | Basis swaps | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	5	8
Natural Gas | Not Designated as Hedging Instrument | Basis swaps | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	2	3
Natural Gas | Not Designated as Hedging Instrument | Basis swaps | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	19	18
Natural Gas | Not Designated as Hedging Instrument | Basis swaps | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	5	4
Natural Gas | Not Designated as Hedging Instrument | Sold call options | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	5	3
Natural Gas | Not Designated as Hedging Instrument | Sold call options | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	11	19
Natural Gas | Not Designated as Hedging Instrument | Purchased call options | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	1	0
Premium paid	1
Natural Gas | Not Designated as Hedging Instrument | Purchased call options | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	4	6
Oil | Not Designated as Hedging Instrument | Purchased fixed price swaps | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	6
Oil | Not Designated as Hedging Instrument | Fixed price swaps | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	7	13
Oil | Not Designated as Hedging Instrument | Fixed price swaps | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	4	6
Oil | Not Designated as Hedging Instrument | Two-way costless collars | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	6	6
Oil | Not Designated as Hedging Instrument | Two-way costless collars | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	2	5
Oil | Not Designated as Hedging Instrument | Two-way costless collars | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	0
Oil | Not Designated as Hedging Instrument | Two-way costless collars | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	1
Oil | Not Designated as Hedging Instrument | Three-way costless collars | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	2	0
Oil | Not Designated as Hedging Instrument | Three-way costless collars | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	2	0
Oil | Not Designated as Hedging Instrument | Three-way costless collars | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	2	0
Oil | Not Designated as Hedging Instrument | Three-way costless collars | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	0
Propane | Not Designated as Hedging Instrument | Fixed price swaps | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	18	11
Propane | Not Designated as Hedging Instrument | Fixed price swaps | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	2	0
Propane | Not Designated as Hedging Instrument | Two-way costless collars | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	2	0
Ethane | Not Designated as Hedging Instrument | Fixed price swaps | Derivative assets
Derivatives, Fair Value [Line Items]
Derivative assets	11	7
Ethane | Not Designated as Hedging Instrument | Fixed price swaps | Other long-term assets
Derivatives, Fair Value [Line Items]
Derivative assets	1	1
Ethane | Not Designated as Hedging Instrument | Fixed price swaps | Derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 0	$ 3

Derivatives and Risk Manageme_6

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	$ 118	$ (56)	$ 96	$ (54)
Settled Gain (Loss) on Derivatives Recognized in Earnings	34	20	24	11
Total gain (loss) on derivatives	152	(36)	120	(43)
Purchased fixed price swaps | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	1	0	5	0
Settled Gain (Loss) on Derivatives Recognized in Earnings	(1)	0	(2)	0
Fixed price swaps | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	5	0	(8)	0
Settled Gain (Loss) on Derivatives Recognized in Earnings	2	0	4	0
Fixed price swaps | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	57	(26)	55	(29)
Settled Gain (Loss) on Derivatives Recognized in Earnings	14	13	8	13
Fixed price swaps | Propane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	13	(12)	9	(9)
Settled Gain (Loss) on Derivatives Recognized in Earnings	7	(1)	9	(1)
Fixed price swaps | Ethane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	0	(2)	7	(2)
Settled Gain (Loss) on Derivatives Recognized in Earnings	5	0	6	0
Two-way costless collars | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	4	0	(3)	0
Settled Gain (Loss) on Derivatives Recognized in Earnings	1	0	2	0
Two-way costless collars | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	10	(1)	9	2
Settled Gain (Loss) on Derivatives Recognized in Earnings	3	0	2	4
Two-way costless collars | Propane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	2	0	2	0
Three-way costless collars | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	1	0	1	0
Three-way costless collars | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	22	(24)	24	(29)
Settled Gain (Loss) on Derivatives Recognized in Earnings	8	12	4	19
Basis swaps | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	4	(4)	(6)	16
Settled Gain (Loss) on Derivatives Recognized in Earnings	(4)	(3)	(8)	(24)
Purchased call options | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(2)	(12)	(2)	4
Settled Gain (Loss) on Derivatives Recognized in Earnings	0	0	0	2
Amortization of premium paid				1
Sold call options | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	0	(6)	0	(6)
Settled Gain (Loss) on Derivatives Recognized in Earnings	0	(1)	0	(1)
Sold call options | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	4	31	6	(3)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(1)	0	(1)	(1)
Storage - fixed price swap
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(1)	0	(1)	0
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	$ (2)	$ 0	$ (2)	$ 2

Reclassifications from Accumu_3

Reclassifications from Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning	$ 2,937	$ 2,193	$ 2,362	$ 1,979
Net current-period other comprehensive income	4	0	4	0
Balance ending	3,082	2,250	3,082	2,250
Pension and Other Postretirement
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning			(22)
Other comprehensive income before reclassifications			0
Amounts reclassified from other comprehensive income			4
Net current-period other comprehensive income			4
Balance ending	(18)		(18)
Foreign Currency
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning			(14)
Other comprehensive income before reclassifications			0
Amounts reclassified from other comprehensive income			0
Net current-period other comprehensive income			0
Balance ending	(14)		(14)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning	(36)	(44)	(36)	(44)
Other comprehensive income before reclassifications			0
Amounts reclassified from other comprehensive income			4
Net current-period other comprehensive income	4		4
Balance ending	$ (32)	$ (44)	$ (32)	$ (44)

Reclassifications from Accumu_4

Reclassifications from Accumulated Other Comprehensive Income (Loss) (Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended					6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018		Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income, Net	$ (6)		$ 3			$ (5)	$ 2
Provision for income taxes	15		0			(411)	0
Net income	$ 138	$ 594	$ 51	[1]	$ 208	732	$ 259	[1]
Amount Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income						4
Amortization of prior service cost and net loss | Amount Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Income, Net						5
Provision for income taxes						1
Net income						$ 4
[1]	In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Amount and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments, net	$ 149	$ 52
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	155	201
Derivative instruments, net	149	52
Carrying Amount | Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	2,342	2,342
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	155	201
Derivative instruments, net	149	52
Fair Value | Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	2,220	2,190
2018 revolving credit facility due April 2023 | Carrying Amount | Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit facility	0	0
2018 revolving credit facility due April 2023 | Fair Value | Long-term debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Credit facility	0	$ 0
Purchased call options | Natural Gas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Premium paid	$ 1

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details)	Jun. 30, 2019	Jul. 31, 2018	Jul. 31, 2016	Jan. 31, 2015
Long-term debt | 4.05% Senior Notes due January 2020
Debt Instrument [Line Items]
Stated interest rate	6.05%	5.30%	5.80%	4.05%

Fair Value Measurements (Summar

Fair Value Measurements (Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 149	$ 52
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	149	52
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
Fixed price swaps | Natural Gas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	83	38
Derivative liabilities		(10)
Fixed price swaps | Natural Gas | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities		0
Fixed price swaps | Natural Gas | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	83	38
Derivative liabilities		(10)
Fixed price swaps | Natural Gas | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities		0
Fixed price swaps | Oil
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	11	19
Fixed price swaps | Oil | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Fixed price swaps | Oil | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	11	19
Fixed price swaps | Oil | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Fixed price swaps | Propane
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	20	11
Fixed price swaps | Propane | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Fixed price swaps | Propane | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	20	11
Fixed price swaps | Propane | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Fixed price swaps | Ethane
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	12	8
Derivative liabilities		(3)
Fixed price swaps | Ethane | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities		0
Fixed price swaps | Ethane | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	12	8
Derivative liabilities		(3)
Fixed price swaps | Ethane | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities		0
Two-way costless collars | Natural Gas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	13	11
Derivative liabilities		(7)
Two-way costless collars | Natural Gas | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities		0
Two-way costless collars | Natural Gas | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	13	11
Derivative liabilities		(7)
Two-way costless collars | Natural Gas | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities		0
Two-way costless collars | Oil
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	8	11
Derivative liabilities	(1)	(1)
Two-way costless collars | Oil | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Two-way costless collars | Oil | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	8	11
Derivative liabilities	(1)	(1)
Two-way costless collars | Oil | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Two-way costless collars | Propane
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2
Two-way costless collars | Propane | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Two-way costless collars | Propane | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2
Two-way costless collars | Propane | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Three-way costless collars | Natural Gas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	96	75
Derivative liabilities	(65)	(68)
Three-way costless collars | Natural Gas | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Three-way costless collars | Natural Gas | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	96	75
Derivative liabilities	(65)	(68)
Three-way costless collars | Natural Gas | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Three-way costless collars | Oil
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	4
Derivative liabilities	(3)
Three-way costless collars | Oil | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Derivative liabilities	0
Three-way costless collars | Oil | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	4
Derivative liabilities	(3)
Three-way costless collars | Oil | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0
Derivative liabilities	0
Basis swaps | Natural Gas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7	11
Derivative liabilities	(24)	(22)
Basis swaps | Natural Gas | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Basis swaps | Natural Gas | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7	11
Derivative liabilities	(24)	(22)
Basis swaps | Natural Gas | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Purchased call options | Natural Gas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	5	6
Purchased call options | Natural Gas | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Purchased call options | Natural Gas | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	5	6
Purchased call options | Natural Gas | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Interest rate swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		1
Derivative liabilities	(1)
Interest rate swaps | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Derivative liabilities	0
Interest rate swaps | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		1
Derivative liabilities	(1)
Interest rate swaps | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		0
Derivative liabilities	0
Purchased fixed price swaps | Oil
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(1)	(6)
Purchased fixed price swaps | Oil | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Purchased fixed price swaps | Oil | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(1)	(6)
Purchased fixed price swaps | Oil | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Sold call options | Natural Gas
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(16)	(22)
Sold call options | Natural Gas | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Sold call options | Natural Gas | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(16)	(22)
Sold call options | Natural Gas | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	$ 0
Storage - fixed price swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(1)
Storage - fixed price swap | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0
Storage - fixed price swap | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	(1)
Storage - fixed price swap | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	$ 0

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at beginning of period	$ 0	$ 22	$ 0	$ 22
Included in earnings	0	(8)	0	(17)
Settlements	0	(8)	0	1
Transfers into/out of Level 3	0	(6)	0	(6)
Balance at end of period	0	0	0	0
Change in gains (losses) included in earnings relating to derivatives still held as of June 30	$ 0	$ 0	$ 0	0
Natural Gas | Call Option
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Amortization of premium paid				$ 1

Debt (Components of Debt) (Deta

Debt (Components of Debt) (Details) - USD ($) $ in Millions	1 Months Ended		6 Months Ended	12 Months Ended
	Jul. 31, 2016	Feb. 29, 2016	Jun. 30, 2019	Dec. 31, 2018	Jul. 31, 2018	Jan. 31, 2015
Debt Instrument [Line Items]
Debt Instrument, long-term debt			$ 2,290
Debt Instrument			2,342	$ 2,342
Unamortized Issuance Expense			(22)	(23)
Unamortized Debt Discount			(1)	(1)
Total, current portion of long-term debt			52	0
Total, long-term debt			2,267	2,318
Total debt			2,319	2,318
Unamortized issuance expense			22	23
Line of Credit | 2018 revolving credit facility, due April 2023
Debt Instrument [Line Items]
Debt Instrument, long-term debt			0
Unamortized Issuance Expense			0
Unamortized Debt Discount			0
Total, long-term debt			$ 0
Variable interest rate			3.88%
Unamortized issuance expense			$ 0
Line of Credit | 2018 term loan facility, due April 2023
Debt Instrument [Line Items]
Debt Instrument				0
Unamortized Issuance Expense				0
Unamortized Debt Discount				0
Total debt				$ 0
Variable interest rate				3.92%
Unamortized issuance expense				$ 0
Senior Notes
Debt Instrument [Line Items]
Debt Instrument, current portion of long-term debt			52
Unamortized Issuance Expense			0
Unamortized Debt Discount			0
Total, current portion of long-term debt			52
Unamortized issuance expense			0
Senior Notes | 4.05% Senior Notes due January 2020
Debt Instrument [Line Items]
Debt Instrument, current portion of long-term debt			52
Debt Instrument				52
Unamortized Issuance Expense			0	0
Unamortized Debt Discount			0	0
Total, current portion of long-term debt			$ 52
Total debt				52
Stated interest rate			4.05%
Unamortized issuance expense			$ 0	0
Senior Notes | 4.10% Senior Notes due March 2022
Debt Instrument [Line Items]
Debt Instrument, long-term debt			213
Debt Instrument				213
Unamortized Issuance Expense			(1)	(1)
Unamortized Debt Discount			0	0
Total, long-term debt			$ 212
Total debt				212
Stated interest rate			4.10%
Unamortized issuance expense			$ 1	1
Senior Notes | 4.95% Senior Notes due January 2025
Debt Instrument [Line Items]
Debt Instrument, long-term debt			927
Debt Instrument				927
Unamortized Issuance Expense			(7)	(7)
Unamortized Debt Discount			(1)	(1)
Total, long-term debt			$ 919
Total debt				919
Stated interest rate			4.95%
Unamortized issuance expense			$ 7	7
Senior Notes | 7.50% Senior Notes due April 2026
Debt Instrument [Line Items]
Debt Instrument, long-term debt			650
Debt Instrument				650
Unamortized Issuance Expense			(8)	(8)
Unamortized Debt Discount			0	0
Total, long-term debt			$ 642
Total debt				642
Stated interest rate			7.50%
Unamortized issuance expense			$ 8	8
Senior Notes | 7.75% Senior Notes due October 2027
Debt Instrument [Line Items]
Debt Instrument, long-term debt			500
Debt Instrument				500
Unamortized Issuance Expense			(6)	(7)
Unamortized Debt Discount			0	0
Total, long-term debt			$ 494
Total debt				493
Stated interest rate			7.75%
Unamortized issuance expense			$ 6	7
Long-term debt | 4.05% Senior Notes due January 2020
Debt Instrument [Line Items]
Stated interest rate	5.80%		6.05%		5.30%	4.05%
Long-term debt | 4.95% Senior Notes due January 2025
Debt Instrument [Line Items]
Stated interest rate	6.70%		6.95%		6.20%	4.95%
LIBOR | Senior Notes
Debt Instrument [Line Items]
Increase in basis spread	1.75%	1.75%
Other long-term assets | Line of Credit | 2018 revolving credit facility, due April 2023
Debt Instrument [Line Items]
Unamortized Issuance Expense			$ (10)	(11)
Unamortized issuance expense			$ 10	$ 11

Debt (2018 Revolving Credit Fac

Debt (2018 Revolving Credit Facility - Narrative) (Details) - USD ($)	Apr. 26, 2018	Apr. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Apr. 04, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt instrument			$ 2,342,000,000		$ 2,342,000,000			$ 2,342,000,000
Loss on early extinguishment of debt			0	$ 8,000,000	0	$ 8,000,000
Unamortized issuance expense			22,000,000		$ 22,000,000			$ 23,000,000
Subsidiary ownership					100.00%
Letter of Credit
Debt Instrument [Line Items]
Current aggregate commitment			172,000,000		$ 172,000,000
Long-term debt | 2016 Credit Facility
Debt Instrument [Line Items]
Debt instrument		$ 743,000,000
Long-term debt | 2018 revolving credit facility due April 2023
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 3,500,000,000
Current borrowing capacity			2,100,000,000		2,100,000,000		$ 2,100,000,000
Current aggregate commitment			2,000,000,000		2,000,000,000
Limit on securing indebtedness			$ 2,000,000,000		$ 2,000,000,000
Percentage of consolidated net tangible assets		25.00%
Minimum interest coverage ratio		1
Long-term debt | 2018 revolving credit facility due April 2023 | Maximum
Debt Instrument [Line Items]
Leverage ratio, percentage of credit limit		10.00%
Leverage ratio, amount of credit limit		$ 150,000,000
Long-term debt | 2018 revolving credit facility due April 2023 | Eurodollar | Minimum
Debt Instrument [Line Items]
Basis points		1.50%
Long-term debt | 2018 revolving credit facility due April 2023 | Eurodollar | Maximum
Debt Instrument [Line Items]
Basis points		2.50%
Long-term debt | 2018 revolving credit facility due April 2023 | Base Rate | Minimum
Debt Instrument [Line Items]
Basis points		0.50%
Long-term debt | 2018 revolving credit facility due April 2023 | Base Rate | Maximum
Debt Instrument [Line Items]
Basis points		1.50%
2016 Term Loan due December 2020 | Long-term debt
Debt Instrument [Line Items]
Debt instrument		$ 1,191,000,000
Secured term loan | Long-term debt
Debt Instrument [Line Items]
Debt instrument	$ 743,000,000
Extinguishment of debt	1,191,000,000
Loss on early extinguishment of debt	8,000,000
Unamortized issuance expense	$ 4,000,000
June 30, 2018 Through March 31, 2019 | Long-term debt | 2018 revolving credit facility due April 2023 | Maximum
Debt Instrument [Line Items]
Leverage ratio		4.50
June 30, 2019 Through March 31, 2020 | Long-term debt | 2018 revolving credit facility due April 2023 | Maximum
Debt Instrument [Line Items]
Leverage ratio		4.25
After June 30, 2020 | Long-term debt | 2018 revolving credit facility due April 2023 | Maximum
Debt Instrument [Line Items]
Leverage ratio		4

Debt (Senior Notes - Narrative)

Debt (Senior Notes - Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Jul. 31, 2016	Feb. 29, 2016	Jan. 31, 2015	Jun. 30, 2019	Jul. 31, 2018
Senior Notes | LIBOR
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%	1.75%
4.05% Senior Notes due January 2020 | Long-term debt
Debt Instrument [Line Items]
Senior notes			$ 850
Stated interest rate	5.80%		4.05%	6.05%	5.30%
4.05% Senior Notes due January 2020 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate				4.05%
4.95% Senior Notes due January 2025 | Long-term debt
Debt Instrument [Line Items]
Senior notes			$ 1,000
Stated interest rate	6.70%		4.95%	6.95%	6.20%
4.95% Senior Notes due January 2025 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate				4.95%

Commitments and Contingencies_2

Commitments and Contingencies (Narrative) (Details) $ in Millions	Jul. 31, 2019USD ($)	Jun. 30, 2019USD ($)lawsuit	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Commitments And Contingencies [Line Items]
Obligation under transportation agreements		$ 8,467
Guarantee obligations relative to the firms transportation agreements and gathering project and services		362
Contractual commitments assumed by buyer		162
Potential amount to be reimbursed to buyer		82
Liability for estimated future payments		68		$ 88
Liability Associated With Indemnification Obligation		0
Operating lease commitment		115		$ 95
Pending regulatory approval and/or construction
Commitments And Contingencies [Line Items]
Obligation under transportation agreements		$ 966
Appalachian Basin
Commitments And Contingencies [Line Items]
Obligation under transportation agreements			$ 357
Reimbursed by seller			$ 133
Subsequent event
Commitments And Contingencies [Line Items]
Operating lease commitment	$ 88
Term of contract	10 years
Arkansas Royalty Litigation
Commitments And Contingencies [Line Items]
Number of class action lawsuits | lawsuit		3
Arkansas Royalty Litigation | Arkansas
Commitments And Contingencies [Line Items]
Number of class action lawsuits | lawsuit		2
Arkansas Royalty Litigation | Eastern Arkansas
Commitments And Contingencies [Line Items]
Number of class action lawsuits | lawsuit		1

Commitments and Contingencies_3

Commitments and Contingencies (Schedule of Future Obligation under Transportation Agreements) (Details) $ in Millions	Jun. 30, 2019USD ($)
Other Commitments [Line Items]
Total	$ 8,467
Less than 1 year	711
1 to 3 years	1,382
3 to 5 years	1,218
5 to 8 years	1,707
More than 8 years	3,449
Infrastructure currently in service
Other Commitments [Line Items]
Total	7,501
Less than 1 year	702
1 to 3 years	1,304
3 to 5 years	1,097
5 to 8 years	1,511
More than 8 years	2,887
Pending regulatory approval and/or construction
Other Commitments [Line Items]
Total	966
Less than 1 year	9
1 to 3 years	78
3 to 5 years	121
5 to 8 years	196
More than 8 years	$ 562

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Effective tax rate	10.00%	0.00%	(128.00%)	0.00%
Increase (decrease) in valuation allowance			$ 411
Valuation allowance related to operating loss	$ 87		$ 87

Pension Plan and Other Postre_3

Pension Plan and Other Postretirement Benefits (Pension and Other Postretirement Benefit Costs) (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 3	$ 4	$ 6
Interest cost	1	1	2	3
Expected return on plan assets	(1)	(2)	(3)	(4)
Amortization of prior service cost	0	0	0	0
Amortization of net loss	0	0	1	0
Settlement loss	4	0	4	0
Net periodic benefit cost	$ 6	$ 2	$ 8	$ 5

Pension Plan and Other Postre_4

Pension Plan and Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended			12 Months Ended
	Dec. 31, 2018	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Employer contributions					$ 9
Additional contributions for remainder of year		$ 3			3
Treasury stock acquired (in shares)	44,000,000		5,260,687			39,061,269
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement loss		4		$ 0	4		$ 0
Payments for pension plan					16
Net periodic benefit cost (gain)		6		2	8		5
Benefit obligation	$ 34	28			28	$ 34		$ 34
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (gain)		1		$ 1	1		$ 2
Benefit obligation	$ 13	$ 13			$ 13	$ 13		$ 13
Non-Qualified Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Treasury stock acquired (in shares)					5,115			10,653

Stock-Based Compensation (Sched

Stock-Based Compensation (Schedule of Stock-Based Compensation Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation [Abstract]
Stock-based compensation cost – expensed	$ 4	$ 8	$ 11	$ 13
Stock-based compensation cost – capitalized	$ 2	$ 4	$ 6	$ 7

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019
Share-based Compensation [Line Items]
Service period			3 years
Stock options
Share-based Compensation [Line Items]
Vesting period			3 years
Expiration period			7 years
Equity-classified awards, unrecognized compensation cost	$ 11		$ 11
Weighted average period over which unrecognized cost is recognized, years			1 year 3 months 18 days
Restricted stock
Share-based Compensation [Line Items]
Vesting period			4 years
RSUs
Share-based Compensation [Line Items]
Vesting period	4 years	4 years
Weighted average period over which unrecognized cost is recognized, years			3 years 2 months 12 days
Liability classified awards, unrecognized compensation costs	$ 38		$ 38
Performance units
Share-based Compensation [Line Items]
Vesting period	3 years	3 years	3 years
Weighted average period over which unrecognized cost is recognized, years			2 years 4 months 24 days
Liability classified awards, unrecognized compensation costs	$ 16		$ 16

Stock-Based Compensation (Sch_2

Stock-Based Compensation (Schedule of Equity-Classified Stock-Based Compensation Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation [Abstract]
Equity-classified awards – expensed	$ 2	$ 5	$ 4	$ 9
Equity-classified awards – capitalized	$ 1	$ 1	$ 2	$ 4

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary of Equity-Classified Stock Option Activity) (Details) - Stock options shares in Thousands	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Number of Options
Beginning balance (in shares) | shares	5,178
Granted (in shares) | shares	0
Exercised (in shares) | shares	0
Forfeited or expired (in shares) | shares	(72)
Ending balance (in shares) | shares	5,106
Exercisable (in shares) | shares	4,590
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 17.06
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	0
Forfeited or expired (in dollars per share) | $ / shares	18.58
Ending balance (in dollars per share) | $ / shares	17.04
Exercisable (in dollars per share) | $ / shares	$ 18.12

Stock-Based Compensation (Sum_2

Stock-Based Compensation (Summary of Equity-Classified Restricted Stock Activity) (Details) - Restricted stock shares in Thousands	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	2,717
Granted (in shares) | shares	15
Vested (in shares) | shares	(990)
Forfeited (in shares) | shares	(175)
Ending balance (in shares) | shares	1,567
Weighted Average Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 7.91
Granted (in dollars per share) | $ / shares	4.12
Vested (in dollars per share) | $ / shares	7.37
Forfeited (in dollars per share) | $ / shares	8.37
Ending balance (in dollars per share) | $ / shares	$ 8.17

Stock-Based Compensation (Sum_3

Stock-Based Compensation (Summary of Equity-Classified Performance Units Activity) (Details) - Performance units - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019
Number of Shares
Beginning balance (in shares)			598,000
Granted (in shares)			0
Vested (in shares)			(371,000)
Forfeited (in shares)			(30,000)
Ending balance (in shares)	197,000		197,000
Weighted Average Fair Value
Beginning balance (in dollars per share)			$ 10.01
Granted (in dollars per share)			0
Vested (in dollars per share)			9.73
Forfeited (in dollars per share)			10.47
Ending balance (in dollars per share)	$ 10.47		$ 10.47
Vesting period	3 years	3 years	3 years
Minimum
Number of Shares
Granted (in shares)			0
Maximum
Number of Shares
Granted (in shares)			2

Stock-Based Compensation (Sch_3

Stock-Based Compensation (Schedule of Liability-Classified Stock-Based Compensation Costs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation [Abstract]
Liability-classified stock-based compensation cost – expensed	$ 2	$ 3	$ 7	$ 4
Liability-classified stock-based compensation cost – capitalized	$ 1	$ 3	$ 4	$ 3

Stock-Based Compensation (Sum_4

Stock-Based Compensation (Summary of Liability-Classified Restricted Stock Unit Activity) (Details) - RSUs shares in Thousands	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	8,202
Granted (in shares) | shares	8,659
Vested (in shares) | shares	(2,617)
Forfeited (in shares) | shares	(739)
Ending balance (in shares) | shares	13,505
Weighted Average Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 3.41
Granted (in dollars per share) | $ / shares	4.34
Vested (in dollars per share) | $ / shares	4.09
Forfeited (in dollars per share) | $ / shares	3.13
Ending balance (in dollars per share) | $ / shares	$ 3.16

Stock-Based Compensation (Sum_5

Stock-Based Compensation (Summary of Liability-Classified Performance Unit Activity) (Details) - Performance units shares in Thousands	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	2,803
Granted (in shares) | shares	2,757
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(119)
Ending balance (in shares) | shares	5,441
Weighted Average Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 3.41
Granted (in dollars per share) | $ / shares	4.34
Vested (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	4.65
Ending balance (in dollars per share) | $ / shares	$ 3.16

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total operating revenues	$ 667	$ 816	$ 1,657	$ 1,736
Depreciation, depletion and amortization expense	121	142	233	285
Operating income	22	124	235	379
Interest expense	15	32	29	71
Gain (Loss) on Derivatives	152	(36)	120	(43)
Loss on early extinguishment of debt	0	(8)	0	(8)
Other (loss) income, Net	(6)	3	(5)	2
Provision (benefit) for income taxes	15	0	(411)	0
Assets	6,545	7,042	6,545	7,042	$ 5,797
Capital investments	368	403	693	741
Restructuring charges	2	18	5	18
Cash and cash equivalents	155		155		201
Property, plant and equipment	5,099		5,099		4,656
Unamortized debt expense	22		22		$ 23
Right-of-use asset	103		103
Change in accrued expenditures	39	19	105	52
Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	330	501	823	1,114
E&P
Segment Reporting Information [Line Items]
Total operating revenues	380	527	931	1,170
Depreciation, depletion and amortization expense	118	126	228	243
Operating income	30	97	240	335
Interest expense	15	32	29	71
Gain (Loss) on Derivatives	152	(36)	120	(43)
Loss on early extinguishment of debt		0		0
Other (loss) income, Net	(5)	3	(4)	3
Provision (benefit) for income taxes	15		(411)
Assets	5,945	5,583	5,945	5,583
Capital investments	367	396	692	730
Restructuring charges	2	16	5	16
E&P | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	(9)	(7)	(18)	(13)
Midstream
Segment Reporting Information [Line Items]
Total operating revenues	287	289	726	566
Depreciation, depletion and amortization expense	3	16	5	42
Operating income	(8)	27	(5)	44
Interest expense	0	0	0	0
Gain (Loss) on Derivatives	0	0	0	0
Loss on early extinguishment of debt		0		0
Other (loss) income, Net	0	0	0	(1)
Provision (benefit) for income taxes	0		0
Assets	277	1,228	277	1,228
Capital investments	0	5	0	9
Restructuring charges		2		2
Midstream | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	339	508	841	1,127
Other
Segment Reporting Information [Line Items]
Total operating revenues	0	0	0	0
Depreciation, depletion and amortization expense	0	0	0	0
Operating income	0	0	0	0
Interest expense	0	0	0	0
Gain (Loss) on Derivatives	0	0	0	0
Loss on early extinguishment of debt		(8)		(8)
Other (loss) income, Net	(1)	0	(1)	0
Provision (benefit) for income taxes	0		0
Assets	323	231	323	231
Capital investments	1	2	1	2
Cash and cash equivalents	155	37	155	37
Income tax receivable	68	89	68	89
Property, plant and equipment	50	83	50	83
Unamortized debt expense	10	12	10	12
Non-qualified retirement plan	6	8	6	8
Other assets	3	3	3	3
Right-of-use asset	29		29
Other | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	0	0	0	0
Marketing
Segment Reporting Information [Line Items]
Total operating revenues	287	265	725	518
Marketing | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	339	463	841	1,039
Marketing | Midstream | Intersegment Revenues
Segment Reporting Information [Line Items]
Total operating revenues	$ 339	$ 463	$ 841	1,039
Non-Core Gathering Assets | Midstream
Segment Reporting Information [Line Items]
Impairments				$ 10

New Accounting Pronouncements -

New Accounting Pronouncements - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	$ 103
Lease liability balance	$ 103
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset		$ 105
Lease liability balance		$ 105

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information (Condensed Consolidating Statement of Operations) (Details) - USD ($) $ in Millions	3 Months Ended					6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018		Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Income Statements, Captions [Line Items]
Total operating revenues	$ 667		$ 816			$ 1,657	$ 1,736
Operating expenses	169		193			334	382
General and administrative expenses	40		59			77	114
Loss on sale of operating assets	3		0			3	0
Restructuring charges	2		18			5	18
Depreciation, depletion and amortization	121		142			233	285
Taxes, other than income taxes	17		15			36	38
Total operating costs and expense	645		692			1,422	1,357
Operating Income	22		124			235	379
Interest Expense, Net	15		32			29	71
Gain (Loss) on Derivatives	152		(36)			120	(43)
Gain (Loss) on Early Extinguishment of Debt	0		(8)			0	(8)
Other Income (Loss), Net	(6)		3			(5)	2
Equity in Earnings of Subsidiaries	0		0			0	0
Income (Loss) Before Income Taxes	153		51			321	259
Provision (benefit) for income taxes	15		0			(411)	0
Net Income	138	$ 594	51	[1]	$ 208	732	259	[1]
Participating securities - mandatory convertible preferred stock	0		0			0	2
Net Income Attributable to Common Stock	138		51			732	257
Other comprehensive income	4		0			4	0
Comprehensive income	142	$ 594	51	[1]	$ 208	736	259	[1]
Eliminations
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Operating expenses	0		0			0	0
General and administrative expenses	0		0			0	0
Loss on sale of operating assets	0					0
Restructuring charges	0		0			0	0
Depreciation, depletion and amortization	0		0			0	0
Taxes, other than income taxes	0		0			0	0
Total operating costs and expense	0		0			0	0
Operating Income	0		0			0	0
Interest Expense, Net	0		0			0	0
Gain (Loss) on Derivatives	0		0			0	0
Gain (Loss) on Early Extinguishment of Debt			0				0
Other Income (Loss), Net	0		0			0	0
Equity in Earnings of Subsidiaries	(153)		(91)			(761)	(338)
Income (Loss) Before Income Taxes	(153)		(91)			(761)	(338)
Provision (benefit) for income taxes	0		0			0	0
Net Income	(153)		(91)			(761)	(338)
Participating securities - mandatory convertible preferred stock							0
Net Income Attributable to Common Stock							(338)
Other comprehensive income	0		0			0	0
Comprehensive income	(153)		(91)			(761)	(338)
Parent
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Operating expenses	0		0			0	0
General and administrative expenses	0		0			0	0
Loss on sale of operating assets	0					0
Restructuring charges	0		0			0	0
Depreciation, depletion and amortization	0		0			0	0
Taxes, other than income taxes	0		0			0	0
Total operating costs and expense	0		0			0	0
Operating Income	0		0			0	0
Interest Expense, Net	15		32			29	71
Gain (Loss) on Derivatives	0		0			0	0
Gain (Loss) on Early Extinguishment of Debt			(8)				(8)
Other Income (Loss), Net	0		0			0	0
Equity in Earnings of Subsidiaries	153		91			761	338
Income (Loss) Before Income Taxes	138		51			732	259
Provision (benefit) for income taxes	0		0			0	0
Net Income	138		51			732	259
Participating securities - mandatory convertible preferred stock							2
Net Income Attributable to Common Stock							257
Other comprehensive income	4		0			4	0
Comprehensive income	142		51			736	259
Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	667		816			1,657	1,736
Operating expenses	169		193			334	382
General and administrative expenses	40		59			77	114
Loss on sale of operating assets	3					3
Restructuring charges	2		18			5	18
Depreciation, depletion and amortization	121		142			233	285
Taxes, other than income taxes	17		15			36	38
Total operating costs and expense	645		692			1,422	1,357
Operating Income	22		124			235	379
Interest Expense, Net	0		0			0	0
Gain (Loss) on Derivatives	152		(36)			120	(43)
Gain (Loss) on Early Extinguishment of Debt			0				0
Other Income (Loss), Net	(6)		3			(5)	2
Equity in Earnings of Subsidiaries	0		0			0	0
Income (Loss) Before Income Taxes	168		91			350	338
Provision (benefit) for income taxes	15		0			(411)	0
Net Income	153		91			761	338
Participating securities - mandatory convertible preferred stock							0
Net Income Attributable to Common Stock							338
Other comprehensive income	0		0			0	0
Comprehensive income	153		91			761	338
Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Operating expenses	0		0			0	0
General and administrative expenses	0		0			0	0
Loss on sale of operating assets	0					0
Restructuring charges	0		0			0	0
Depreciation, depletion and amortization	0		0			0	0
Taxes, other than income taxes	0		0			0	0
Total operating costs and expense	0		0			0	0
Operating Income	0		0			0	0
Interest Expense, Net	0		0			0	0
Gain (Loss) on Derivatives	0		0			0	0
Gain (Loss) on Early Extinguishment of Debt			0				0
Other Income (Loss), Net	0		0			0	0
Equity in Earnings of Subsidiaries	0		0			0	0
Income (Loss) Before Income Taxes	0		0			0	0
Provision (benefit) for income taxes	0		0			0	0
Net Income	0		0			0	0
Participating securities - mandatory convertible preferred stock							0
Net Income Attributable to Common Stock							0
Other comprehensive income	0		0			0	0
Comprehensive income	0		0			0	0
Gas sales
Condensed Income Statements, Captions [Line Items]
Total operating revenues	275		407			705	947
Gas sales | Eliminations
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Gas sales | Parent
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Gas sales | Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	275		407			705	947
Gas sales | Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Oil sales
Condensed Income Statements, Captions [Line Items]
Total operating revenues	47		44			86	79
Oil sales | Eliminations
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Oil sales | Parent
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Oil sales | Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	47		44			86	79
Oil sales | Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
NGL sales
Condensed Income Statements, Captions [Line Items]
Total operating revenues	58		75			139	140
NGL sales | Eliminations
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
NGL sales | Parent
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
NGL sales | Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	58		75			139	140
NGL sales | Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Marketing
Condensed Income Statements, Captions [Line Items]
Total operating revenues	287		265			725	518
Marketing | Eliminations
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Marketing | Parent
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Marketing | Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	287		265			725	518
Marketing | Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		0			0	0
Gas gathering
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		24			0	48
Gas gathering | Eliminations
Condensed Income Statements, Captions [Line Items]
Total operating revenues			0				0
Gas gathering | Parent
Condensed Income Statements, Captions [Line Items]
Total operating revenues			0				0
Gas gathering | Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues			24				48
Gas gathering | Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues			0				0
Other
Condensed Income Statements, Captions [Line Items]
Total operating revenues	0		1			2	4
Other | Eliminations
Condensed Income Statements, Captions [Line Items]
Total operating revenues			0			0	0
Other | Parent
Condensed Income Statements, Captions [Line Items]
Total operating revenues			0			0	0
Other | Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues			1			2	4
Other | Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Total operating revenues			0			0	0
Marketing purchases
Condensed Income Statements, Captions [Line Items]
Marketing purchases	293		265			734	520
Marketing purchases | Eliminations
Condensed Income Statements, Captions [Line Items]
Marketing purchases	0		0			0	0
Marketing purchases | Parent
Condensed Income Statements, Captions [Line Items]
Marketing purchases	0		0			0	0
Marketing purchases | Guarantors
Condensed Income Statements, Captions [Line Items]
Marketing purchases	293		265			734	520
Marketing purchases | Non-Guarantors
Condensed Income Statements, Captions [Line Items]
Marketing purchases	$ 0		$ 0			$ 0	$ 0
[1]	In 2018, deferred tax activity incurred in other comprehensive income was offset by a valuation allowance.

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 155		$ 201
Accounts receivable, net	358		581
Other current assets	251		174
Total current assets	764		956
Intercompany receivables	0		0
Natural gas and oil properties, using the full cost method	24,823		24,180
Other	555		525
Less: Accumulated depreciation, depletion and amortization	(20,279)		(20,049)
Total property and equipment, net	5,099		4,656
Investments in subsidiaries (equity method)	0		0
Other long-term assets	682		185
TOTAL ASSETS	6,545		5,797	$ 7,042
Current liabilities:
Accounts payable	585		609
Other current liabilities	327		237
Total current liabilities	912		846
Intercompany payables	0		0
Long-term debt	2,267		2,318
Pension and other postretirement liabilities	39		46
Other long-term liabilities	245		225
Negative carrying amount of subsidiaries, net	0		0
Total long-term liabilities	2,551		2,589
Commitments and contingencies (Note 13)
Total equity	3,082	$ 2,937	2,362	$ 2,250	$ 2,193	$ 1,979
TOTAL LIABILITIES AND EQUITY	6,545		5,797
Eliminations
Current assets:
Cash and cash equivalents	0		0
Accounts receivable, net	0		0
Other current assets	0		0
Total current assets	0		0
Intercompany receivables	(7,894)		(7,932)
Natural gas and oil properties, using the full cost method	0		0
Other	0		0
Less: Accumulated depreciation, depletion and amortization	0		0
Total property and equipment, net	0		0
Investments in subsidiaries (equity method)	(23)		(24)
Other long-term assets	0		0
TOTAL ASSETS	(7,917)		(7,956)
Current liabilities:
Accounts payable	0		0
Other current liabilities	0		0
Total current liabilities	0		0
Intercompany payables	(7,894)		(7,932)
Long-term debt	0		0
Pension and other postretirement liabilities	0		0
Other long-term liabilities	0		0
Negative carrying amount of subsidiaries, net	(2,441)		(3,199)
Total long-term liabilities	(2,441)		(3,199)
Commitments and contingencies (Note 13)
Total equity	2,418		3,175
TOTAL LIABILITIES AND EQUITY	(7,917)		(7,956)
Parent
Current assets:
Cash and cash equivalents	155		201
Accounts receivable, net	0		4
Other current assets	5		8
Total current assets	160		213
Intercompany receivables	7,894		7,932
Natural gas and oil properties, using the full cost method	0		0
Other	196		197
Less: Accumulated depreciation, depletion and amortization	(162)		(154)
Total property and equipment, net	34		43
Investments in subsidiaries (equity method)	0		0
Other long-term assets	45		19
TOTAL ASSETS	8,133		8,207
Current liabilities:
Accounts payable	72		113
Other current liabilities	193		115
Total current liabilities	265		228
Intercompany payables	0		0
Long-term debt	2,267		2,318
Pension and other postretirement liabilities	39		46
Other long-term liabilities	39		54
Negative carrying amount of subsidiaries, net	2,441		3,199
Total long-term liabilities	4,786		5,617
Commitments and contingencies (Note 13)
Total equity	3,082		2,362
TOTAL LIABILITIES AND EQUITY	8,133		8,207
Guarantors
Current assets:
Cash and cash equivalents	0		0
Accounts receivable, net	358		577
Other current assets	246		166
Total current assets	604		743
Intercompany receivables	0		0
Natural gas and oil properties, using the full cost method	24,769		24,128
Other	330		301
Less: Accumulated depreciation, depletion and amortization	(20,059)		(19,840)
Total property and equipment, net	5,040		4,589
Investments in subsidiaries (equity method)	23		24
Other long-term assets	637		166
TOTAL ASSETS	6,304		5,522
Current liabilities:
Accounts payable	513		496
Other current liabilities	134		122
Total current liabilities	647		618
Intercompany payables	7,892		7,932
Long-term debt	0		0
Pension and other postretirement liabilities	0		0
Other long-term liabilities	206		171
Negative carrying amount of subsidiaries, net	0		0
Total long-term liabilities	206		171
Commitments and contingencies (Note 13)
Total equity	(2,441)		(3,199)
TOTAL LIABILITIES AND EQUITY	6,304		5,522
Non-Guarantors
Current assets:
Cash and cash equivalents	0		0
Accounts receivable, net	0		0
Other current assets	0		0
Total current assets	0		0
Intercompany receivables	0		0
Natural gas and oil properties, using the full cost method	54		52
Other	29		27
Less: Accumulated depreciation, depletion and amortization	(58)		(55)
Total property and equipment, net	25		24
Investments in subsidiaries (equity method)	0		0
Other long-term assets	0		0
TOTAL ASSETS	25		24
Current liabilities:
Accounts payable	0		0
Other current liabilities	0		0
Total current liabilities	0		0
Intercompany payables	2		0
Long-term debt	0		0
Pension and other postretirement liabilities	0		0
Other long-term liabilities	0		0
Negative carrying amount of subsidiaries, net	0		0
Total long-term liabilities	0		0
Commitments and contingencies (Note 13)
Total equity	23		24
TOTAL LIABILITIES AND EQUITY	$ 25		$ 24

Condensed Consolidating Finan_5

Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 543	$ 664
Investing activities:
Capital investments	(586)	(684)
Proceeds from sale	26	6
Other		9
Net cash used in investing activities	(560)	(675)
Financing activities:
Intercompany activities	0	0
Change in bank drafts outstanding	(7)	0
Purchase of treasury stock	(21)	0
Cash paid for tax withholding	(1)	(1)
Payments on long-term debt	0	(1,191)
Payments on revolving credit facility	0	(645)
Borrowings under revolving credit facility	0	1,005
Preferred stock dividend	0	(27)
Other		(10)
Net cash used in financing activities	(29)	(868)
Decrease in cash and cash equivalents	(46)	(879)
Cash and cash equivalents at beginning of year	201	916
Cash and cash equivalents at end of period	155	37
Parent
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	1,124	276
Investing activities:
Capital investments	(1)	(6)
Proceeds from sale	0
Other		0
Net cash used in investing activities	(1)	(6)
Financing activities:
Intercompany activities	(1,140)	(287)
Change in bank drafts outstanding	(7)
Purchase of treasury stock	(21)
Cash paid for tax withholding	(1)
Payments on long-term debt		(1,191)
Payments on revolving credit facility		(645)
Borrowings under revolving credit facility		1,005
Preferred stock dividend		(27)
Other		(10)
Net cash used in financing activities	(1,169)	(1,155)
Decrease in cash and cash equivalents	(46)	(885)
Cash and cash equivalents at beginning of year	201	914
Cash and cash equivalents at end of period	155	29
Guarantors
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	179	725
Investing activities:
Capital investments	(584)	(678)
Proceeds from sale	26
Other		9
Net cash used in investing activities	(558)	(669)
Financing activities:
Intercompany activities	379	(50)
Change in bank drafts outstanding	0
Purchase of treasury stock	0
Cash paid for tax withholding	0
Payments on long-term debt		0
Payments on revolving credit facility		0
Borrowings under revolving credit facility		0
Preferred stock dividend		0
Other		0
Net cash used in financing activities	379	(50)
Decrease in cash and cash equivalents	0	6
Cash and cash equivalents at beginning of year	0	2
Cash and cash equivalents at end of period	0	8
Non-Guarantors
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	0
Investing activities:
Capital investments	(1)	0
Proceeds from sale	0
Other		0
Net cash used in investing activities	(1)	0
Financing activities:
Intercompany activities	1	0
Change in bank drafts outstanding	0
Purchase of treasury stock	0
Cash paid for tax withholding	0
Payments on long-term debt		0
Payments on revolving credit facility		0
Borrowings under revolving credit facility		0
Preferred stock dividend		0
Other		0
Net cash used in financing activities	1	0
Decrease in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of year	0	0
Cash and cash equivalents at end of period	0	0
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(760)	(337)
Investing activities:
Capital investments	0	0
Proceeds from sale	0
Other		0
Net cash used in investing activities	0	0
Financing activities:
Intercompany activities	760	337
Change in bank drafts outstanding	0
Purchase of treasury stock	0
Cash paid for tax withholding	0
Payments on long-term debt		0
Payments on revolving credit facility		0
Borrowings under revolving credit facility		0
Preferred stock dividend		0
Other		0
Net cash used in financing activities	760	337
Decrease in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of year	0	0
Cash and cash equivalents at end of period	$ 0	$ 0