Summarized Financial Data - Chevron U.S.A. Inc. - Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Subsidiary Statements Captions [Line Items]
Current assets	$ 23,732		$ 28,329
Current liabilities	20,825		26,530
Total CUSA net equity	134,386	$ 144,914	145,208	$ 157,451	$ 156,118	$ 155,642
Chevron U.S.A. Inc.
Subsidiary Statements Captions [Line Items]
Current assets	8,516		13,059
Other assets	49,972		50,796
Current liabilities	14,884		18,291
Other liabilities	11,392		12,565
Total CUSA net equity	32,212		32,999
Memo: Total debt	$ 3,219		$ 3,222