Summarized Financial Data - Chevron U.S.A. Inc. (Details 1) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Balance Sheet - Chevron U.S.A. Inc.
Current assets	$ 54,696	$ 55,720
Current liabilities	34,685	34,212
Total Equity	141,486	137,832	126,326	122,181
Chevron U.S.A. Inc. [Member]
Balance Sheet - Chevron U.S.A. Inc.
Current assets	18,881	18,983
Other assets	52,804	52,082
Current liabilities	17,703	18,161
Other liabilities	26,689	26,472
Total Equity	27,293	26,432
Memo: Total debt	$ 14,484	$ 14,482