Investments and Advances - Summary of Financial Information of All Equity Affiliates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Chevron
Schedule of Investments [Line Items]
Total revenues	$ 32,628	$ 40,679	$ 33,460
Income before income tax expense	5,954	6,755	5,712
Net income attributable to affiliates	4,366	6,384	4,468
Current assets	12,998	12,813	13,568
Noncurrent assets	41,531	36,369	32,643
Current liabilities	10,610	9,843	10,201
Noncurrent liabilities	5,068	4,446	4,224
Total affiliates’ net equity	38,851	34,893	31,786
Affiliates
Schedule of Investments [Line Items]
Total revenues	66,473	84,469	70,744
Income before income tax expense	13,197	16,693	13,487
Net income attributable to affiliates	9,809	13,321	10,751
Current assets	30,791	32,657	33,883
Noncurrent assets	97,177	87,614	82,261
Current liabilities	26,032	26,006	26,873
Noncurrent liabilities	21,593	20,000	21,447
Total affiliates’ net equity	$ 80,343	$ 74,265	$ 67,824