Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Cash Flows From Operating Activities
Net Income (Loss)	$ 2,379	$ (450)	$ 5,452	$ (1,883)
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Depreciation, depletion and amortization	1,672	1,411	5,425	3,980
Impairments	(89)	2	(90)	521
Dry hole costs and leasehold impairments			7	114
Accretion on discounted liabilities	61	62	186	195
Deferred taxes			895	(428)
Undistributed equity earnings			258	450
Gain on dispositions	(2)	3	(294)	(551)
(Gain) loss on investment in Cenovus Energy			(743)	1,302
Other			(866)	(188)
Working capital adjustments
Decrease (increase) in accounts and notes receivable			(1,619)	1,132
Increase in inventories			(13)	(74)
Increase in prepaid expenses and other current assets			(800)	(49)
Increase (decrease) in accounts payable			682	(583)
Increase (decrease) in taxes and other accruals			2,648	(808)
Net Cash Provided by Operating Activities			11,128	3,130
Cash Flows From Investing Activities
Cash acquired from Concho			382	0
Capital expenditures and investments			(3,767)	(3,657)
Working capital changes associated with investing activities			79	(229)
Proceeds from asset dispositions			792	1,312
Net sales (purchases) of investments			2,846	(1,089)
Collection of advances/loans-related parties			105	116
Other			(386)	(31)
Net Cash Provided by (Used in) Investing Activities			51	(3,578)
Cash Flows From Financing Activities
Issuance of debt			0	300
Repayment of debt			(363)	(234)
Issuance of company common stock			27	(2)
Repurchase of company common stock			(2,224)	(726)
Dividends paid			(1,750)	(1,367)
Other			6	(27)
Net Cash Used in Financing Activities			(4,304)	(2,056)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash			(3)	(62)
Net Change in Cash, Cash Equivalents and Restricted Cash			6,872	(2,566)
Cash, cash equivalents and restricted cash at beginning of period			3,315	5,362	$ 5,362
Cash, Cash Equivalents and Restricted Cash at End of Period	$ 10,187	$ 2,796	$ 10,187	$ 2,796	$ 3,315