Asset Acquisitions, Dispositions and Other (Detail 2) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 31, 2015	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Acquisitions, dispositions and other transactions
Impairment charges			$ 3,100
Sales and other operating revenues and income from discontinued operations related to California Resources Company
Income from discontinued operations			$ (3)	$ 213	$ (10)	$ 741
Subsequent event | Westwood Building
Acquisitions, dispositions and other transactions
Proceeds from sale of building	$ 65
Williston Operations
Acquisitions, dispositions and other transactions
Impairment charges		$ 763
California Resources Corporation | Spin-off California Resources Corp
Sales and other operating revenues and income from discontinued operations related to California Resources Company
Sales and other operating revenue from discontinued operations				1,092		3,353
Income from discontinued operations before-tax				334		1,146
Income tax expense				(118)		(404)
Income from discontinued operations				$ 216		$ 742