Summarized Financial Data - Chevron U.S.A. Inc. - Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Subsidiary Statements Captions [Line Items]
Current assets	$ 30,433	$ 26,078
Current liabilities	27,480	22,183
Total CUSA net equity	132,933	132,726	$ 144,914	$ 145,208
Chevron U.S.A. Inc.
Subsidiary Statements Captions [Line Items]
Current assets	17,492	10,555
Other assets	47,554	48,054
Current liabilities	18,961	12,403
Other liabilities	21,538	14,102
Total CUSA net equity	24,547	32,104
Memo: Total debt	$ 14,831	$ 7,133