Summarized Financial Data - Chevron U.S.A. Inc. - Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Subsidiary Statements Captions [Line Items]
Current assets	$ 33,087		$ 34,021
Current liabilities	28,829		27,171
Total CUSA net equity	157,451	$ 156,118	155,642	$ 153,380	$ 151,566	$ 149,319
Chevron U.S.A. Inc.
Subsidiary Statements Captions [Line Items]
Current assets	14,241		12,819
Other assets	59,924		55,814
Current liabilities	16,439		16,376
Other liabilities	15,034		12,906
Total CUSA net equity	42,692		39,351
Memo: Total debt	$ 3,189		$ 3,049