Basis of Presentation and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation General As used in this report, the terms “Valero,” “we,” “us,” or “our” refer to Valero Energy Corporation, one or more of its consolidated subsidiaries, or all of them taken as a whole. These unaudited financial statements have been prepared in accordance with United States (U.S.) generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities Exchange Act of 1934. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation have been included. All such adjustments are of a normal recurring nature unless disclosed otherwise. Operating results for the three months ended March 31, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. The balance sheet as of December 31, 2017 has been derived from our audited financial statements as of that date. For further information, refer to our financial statements and notes thereto included in our annual report on Form 10-K for the year ended December 31, 2017.
Reclassifications	Reclassifications Certain amounts reported for the three months ended March 31, 2017 have been reclassified in order to conform to the 2018 presentation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires us to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. On an ongoing basis, we review our estimates based on currently available information. Changes in facts and circumstances may result in revised estimates.
Revenue Recognition	Revenue Recognition We adopted the provisions of Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers,” (Topic 606) on January 1, 2018, as described below in “Accounting Pronouncements Adopted On January 1, 2018.” Accordingly, our revenue recognition accounting policy has been revised to reflect the adoption of this standard. Our revenues are primarily generated from contracts with customers. We generate revenue from contracts with customers from the sale of products by our refining and ethanol segments. Our VLP segment generates intersegment revenues from transportation and terminaling activities provided to our refining segment that are eliminated in consolidation. Revenues are recognized when we satisfy our performance obligation to transfer products to our customers, which typically occurs at a point in time upon shipment or delivery of the products, and for an amount that reflects the transaction price that is allocated to the performance obligation. The customer is able to direct the use of, and obtain substantially all of the benefits from, the products at the point of shipment or delivery. As a result, we consider control to have transferred upon shipment or delivery because we have a present right to payment at that time, the customer has legal title to the asset, we have transferred physical possession of the asset, and the customer has significant risks and rewards of ownership of the asset. Our contracts with customers state the final terms of the sale, including the description, quantity, and price for goods sold. Payment is typically due in full within two to ten days of delivery. In the normal course of business, we generally do not accept product returns. The transaction price is the consideration that we expect to be entitled to in exchange for our products. The transaction price for substantially all of our contracts is generally based on commodity market pricing (i.e., variable consideration). As such, this market pricing may be constrained (i.e., not estimable) at the inception of the contract but will be recognized based on the applicable market pricing, which will be known upon transfer of the goods to the customer. Some of our contracts also contain variable consideration in the form of sales incentives to our customers, such as discounts and rebates. For contracts that include variable consideration, we estimate the factors that determine the variable consideration in order to establish the transaction price. We have elected to exclude from the measurement of the transaction price all taxes assessed by governmental authorities that are both imposed on and concurrent with a specific revenue-producing transaction and collected by us from a customer (e.g., sales tax, use tax, value-added tax, etc.). We continue to include in the transaction price excise taxes that are imposed on certain inventories in our international operations. The amount of such taxes is provided in supplemental information in a footnote on the statements of income. There are instances where we provide shipping services in relation to the goods sold to our customer. Shipping and handling costs that occur before the customer obtains control of the goods are deemed to be fulfillment activities and are included in cost of materials and other. We have elected to account for shipping and handling activities that occur after the customer has obtained control of a good as fulfillment activities rather than as a promised service and we have included these activities in cost of materials and other.
New Accounting Pronouncements	Accounting Pronouncements Adopted On January 1, 2018 Topic 606 Effective January 1, 2018, we adopted the provisions of Topic 606, which clarifies the principles for recognizing revenue and supersedes previous revenue recognition requirements under “Revenue Recognition (Topic 605),” using the modified retrospective method of adoption as permitted by the standard. Under this method, the cumulative effect of initially applying the standard is recognized as an adjustment to the opening balance of retained earnings, and revenues reported in the periods prior to the date of adoption are not changed. We elected to apply the transition guidance only to contracts that were not completed as of the date of adoption. There was no material impact to our financial position as a result of adopting Topic 606; therefore, there was no cumulative-effect adjustment to retained earnings as of January 1, 2018. Additionally, there was no material impact to our financial position or results of operations as of and for the three months ended March 31, 2018. See “Revenue Recognition” above for a discussion of our accounting policy affected by our adoption of Topic 606. Also see Note 10 for further information on our revenues. We implemented new processes in order to monitor ongoing compliance with accounting and disclosure requirements. ASU No. 2016-01 In January 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-01, “Financial Instruments—Overall (Subtopic 825-10),” (ASU No. 2016-01) to enhance the reporting model for financial instruments regarding certain aspects of recognition, measurement, presentation, and disclosure. Effective January 1, 2018, we adopted the provisions of ASU No. 2016-01 using the cumulative-effect method of adoption as required by the ASU. The adoption of this ASU did not affect our financial position or our results of operations as of or for the three months ended March 31, 2018, but it resulted in reduced disclosures as it eliminated the requirement to disclose the methods and significant assumptions used to estimate the fair value of financial instruments. ASU No. 2017-07 In March 2017, the FASB issued ASU No. 2017-07, “Compensation—Retirement Benefits (Topic 715),” (ASU No. 2017-07) which requires employers to report the service cost component of net periodic pension cost and net periodic postretirement benefit cost in the same line item as other compensation costs arising from services rendered by the pertinent employees during the period. It also requires the other components of net periodic pension cost and net periodic postretirement benefit cost (non-service cost components) to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. Effective January 1, 2018, we retrospectively adopted the provisions of ASU No. 2017-07. The adoption of this ASU did not affect our financial position or results of operations. However, for the three months ended March 31, 2017, we reclassified the non-service cost components out of operating expenses (excluding depreciation and amortization expense) and general and administrative expenses (excluding depreciation and amortization expense) of $7 million and $2 million, respectively, and into other income, net. ASU No. 2017-09 In May 2017, the FASB issued ASU No. 2017-09, “Compensation—Stock Compensation (Topic 718),” (ASU No. 2017-09) to reduce diversity in practice, as well as reduce cost and complexity regarding a change to the terms or conditions of a share-based payment award. Effective January 1, 2018, we adopted ASU No. 2017-09. The adoption of this ASU did not have an immediate effect on our financial position or results of operations as it is applied prospectively to an award modified on or after adoption. ASU No. 2018-02 In February 2018, the FASB issued ASU No. 2018-02, “Income Statement—Reporting Comprehensive Income (Topic 220),” (ASU No. 2018-02) which allows for the stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 (Tax Reform) to be reclassified from accumulated other comprehensive income to retained earnings. The provisions of ASU No. 2018-02 are effective for annual reporting periods beginning after December 15, 2018, and interim reporting periods within those annual periods, with early adoption permitted. This ASU shall be applied either at the beginning of the annual or interim period of adoption or retrospectively to each period in which the income tax effects of Tax Reform affects the items remaining in accumulated other comprehensive income (loss). We elected to reclassify the stranded income tax effects of Tax Reform from accumulated other comprehensive loss to retained earnings as of the beginning of the interim period of adoption. Effective January 1, 2018, we adopted ASU No. 2018-02 and such adoption did not affect our financial position or results of operations but resulted in the reclassification of $91 million of income tax benefits related to Tax Reform from accumulated other comprehensive loss to retained earnings as presented in Note 5 under “Accumulated Other Comprehensive Loss.” We release stranded income tax effects from accumulated other comprehensive income (loss) to retained earnings on an individual item basis as those items are reclassified into income. ASU No. 2018-05 In March 2018, the FASB issued ASU No. 2018-05, “Income Taxes (Topic 740)—Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118,” (ASU No. 2018-05) which amends certain Securities and Exchange Commission (SEC) material in Topic 740 for the income tax accounting implications of the recently issued Tax Reform. This guidance clarifies the application of Topic 740 in situations where a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete the accounting under Topic 740 for certain income tax effects of Tax Reform for the reporting period in which Tax Reform was enacted. See Note 8 for a discussion of the impacts of this ASU. Accounting Pronouncements Not Yet Adopted Topic 842 In February 2016, the FASB issued “Leases (Topic 842),” (Topic 842) to increase the transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. This new standard is effective for annual reporting periods beginning after December 15, 2018, and interim reporting periods within those annual periods, with early adoption permitted. We will adopt this new standard on January 1, 2019, and we expect to use the modified retrospective method of adoption. We are enhancing our contracting and lease evaluation systems and related processes, and we are developing a new lease accounting system to capture our leases and support the required disclosures. During 2018, we will continue to monitor the adoption process to ensure compliance with accounting and disclosure requirements. We also continue the integration of our lease accounting system with our general ledger, and we will make modifications to the related procurement and payment processes. We anticipate this standard will have a material impact on our financial position by increasing our assets and liabilities by equal amounts through the recognition of right-of-use assets and lease liabilities for our operating leases. However, we do not expect adoption to have a material impact on our results of operations or liquidity. We expect our accounting for capital leases to remain substantially unchanged. ASU No. 2017-12 In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging (Topic 815),” (ASU No. 2017-12) to improve and simplify accounting guidance for hedge accounting. The provisions of this ASU are effective for annual reporting periods beginning after December 15, 2018, and interim reporting periods within those annual periods, with early adoption permitted. We use economic hedges to manage commodity price risk; however, we have not designated these hedges as fair value or cash flow hedges. As a result, the adoption of ASU No. 2017-12 effective January 1, 2019 is not expected to affect our financial position or results of operations.
Variable interest entities	In the normal course of business, we have financial interests in certain entities that have been determined to be VIEs. We hold variable interests in VIEs that have not been consolidated because we are not considered the primary beneficiary. These non-consolidated VIEs are not material to our financial position or results of operations and are primarily accounted for as equity investments. MVP is one of our non-consolidated VIEs and is accounted for under owner accounting as described in Note 4.
Offsetting fair value amounts of commodity derivative contracts	We have elected to offset the fair value amounts recognized for multiple similar derivative contracts executed with the same counterparty, including any related cash collateral assets or obligations as shown below; however, fair value amounts by hierarchy level are presented in the following tables on a gross basis. We have no derivative contracts that are subject to master netting arrangements that are reflected gross on the balance sheet.
Derivatives	We are exposed to market risks primarily related to the volatility in the price of commodities, and foreign currency exchange rates, and the price of credits needed to comply with various government and regulatory programs. We enter into derivative instruments to manage some of these risks, including derivative instruments related to the various commodities we purchase or produce, and foreign currency exchange and purchase contracts, as described below under “Risk Management Activities by Type of Risk.” These derivative instruments are recorded as either assets or liabilities measured at their fair values (see Note 12), as summarized below under “Fair Values of Derivative Instruments,” with changes in fair value recognized currently in income. The effect of these derivative instruments on our income is summarized below under “Effect of Derivative Instruments on Income.”
Derivative instruments collateral requirements	We do not require any collateral or other security to support derivative instruments into which we enter.