Summarized Financial Data - Chevron U.S.A. Inc. (Details 1) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Subsidiary Statements Captions [Line Items]
Current assets	$ 34,256	$ 28,560
Current liabilities	31,862	27,737
Total CUSA net equity	153,380	149,319	$ 147,388	$ 146,722
Chevron U.S.A. Inc.
Subsidiary Statements Captions [Line Items]
Current assets	15,281	12,163
Other assets	55,533	54,994
Current liabilities	17,853	17,379
Other liabilities	13,013	12,541
Total CUSA net equity	39,948	37,237
Memo: Total debt	$ 3,050	$ 3,056