Summarized Financial Data - Chevron U.S.A. Inc. - Income Statement (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales and other operating revenues	$ 29,705	$ 34,189
Costs and other deductions	27,356	31,243
Net income attributable to CUSA	3,599	2,649
Chevron U.S.A. Inc.
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales and other operating revenues	22,039	25,942
Costs and other deductions	21,281	25,757
Net income attributable to CUSA	$ 860	$ 181