Income Taxes	6 Months Ended
Jun. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Taxes on income for the second quarter and first six months of 2013 were $3.2 billion and $7.2 billion, respectively, compared with $5.1 billion and $10.7 billion for the corresponding periods in 2012. The associated effective tax rates (calculated as the amount of Income Tax Expense divided by Income Before Income Tax Expense) for the second quarters of 2013 and 2012 were 37 percent and 41 percent, respectively. For the comparative six-month periods, the effective tax rates were 38 percent and 44 percent, respectively. The decrease in the effective tax rate between the quarterly periods was primarily due to lower earnings in higher tax rate international upstream jurisdictions, in addition to the effects of foreign currency remeasurement impacts and non-recurring tax adjustments between periods. The decrease in the effective tax rate for the six-month comparative periods was primarily due to lower earnings in higher tax rate international upstream jurisdictions and foreign currency remeasurement impacts between periods. Tax positions for Chevron and its subsidiaries and affiliates are subject to income tax audits by many tax jurisdictions throughout the world. For the company’s major tax jurisdictions, examinations of tax returns for certain prior tax years had not been completed as of June 30, 2013. For these jurisdictions, the latest years for which income tax examinations had been finalized were as follows: United States — 2007, Nigeria — 2000, Angola — 2001, Saudi Arabia — 2003 and Kazakhstan — 2007. The company engages in ongoing discussions with tax authorities regarding the resolution of tax matters in the various jurisdictions. Both the outcomes for these tax matters and the timing of resolution and/or closure of the tax audits are highly uncertain. However, it is reasonably possible that developments regarding tax matters in certain tax jurisdictions may result in significant increases or decreases in the company’s total unrecognized tax benefits within the next 12 months. Given the number of years that still remain subject to examination and the number of matters being examined in the various tax jurisdictions, the company is unable to estimate the range of possible adjustments to the balance of unrecognized tax benefits. The company is currently assessing the potential impact of an August 2012 decision by the U.S. Court of Appeals for the Third Circuit that disallows the Historic Rehabilitation Tax Credits (HRTCs) claimed by an unrelated taxpayer. The company has claimed a significant amount of HRTCs on its U.S. federal income tax returns in open years, and it is reasonably possible that the specific findings from management's ongoing assessment and evaluation could result in a significant increase in the company's unrecognized tax benefit within the next 12 months. Any such increase would impact the effective tax rate.

Income Taxes

Taxes on income for the second quarter and first six months of 2013 were $3.2 billion and $7.2 billion, respectively, compared with $5.1 billion and $10.7 billion for the corresponding periods in 2012. The associated effective tax rates (calculated as the amount of Income Tax Expense divided by Income Before Income Tax Expense) for the second quarters of 2013 and 2012 were 37 percent and 41 percent, respectively. For the comparative six-month periods, the effective tax rates were 38 percent and 44 percent, respectively.

The decrease in the effective tax rate between the quarterly periods was primarily due to lower earnings in higher tax rate international upstream jurisdictions, in addition to the effects of foreign currency remeasurement impacts and non-recurring tax adjustments between periods. The decrease in the effective tax rate for the six-month comparative periods was primarily due to lower earnings in higher tax rate international upstream jurisdictions and foreign currency remeasurement impacts between periods.

Tax positions for Chevron and its subsidiaries and affiliates are subject to income tax audits by many tax jurisdictions throughout the world. For the company’s major tax jurisdictions, examinations of tax returns for certain prior tax years had not been completed as of June 30, 2013. For these jurisdictions, the latest years for which income tax examinations had been finalized were as follows: United States — 2007, Nigeria — 2000, Angola — 2001, Saudi Arabia — 2003 and Kazakhstan — 2007.

The company engages in ongoing discussions with tax authorities regarding the resolution of tax matters in the various jurisdictions. Both the outcomes for these tax matters and the timing of resolution and/or closure of the tax audits are highly uncertain. However, it is reasonably possible that developments regarding tax matters in certain tax jurisdictions may result in significant increases or decreases in the company’s total unrecognized tax benefits within the next 12 months. Given the number of years that still remain subject to examination and the number of matters being examined in the various tax jurisdictions, the company is unable to estimate the range of possible adjustments to the balance of unrecognized tax benefits.

The company is currently assessing the potential impact of an August 2012 decision by the U.S. Court of Appeals for the Third Circuit that disallows the Historic Rehabilitation Tax Credits (HRTCs) claimed by an unrelated taxpayer. The company has claimed a significant amount of HRTCs on its U.S. federal income tax returns in open years, and it is reasonably possible that the specific findings from management's ongoing assessment and evaluation could result in a significant increase in the company's unrecognized tax benefit within the next 12 months. Any such increase would impact the effective tax rate.