Equity Company Information (Schedule Of Equity Company Financial Summary) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Investments (Companies carried at equity in underlying assets)	$ 26,382	$ 24,354	$ 20,810
Total Equity Company Including All Owners [Member]
Schedule of Equity Method Investments [Line Items]
Total revenues	112,938	94,791	80,247
Income before income taxes	37,203	29,748	22,269
Income taxes	11,568	8,421	6,334
Income from equity affiliates	25,635	21,327	15,935
Current assets	38,670	35,367	34,412
Long-term assets	128,830	122,221	109,646
Total assets	167,500	157,588	144,058
Current liabilities	27,324	21,725	20,507
Long-term liabilities	56,913	59,736	62,110
Investments (Companies carried at equity in underlying assets)	83,263	76,127	61,441
Exxon Mobil Corporation Share After Noncontrolling Interest [Member]
Schedule of Equity Method Investments [Line Items]
Total revenues	34,539	29,340	24,668
Income before income taxes	10,482	8,498	6,509
Income taxes	3,151	2,236	1,701
Income from equity affiliates	7,331	6,262	4,808
Current assets	13,394	12,050	11,392
Long-term assets	35,970	34,931	32,357
Total assets	49,364	46,981	43,749
Current liabilities	7,606	6,348	5,765
Long-term liabilities	17,109	17,056	17,288
Investments (Companies carried at equity in underlying assets)	$ 24,649	$ 23,577	$ 20,696