Investments and Advances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Investments and Advances	$ 32,105	$ 29,789
Other at or below cost	392	461
Total investments and advances	32,497	30,250
Equity in Earnings	4,438	2,661	$ 4,684
Investments and Advances | United States
Schedule of Equity Method Investments [Line Items]
Total investments and advances	7,582	7,258
Investments and Advances | International
Schedule of Equity Method Investments [Line Items]
Total investments and advances	24,915	22,992
Equity in Earnings | United States
Schedule of Equity Method Investments [Line Items]
Equity in Earnings	788	802	1,342
Equity in Earnings | International
Schedule of Equity Method Investments [Line Items]
Equity in Earnings	3,650	1,859	3,342
All Other
Schedule of Equity Method Investments [Line Items]
Investments and Advances	(15)	(16)
Equity in Earnings	(1)	(4)	(3)
Upstream | Operating Segments
Schedule of Equity Method Investments [Line Items]
Investments and Advances	20,843	19,153
Equity in Earnings	3,196	1,243	2,218
Upstream | Operating Segments | Tengizchevroil LLP
Schedule of Equity Method Investments [Line Items]
Investments and Advances	13,121	11,414
Equity in Earnings	2,581	1,380	1,939
Upstream | Operating Segments | Petropiar
Schedule of Equity Method Investments [Line Items]
Investments and Advances	1,152	977
Equity in Earnings	175	326	180
Upstream | Operating Segments | Caspian Pipeline Consortium
Schedule of Equity Method Investments [Line Items]
Investments and Advances	1,151	1,245
Equity in Earnings	155	145	162
Upstream | Operating Segments | Petroboscan
Schedule of Equity Method Investments [Line Items]
Investments and Advances	1,080	982
Equity in Earnings	154	(133)	219
Upstream | Operating Segments | Angola LNG Limited
Schedule of Equity Method Investments [Line Items]
Investments and Advances	2,625	2,744
Equity in Earnings	31	(282)	(417)
Upstream | Operating Segments | Other
Schedule of Equity Method Investments [Line Items]
Investments and Advances	1,714	1,791
Equity in Earnings	100	(193)	135
Downstream | Operating Segments
Schedule of Equity Method Investments [Line Items]
Investments and Advances	11,277	10,652
Equity in Earnings	1,243	1,422	2,469
Downstream | Operating Segments | GS Caltex Corporation
Schedule of Equity Method Investments [Line Items]
Investments and Advances	3,826	3,767
Equity in Earnings	290	373	824
Downstream | Operating Segments | Chevron Phillips Chemical Company LLC
Schedule of Equity Method Investments [Line Items]
Investments and Advances	6,200	5,767
Equity in Earnings	723	840	1,367
Downstream | Operating Segments | Caltex Australia Limited
Schedule of Equity Method Investments [Line Items]
Investments and Advances	0	0
Equity in Earnings	0	0	92
Downstream | Operating Segments | Other
Schedule of Equity Method Investments [Line Items]
Investments and Advances	1,251	1,118
Equity in Earnings	$ 230	$ 209	$ 186