Summarized Financial Data - Chevron Phillips Chemical Company LLC (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Summarized Financial Data - Chevron Transport Corporation
Sales and other operating revenues	[1]	$ 33,892	$ 29,159	$ 98,293	$ 80,073
Costs and other deductions		33,547	29,031	96,366	85,647
Net income attributable to TCO		$ 1,952	$ 1,283	$ 6,084	(912)
Chevron Phillips Chemical Company LLC
Affiliate Statements Captions [Line Items]
Equity method investment, ownership percentage		50.00%		50.00%
Percentage of affiliate by summarized financial information		100.00%		100.00%
Summarized Financial Data - Chevron Transport Corporation
Sales and other operating revenues				$ 6,816	6,302
Costs and other deductions				5,732	5,127
Net income attributable to TCO				$ 1,424	$ 1,343

[1] Includes excise, value-added and similar taxes: $1,867, $1,772, $5,315, $5,208