Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Earnings per common share
Net income attributable to ExxonMobil	$ 32,520		$ 32,580		$ 44,880
Weighted average number of common shares outstanding	4,282		4,419		4,628
Earnings per common share (dollars)	$ 7.6	[1]	$ 7.37	[1]	$ 9.7	[1]
Dividends paid per common share (dollars)	$ 2.7		$ 2.46		$ 2.18

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