Condensed Consolidated Statement Of Changes In Equity - USD ($) shares in Millions, $ in Millions	Total	ExxonMobil Share Of Common Stock [Member]	ExxonMobil Share Of Earnings Reinvested [Member]	ExxonMobil Share Of Accumulated Other Comprehensive Income [Member]	ExxonMobil Share Of Common Stock Held In Treasury [Member]	ExxonMobil Share Of Equity [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2018	$ 198,528	$ 15,258	$ 421,653	$ (19,564)	$ (225,553)	$ 191,794	$ 6,734
Balance (in shares) - issued at Dec. 31, 2018	8,019
Balance (in shares) - in treasury at Dec. 31, 2018	(3,782)
Balance (in shares) - outstanding at Dec. 31, 2018	4,237
Amortization of stock-based awards	$ 389	389				389
Other	39	(8)				(8)	47
Net income (loss) for the period	5,797		5,480			5,480	317
Dividends - common shares (company)			(7,220)			(7,220)
Dividends - common shares (NCI)							(100)
Dividends - common shares (total)	(7,320)
Other comprehensive income (loss)	1,615			1,359		1,359	256
Acquisitions, at cost (company)					$ (421)	(421)
Acquisitions, at cost (NCI)							(166)
Acquisitions, at cost (total)	$ (587)
Acquisitions (in shares)	(6)				(6)
Dispositions	$ 4				$ 4	4
Balance at Jun. 30, 2019	$ 198,465	15,639	419,913	(18,205)	(225,970)	191,377	7,088
Balance (in shares) - issued at Jun. 30, 2019	8,019
Balance (in shares) - in treasury at Jun. 30, 2019	(3,788)
Balance (in shares) - outstanding at Jun. 30, 2019	4,231
Balance at Mar. 31, 2019	$ 198,021	15,476	420,498	(18,782)	(225,970)	191,222	6,799
Balance (in shares) - issued at Mar. 31, 2019	8,019
Balance (in shares) - in treasury at Mar. 31, 2019	(3,788)
Balance (in shares) - outstanding at Mar. 31, 2019	4,231
Amortization of stock-based awards	$ 166	166				166
Other	35	(3)				(3)	38
Net income (loss) for the period	3,391		3,130			3,130	261
Dividends - common shares (company)			(3,715)			(3,715)
Dividends - common shares (NCI)							(57)
Dividends - common shares (total)	(3,772)
Other comprehensive income (loss)	707			577		577	130
Acquisitions, at cost (NCI)							(83)
Acquisitions, at cost (total)	(83)
Balance at Jun. 30, 2019	$ 198,465	15,639	419,913	(18,205)	(225,970)	191,377	7,088
Balance (in shares) - issued at Jun. 30, 2019	8,019
Balance (in shares) - in treasury at Jun. 30, 2019	(3,788)
Balance (in shares) - outstanding at Jun. 30, 2019	4,231
Balance at Dec. 31, 2019	$ 198,938	15,637	421,341	(19,493)	(225,835)	191,650	7,288
Balance (in shares) - issued at Dec. 31, 2019	8,019
Balance (in shares) - in treasury at Dec. 31, 2019	(3,785)
Balance (in shares) - outstanding at Dec. 31, 2019	4,234
Amortization of stock-based awards	$ 358	358				358
Other	197	(183)				(183)	380
Net income (loss) for the period	(1,939)		(1,690)			(1,690)	(249)
Dividends - common shares (company)			(7,434)			(7,434)
Dividends - common shares (NCI)							(93)
Dividends - common shares (total)	(7,527)
Cumulative effect of accounting change	(94)		(93)			(93)	(1)
Other comprehensive income (loss)	(2,416)			(2,124)		(2,124)	(292)
Acquisitions, at cost (company)					$ (305)	(305)
Acquisitions, at cost (NCI)							(63)
Acquisitions, at cost (total)	$ (368)
Acquisitions (in shares)	(6)				(6)
Dispositions	$ 4				$ 4	4
Balance at Jun. 30, 2020	$ 187,153	15,812	412,124	(21,617)	(226,136)	180,183	6,970
Balance (in shares) - issued at Jun. 30, 2020	8,019
Balance (in shares) - in treasury at Jun. 30, 2020	(3,791)
Balance (in shares) - outstanding at Jun. 30, 2020	4,228
Balance at Mar. 31, 2020	$ 188,743	15,636	416,919	(24,339)	(226,137)	182,079	6,664
Balance (in shares) - issued at Mar. 31, 2020	8,019
Balance (in shares) - in treasury at Mar. 31, 2020	(3,791)
Balance (in shares) - outstanding at Mar. 31, 2020	4,228
Amortization of stock-based awards	$ 177	177				177
Other	222	(1)				(1)	223
Net income (loss) for the period	(1,169)		(1,080)			(1,080)	(89)
Dividends - common shares (company)			(3,715)			(3,715)
Dividends - common shares (NCI)							(48)
Dividends - common shares (total)	(3,763)
Other comprehensive income (loss)	2,942			2,722		2,722	220
Dispositions	1				1	1
Balance at Jun. 30, 2020	$ 187,153	$ 15,812	$ 412,124	$ (21,617)	$ (226,136)	$ 180,183	$ 6,970
Balance (in shares) - issued at Jun. 30, 2020	8,019
Balance (in shares) - in treasury at Jun. 30, 2020	(3,791)
Balance (in shares) - outstanding at Jun. 30, 2020	4,228