Summarized Financial Data - Chevron U.S.A. Inc. (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Statement of Income - Chevron U.S.A. Inc.
Sales and other operating revenues	$ 32,315	[1]	$ 50,978	[1]
Costs and other deductions	31,653		45,337
Net income attributable to CUSA	2,567		4,512
Chevron U.S.A. Inc. [Member]
Statement of Income - Chevron U.S.A. Inc.
Sales and other operating revenues	24,283		41,329
Costs and other deductions	24,455		40,124
Net income attributable to CUSA	$ 162		$ 1,017

[1] * Includes excise, value-added and similar taxes:$1,877 $1,946