Summarized Financial Data - Chevron U.S.A. Inc. - Income Statement (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales and other operating revenues	$ 23,997	$ 34,779	$ 69,628	$ 105,291
Costs and other deductions	24,495	32,067	75,942	96,225
Net income attributable to equity method investee	$ (207)	$ 2,580	(4,878)	9,534
Chevron U.S.A. Inc.
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales and other operating revenues			50,360	82,073
Costs and other deductions			54,221	79,794
Net income attributable to equity method investee			$ (2,203)	$ 2,149