Description of the Business and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of Business We are a fee-based, growth-oriented master limited partnership formed by Shell to own, operate, develop and acquire pipelines and other midstream assets. Our assets consist of interests in entities that own crude oil and refined products pipelines serving as key infrastructure to transport onshore and offshore crude oil production to Gulf Coast refining markets and to deliver refined products from those markets to major demand centers. As of March 31, 2016, we own interests in four crude oil pipeline systems, two refined products systems and a crude storage terminal. The crude oil pipeline systems, which are held by Zydeco Pipeline Company LLC (“Zydeco”), Mars Oil Pipeline Company (“Mars”), Poseidon Oil Pipeline Company, LLC (“Poseidon”) and the Auger Pipeline System (“Auger”), are strategically located along the Texas and Louisiana Gulf Coast and in the Gulf of Mexico. These systems link major onshore and offshore production areas with key refining markets. The refined products pipeline systems, which are held by Bengal Pipeline Company LLC (“Bengal”) and Colonial Pipeline Company (“Colonial”), connect Gulf Coast and southeastern U.S. refineries to major demand centers from Alabama to New York. The crude storage terminal, called the Lockport Terminal (“Lockport”), is located southwest of Chicago and serves Midwest refineries. Auger and Lockport are owned by our wholly owned subsidiary, Pecten Midstream LLC (“Pecten”). As of March 31, 2016, we own a 100% interest in Pecten, a 62.5% interest in Zydeco, a 28.6% interest in Mars, a 36.0% interest in Poseidon, a 49.0% interest in Bengal and a 3.0% interest in Colonial. Each of Pecten and Zydeco is consolidated within our condensed consolidated financial statements as a subsidiary. The 37.5% ownership interest in Zydeco retained by SPLC is reflected as noncontrolling interest in our condensed consolidated financial statements. We account for each of our investments in Mars, Bengal and Poseidon using the equity method of accounting, and we account for our investment in Colonial using the cost method of accounting. We generate the majority of our revenue under long-term agreements by charging fees for the transportation and storage of crude oil and refined products through our pipelines and storage tanks. Our operations consist of one reportable segment.
Basis of Presentation	Basis of Presentation Our condensed consolidated financial statements include all majority owned and non-majority owned subsidiaries required to be consolidated under generally accepted accounting principles in the United States (“GAAP”). Our reporting currency is U.S. dollars, and all references to dollars are U.S. dollars. The accompanying unaudited condensed consolidated financial statements and related notes have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete annual financial statements. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. During interim periods, we follow the accounting policies disclosed in our Annual Report on Form 10-K for the year ended December 31, 2015 (our “2015 Annual Report”), filed with the United States Securities and Exchange Commission (“SEC”). The unaudited condensed consolidated financial statements for the three months ended March 31, 2016 and 2015 include all adjustments we believe are necessary for a fair statement of the results for the interim periods. These adjustments are of a normal recurring nature unless otherwise disclosed. Operating results for the three months ended March 31, 2016 are not necessarily indicative of the results that may be expected for the full year ended December 31, 2016. These unaudited condensed consolidated financial statements and other information included in this Quarterly Report should be read in conjunction with our consolidated financial statements and notes thereto included in our 2015 Annual Report. The March 31, 2015 condensed consolidated financial statements have been retrospectively adjusted for the acquisition of the Shell Auger and Lockport Operations. These retrospective adjustments include expense allocations for certain functions historically performed by our Parent on behalf of the Shell Auger and Lockport Operations, including allocations of general corporate expenses related to finance, legal, information technology, human resources, communications, ethics and compliance, shared services, employee benefits and incentives, insurance, and share-based compensation. Prior to the contribution of fixed assets and certain agreements on October 1, 2015 related to the Shell Auger and Lockport Operations, the cash generated and used by these operations was deposited to SPLC’s centralized account which was comingled with the cash of other pipeline entities controlled by SPLC. SPLC funded these operating and investing activities as needed. Accordingly, we did not record any cash and cash equivalents held by SPLC on behalf of the Shell Auger and Lockport Operations for any period prior to October 1, 2015. We reflected the cash generated by these operations and expenses paid by SPLC on behalf of these operations as Net distributions to Parent within the accompanying condensed consolidated statements of cash flows.
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The accounting policies are set forth in Note 2 of the Notes to Consolidated Financial Statements in our 2015 Annual Report. There have been no significant changes to these policies during the three months ended March 31, 2016.
Recent Accounting Pronouncements	Recent Accounting Pronouncements For additional information on accounting pronouncements issued prior to March 2016, refer to Note 2 of the Notes to Consolidated Financial Statements in our 2015 Annual Report. In February 2015, the FASB issued an accounting standards update (ASU 2015-02) making targeted changes to the current consolidation guidance. The new standard changes the considerations related to substantive rights, related parties, and decision making fees when applying the variable interest entity consolidation model and eliminates certain guidance for limited partnerships and similar entities under the voting interest consolidation model. The update is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2015. Adoption of this standard did not have a material impact on the consolidated results of operations, financial position or cash flows. In March 2016, the FASB issued accounting standards update (ASU 2016-07) to topic 323, Investments – Equity Method and Joint Ventures, to eliminate the need for an entity to retroactively adopt the equity method of accounting when an investment becomes qualified for the use of the equity method of accounting due to an increase in level of ownership or degree of influence. This provision is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2016. We are currently evaluating the effect of adoption of this guidance on our financial position or results of operations.