Dispositions and Other Transactions - Summary of Revenues and Costs from Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Costs and other deductions
Net income of Algeria Assets, after taxes	$ (1,415)	$ 0	$ (1,415)	$ 0
Algeria Africa Assets | Discontinued Operations, Disposed of by Sale
Revenues and other income
Net sales	116		319
Costs and other deductions
Oil and gas lease operating expense	21		44
Transportation expense	7		14
Taxes other than on income	5		48
Depreciation, depletion and amortization	43		110
Impairment upon reclassification to held for use	931		931
Other	4		10
Total costs and other deductions	1,011		1,157
Income before income taxes	(895)		(838)
Income tax expense	(38)		(95)
Net income of Algeria Assets, after taxes	$ (933)		$ (933)