Summarized Financial Data - Chevron U.S.A. Inc. (Details 1) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsidiary Statements Captions [Line Items]
Current assets	$ 28,560	$ 29,619
Current liabilities	27,737	31,785
Total CUSA net equity	149,319	146,722	$ 153,886
Chevron U.S.A. Inc.
Subsidiary Statements Captions [Line Items]
Current assets	12,163	11,266
Other assets	54,994	55,722
Current liabilities	17,379	16,660
Other liabilities	12,541	21,701
Total CUSA net equity	37,237	28,627
Memo: Total debt	$ 3,056	$ 9,418