Employee Benefit Plans (Details Textual) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Maximum annual increase percentage to company contribution for retiree medical coverage	4.00%
Funded Status:
Amounts recognized on a before-tax bases in "Accumulated other comprehensive loss" for the company's pension and other postretirement benefit plans	$ 5,286	$ 5,511
Net Actuarial Loss:
The percentage of the higher of the projected benefit obligation or market-related value of plan assets in excess of which net actuarial losses are amortized	10.00%
Other Benefit Assumptions:
Assumed health care cost-trend rates in the next fiscal year	7.40%	6.90%
Ultimate trend rate for health care cost	4.50%	4.50%
Year when the ultimate health care cost trend rate is expected to be reached	2025	2025
Maximum annual increase in contribution rate in post retirement benefit	4.00%
Primary Investment:
Company's US and UK pension plans as a percentage of total pension assets	90.00%
Benefit Plan Trusts:
Number of Chevron treasury stocks held in benefit plan trust for funding obligations	14.2
Various grantor trust assets invested primarily in interest earning accounts	$ 35	$ 35
Employee Incentive Plan
Charges to expense for cash bonuses	936	662	$ 690
Other Benefits
Funded Status:
Amounts recognized on a before-tax bases in "Accumulated other comprehensive loss" for the company's pension and other postretirement benefit plans	$ (80)	$ (397)
Net Actuarial Loss:
Number of years net actuarial losses recorded in "Accumulated other comprehensive loss" at December 31 for the company's OPEB plans are being amortized for, over a straight-line basis	15 years
Actuarial gain (loss) that will be amortized from Accumulated other comprehensive loss	$ 15
Weighted average amortization period (in years) for recognizing prior service costs (credits) recorded in "Accumulated other comprehensive loss" at December 31 for other postretirement benefit plan	9 years
Amortization of prior service (credits) costs during the next year	$ (28)
Discount Rate:
Discount rate for pension plans	3.80%	4.30%	4.60%
Cash Contributions and Benefit Payments:
Contributions to employee pension plans	$ 151	$ 189
Estimated contributions to employee pension plans for the next fiscal year	174
ESIP
Employee Savings Investment Plan:
Compensation expense	316	281	$ 316
U.S.
Cash Contributions and Benefit Payments:
Contributions to employee pension plans	728
Estimated contributions to employee pension plans for the next fiscal year	700
U.S. | Pension Benefits
Funded Status:
Amounts recognized on a before-tax bases in "Accumulated other comprehensive loss" for the company's pension and other postretirement benefit plans	4,267	4,657
Accumulated benefit obligations pension plans	$ 12,194	$ 11,954
Net Actuarial Loss:
Number of years net actuarial losses recorded in "Accumulated other comprehensive loss" at December 31 for the company's US pension plans are being amortized for, over a straight-line basis	10 years
Actuarial gain (loss) that will be amortized from Accumulated other comprehensive loss	$ 303
Company's estimated amount that will be recognized from "Accumulated other comprehensive loss" during the next year related to lump-sum settlement costs from U.S. pension plans	$ 334
Weighted average amortization period (in years) for recognizing prior service costs (credits) recorded in "Accumulated other comprehensive loss" at December 31 for US pension plan	5 years
Amortization of prior service (credits) costs during the next year	$ 2
Expected Return on Plan Assets:
Estimated long-term rate of return on US pension plan assets	6.75%	7.25%	7.50%
Percentage of US pension plan assets relative to total pension plan assets	68.00%
Plan asset market valuation period, prior to year-end measurement date	3 months
Discount Rate:
Discount rate for pension plans	3.50%	3.90%	4.00%
Cash Contributions and Benefit Payments:
Contributions to employee pension plans	$ 728	$ 406
U.S. | Pension Benefits | Equities | Minimum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	30.00%
U.S. | Pension Benefits | Equities | Maximum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	60.00%
U.S. | Pension Benefits | Fixed Income and Cash | Minimum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	20.00%
U.S. | Pension Benefits | Fixed Income and Cash | Maximum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	65.00%
U.S. | Pension Benefits | Real Estate | Minimum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	0.00%
U.S. | Pension Benefits | Real Estate | Maximum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	15.00%
U.S. | Pension Benefits | Other | Minimum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	0.00%
U.S. | Pension Benefits | Other | Maximum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	15.00%
U.S. | Other Benefits
Discount Rate:
Discount rate for pension plans	3.60%	4.10%	4.50%
Int’l.
Cash Contributions and Benefit Payments:
Estimated contributions to employee pension plans for the next fiscal year	$ 250
Int’l. | Including Portion Funded by Third Party
Cash Contributions and Benefit Payments:
Contributions to employee pension plans	252
Int’l. | Pension Benefits
Funded Status:
Amounts recognized on a before-tax bases in "Accumulated other comprehensive loss" for the company's pension and other postretirement benefit plans	1,099	$ 1,251
Accumulated benefit obligations pension plans	$ 5,009	$ 4,676
Net Actuarial Loss:
Number of years net actuarial losses recorded in "Accumulated other comprehensive loss" at December 31 for the company's international pension plans are being amortized for, over a straight-line basis	12 years
Actuarial gain (loss) that will be amortized from Accumulated other comprehensive loss	$ 30
Weighted average amortization period (in years) for recognizing prior service costs (credits) recorded in "Accumulated other comprehensive loss" at December 31 for international pension plan	9 years
Amortization of prior service (credits) costs during the next year	$ 11
Expected Return on Plan Assets:
Estimated long-term rate of return on US pension plan assets	5.50%	6.30%	6.30%
Discount Rate:
Discount rate for pension plans	3.90%	4.30%	5.30%
Cash Contributions and Benefit Payments:
Contributions to employee pension plans	$ 252	$ 464
Int’l. | Pension Benefits | Equities | UNITED KINGDOM | Minimum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	30.00%
Int’l. | Pension Benefits | Equities | UNITED KINGDOM | Maximum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	50.00%
Int’l. | Pension Benefits | Fixed Income and Cash | UNITED KINGDOM | Minimum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	35.00%
Int’l. | Pension Benefits | Fixed Income and Cash | UNITED KINGDOM | Maximum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	70.00%
Int’l. | Pension Benefits | Real Estate | UNITED KINGDOM | Minimum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	5.00%
Int’l. | Pension Benefits | Real Estate | UNITED KINGDOM | Maximum
Primary Investment:
Pension Plan - Board of Trustees approved asset allocation	15.00%