Document And Entity Information	6 Months Ended
	Jun. 30, 2019 shares
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Registrant Name	Exxon Mobil Corp
Entity Central Index Key	0000034088
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	4,231,106,294
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Document Quarterly Report	true
Security 12(b) Title	Common Stock, without par value
Trading Symbol	XOM
Security Exchange Name	NYSE
Entity File Number	1-2256
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	13-5409005
Entity Address, Address Line One	5959 Las Colinas Boulevard
Entity Address City or Town	Irving
Entity Address State or Province	TX
Entity Address, Postal Zip Code	75039-2298
City Area Code	972
Local Phone Number	940-6000
Document Transition Report	false