Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ (170)	$ 412
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depletion, depreciation and amortization	1,243	1,271
Impairment of inventory and other property and equipment	2	34
Exploration expenses, including dry holes	8	6
Deferred income taxes	(8)	127
(Gain) loss on disposition of assets, net	(7)	477
Loss on early extinguishment of debt	27	0
Accretion of discount on asset retirement obligations	7	7
Interest expense	34	4
Derivative-related activity	28	(116)
Amortization of stock-based compensation	54	81
Investment in affiliate valuation adjustment	119	22
South Texas contingent consideration valuation adjustment	42	61
South Texas deficiency fee obligation	69	0
Other	94	96
Change in operating assets and liabilities:
Accounts receivable	371	(47)
Inventories	13	(55)
Other assets	22	(15)
Accounts payable	(164)	1
Interest payable	(37)	(29)
Other liabilities	(201)	(50)
Net cash provided by operating activities	1,546	2,287
Cash flows from investing activities:
Proceeds from disposition of assets	58	82
Proceeds from investments	0	568
Purchase of investments	(1)	0
Additions to oil and gas properties	(1,297)	(2,380)
Additions to other assets and other property and equipment	(102)	(184)
Net cash used in investing activities	(1,342)	(1,914)
Cash flows from financing activities:
Proceeds from issuance of senior notes, net of discount	1,091	0
Proceeds from issuance of convertible senior notes	1,323	0
Purchase of derivatives related to issuance of convertible senior notes	(113)	0
Borrowing under credit facility	800	0
Repayment of credit facility	(800)	0
Repayment of senior notes, including tender offer premiums	(1,198)	0
Payments of other liabilities	(162)	(10)
Payments of financing fees, net	(36)	0
Purchases of treasury stock	(174)	(627)
Exercise of long-term incentive plan stock options and employee stock purchases	6	6
Dividends paid	(255)	(54)
Net cash provided by (used in) financing activities	482	(685)
Net increase (decrease) in cash, cash equivalents and restricted cash	686	(312)
Cash, cash equivalents and restricted cash, beginning of period	705	825
Cash, cash equivalents and restricted cash, end of period	$ 1,391	$ 513