Earnings Per Share (Earnings Per Share Computation) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings per common share
Net income attributable to ExxonMobil		$ 3,130	$ 3,950	$ 5,480	$ 8,600
Weighted average number of common shares outstanding		4,271	4,271	4,270	4,270
Earnings per common share (dollars)	[1]	$ 0.73	$ 0.92	$ 1.28	$ 2.01
Dividends paid per common share (dollars)		$ 0.87	$ 0.82	$ 1.69	$ 1.59

[1] The calculation of earnings per common share and earnings per common share – assuming dilution are the same in each period shown.