Description of Business, Basis of Presentation, and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation General These unaudited financial statements have been prepared in accordance with 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, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017. The balance sheet as of December 31, 2016 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, 2016. Acquisitions from Valero The acquisitions from Valero noted above were accounted for as transfers of businesses between entities under the common control of Valero. Accordingly, we recorded these acquisitions on our balance sheet at Valero’s carrying value as of the beginning of the period of transfer, and we retrospectively adjusted prior period financial statements and financial information to furnish comparative information. We refer to the historical results of the transferred assets from Valero prior to their transfer to us as those of our “Predecessor.” The combined financial statements of our Predecessor were derived from the consolidated financial statements and accounting records of Valero and reflect the combined historical financial position, results of operations, and cash flows of our Predecessor as if the acquisitions from Valero had been combined for periods prior to the effective dates of each acquisition. There were no transactions between the operations of our Predecessor; therefore, there were no intercompany transactions or accounts to be eliminated in connection with the combination of those operations. In addition, our Predecessor’s statements of income include direct charges for the management and operation of our assets and certain expenses allocated by Valero for general corporate services, such as treasury, accounting, and legal services. These expenses were charged, or allocated, to our Predecessor based on the nature of the expenses. Prior to the acquisitions from Valero, our Predecessor transferred cash to Valero daily and Valero funded our Predecessor’s operating and investing activities as needed. Therefore, transfers of cash to and from Valero’s cash management system are reflected as a component of net investment and are reflected as a financing activity in our statements of cash flows. In addition, interest expense was not included on the net cash transfers from Valero. The financial information presented for the periods after the effective dates of each acquisition represents the consolidated financial position, results of operations, and cash flows of the Partnership.
Reclassifications	Reclassifications Certain amounts reported as of December 31, 2016 have been reclassified to conform to the 2017 presentation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates. On an ongoing basis, we review our estimates based on currently available information. Changes in facts and circumstances may result in revised estimates.
New Accounting Pronouncements	Accounting Pronouncement Adopted During the Period In January 2017, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2017-01, “Business Combinations (Topic 805),” to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The provisions of this ASU provide a more robust framework to use in determining when a set of assets and activities is a business by clarifying the requirements related to inputs, processes, and outputs. These provisions are to be applied prospectively and are effective for annual reporting periods beginning after December 15, 2017, with early adoption permitted. Our early adoption of this ASU effective January 1, 2017 did not have an effect on our financial position or results of operations. However, more of our future acquisitions may be accounted for as asset acquisitions. Accounting Pronouncements Not Yet Adopted In May 2014, the FASB issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” to clarify the principles for recognizing revenue. The standard is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual periods. We recently completed our evaluation of the provisions of this ASU and concluded that our adoption of the ASU will not materially change the amount or timing of revenues recognized by us, nor will it materially affect our financial position. As described in our revenue recognition policy, our revenues are generated from the transportation of crude oil and refined petroleum products through our pipelines and terminals. These revenues are based on the volume (barrels) of crude oil and refined petroleum products transported at contracted rates per barrel, and we recognize these revenues upon completion of the transportation service, which is the point when our performance obligation is fulfilled. As also described in our revenue recognition policy, certain of our commercial agreements are considered operating leases under U.S. GAAP. The scope of the new standard does not extend to revenues generated by lease arrangements; therefore, lease revenues generated by us will continue to be accounted for under existing accounting standards and be reflected in a separate revenue line item on our statement of income. We will adopt this ASU effective January 1, 2018, and we expect to use the modified retrospective method of adoption as permitted by the ASU. Under that method, the cumulative effect of initially applying the standard is recognized as an adjustment to the opening balance of partners’ capital, and revenues reported in the periods prior to the date of adoption are not changed. We do not, however, expect to make such an adjustment to partners’ capital. In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments—Overall (Subtopic 825-10),” to enhance the reporting model for financial instruments regarding certain aspects of recognition, measurement, presentation, and disclosure. The provisions of this ASU are effective for annual reporting periods beginning after December 15, 2017, and interim reporting periods within those annual periods. This ASU is to be applied using a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. The adoption of this ASU effective January 1, 2018 will not affect our financial position or results of operations, but will result in revised disclosures. In February 2016, the FASB issued ASU No. 2016-02, “Leases (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. The 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 anticipate adopting the new standard on January 1, 2019. We recently completed our evaluation of the provisions of this standard, and a multi-disciplined implementation team has gained an understanding of the standard’s accounting and disclosure provisions. This team is developing enhanced contracting and lease evaluation processes and information systems to support such processes, as well as new and enhanced accounting systems to account for our leases and support the required disclosures. We continue to evaluate the effect that adopting this standard will have on our financial statements and related disclosures.