Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 756	$ 975	$ 833
Adjustments to reconcile net income to net cash provided by operating activities:
Depletion, depreciation and amortization	1,711	1,534	1,400
Impairment of oil and gas properties	0	77	285
Impairment of inventory and other property and equipment	38	11	2
Exploration expenses, including dry holes	8	27	22
Deferred income taxes	236	274	(519)
(Gain) loss on disposition of assets, net	477	(290)	(208)
Accretion of discount on asset retirement obligations	10	14	19
Interest expense	9	5	5
Derivative related activity	13	(270)	174
Amortization of stock-based compensation	100	85	79
Investment in affiliate valuation adjustment	(15)	0	0
Contingent consideration valuation adjustment	45	0	0
Other	105	658	85
Change in operating assets and liabilities:
Accounts receivable	(227)	(52)	(120)
Inventories	(20)	(70)	(35)
Other assets	(33)	3	(3)
Accounts payable	(7)	321	134
Interest payable	0	(5)	(9)
Other liabilities	(91)	(55)	(45)
Net cash provided by operating activities	3,115	3,242	2,099
Cash flows from investing activities:
Proceeds from disposition of assets, net of cash sold	149	469	352
Proceeds from investments	624	1,373	1,467
Purchase of investments	0	(669)	(904)
Additions to oil and gas properties	(2,988)	(3,520)	(2,365)
Additions to other assets and other property and equipment, net	(232)	(263)	(342)
Net cash used in investing activities	(2,447)	(2,610)	(1,792)
Cash flows from financing activities:
Principal payments on long-term debt	0	(450)	(485)
Payments of other liabilities	(14)	(23)	0
Exercise of long-term incentive plan stock options and employee stock purchases	6	8	6
Purchases of treasury stock	(653)	(179)	(36)
Payments of financing fees	0	(4)	0
Dividends paid	(127)	(55)	(14)
Net cash used in financing activities	(788)	(703)	(529)
Net decrease in cash, cash equivalents and restricted cash	(120)	(71)	(222)
Cash, cash equivalents and restricted cash, beginning of period	825	896	1,118
Cash, cash equivalents and restricted cash, end of period	$ 705	$ 825	$ 896