Description of Business and Basis of Presentation	3 Months Ended
Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation Shell Midstream Partners, L.P. (“we,” “us,” “our” or “the Partnership”) is a Delaware limited partnership formed on March 19, 2014 to own and operate assets, including certain assets received from Shell Pipeline Company LP (“SPLC”). We conduct our operations through our wholly owned subsidiary Shell Midstream Operating, LLC (“Operating Company”). Our general partner is Shell Midstream Partners GP LLC (“general partner”). References to “Shell” or “Parent” refer collectively to Royal Dutch Shell plc (“RDS”) and its controlled affiliates, other than us, our subsidiaries and our general partner. On November 3, 2014, we completed our Initial Public Offering (“IPO”), and our common units trade on the New York Stock Exchange under the symbol “SHLX.” 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 and Midwest refining markets and to deliver refined products from those markets to major demand centers. As of March 31, 2017, we own interests in seven crude oil pipeline systems, three refined products systems, one natural gas gathering pipeline system and a crude tank storage and terminal system. The crude oil pipeline systems include the Auger Pipeline System (“Auger”), held by Pecten Midstream LLC (“Pecten”), Zydeco Pipeline Company LLC (“Zydeco”), Odyssey Pipeline LLC (“Odyssey”), Mars Oil Pipeline Company (“Mars”), Poseidon Oil Pipeline Company LLC (“Poseidon”), Proteus Oil Pipeline Company, LLC (“Proteus”), and Endymion Oil Pipeline Company, LLC (“Endymion”), and 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, and Explorer Pipeline Company (“Explorer”) which serves more than 70 major cities in 16 states from the Gulf Coast to the Midwest. The natural gas pipeline system, Cleopatra Gas Gathering Company, LLC (“Cleopatra”), brings Gulf of Mexico gas production to the market hub at Ship Shoal 332. The crude storage terminal, Lockport Terminal (“Lockport”), is located southwest of Chicago and serves Midwest refineries. As of March 31, 2017, we own a 100% interest in Pecten, a 92.5% interest in Zydeco, a 50.0% interest in Bengal, a 49.0% interest in Odyssey, a 48.6% interest in Mars, a 36.0% interest in Poseidon, a 10.0% interest in Proteus, a 10.0% interest in Endymion, a 6.0% interest in Colonial, a 2.62% interest in Explorer and a 1.0% interest in Cleopatra. Each of Pecten and Zydeco is consolidated within our condensed consolidated financial statements as a subsidiary. The 7.5% 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 Bengal, Odyssey, Mars, Poseidon, Proteus and Endymion using the equity method of accounting, and we account for each of our investments in Colonial, Explorer and Cleopatra using the cost method of accounting. We generate a substantial portion 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 and from income from our equity and cost method investments. Our operations consist of one reportable segment. 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, 2016 (our “2016 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, 2017 and 2016 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, 2017 are not necessarily indicative of the results that may be expected for the full year. These unaudited condensed consolidated financial statements and other information included in this Quarterly Report on Form 10-Q should be read in conjunction with our consolidated financial statements and notes thereto included in our 2016 Annual Report. Summary of Significant Accounting Policies The accounting policies are set forth in Note 2—Summary of Significant Accounting Policies in the Notes to Consolidated Financial Statements of our 2016 Annual Report. There have been no significant changes to these policies during the three months ended March 31, 2017. Recently Adopted Accounting Pronouncements In October 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-17 to Topic 810, Consolidation, making changes on how a reporting entity should treat indirect interests in an entity held through related parties that are under common control with the reporting entity when determining whether it is the primary beneficiary of a variable interest entity. The update was effective for us as of January 1, 2017. The adoption of this update did not have a material impact on our financial statements. In March 2016, the FASB issued 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. The update was effective for us as of January 1, 2017. The adoption of this update did not have a material impact on our financial statements. Recent Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, which will supersede nearly all existing revenue recognition guidance under GAAP. The update's core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The update is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2017. The update allows for either “full retrospective” adoption, meaning the standard is applied to all of the periods presented, or “modified retrospective” adoption, meaning the standard is applied only to the most current period presented in the financial statements. We continue to evaluate our existing revenue recognition policies to determine whether any contracts in the scope of the guidance will be affected by the new requirements. We have not yet selected a transition method nor have we determined the effect of the update on our consolidated results of operations, financial position or cash flows. For additional information on accounting pronouncements issued prior to March 2017, refer to Note 2—Summary of Significant Accounting Policies in the Notes to Consolidated Financial Statements of our 2016 Annual Report.

Description of Business and Basis of Presentation

Shell Midstream Partners, L.P. (“we,” “us,” “our” or “the Partnership”) is a Delaware limited partnership formed on March 19, 2014 to own and operate assets, including certain assets received from Shell Pipeline Company LP (“SPLC”). We conduct our operations through our wholly owned subsidiary Shell Midstream Operating, LLC (“Operating Company”). Our general partner is Shell Midstream Partners GP LLC (“general partner”). References to “Shell” or “Parent” refer collectively to Royal Dutch Shell plc (“RDS”) and its controlled affiliates, other than us, our subsidiaries and our general partner. On November 3, 2014, we completed our Initial Public Offering (“IPO”), and our common units trade on the New York Stock Exchange under the symbol “SHLX.”

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 and Midwest refining markets and to deliver refined products from those markets to major demand centers. As of March 31, 2017, we own interests in seven crude oil pipeline systems, three refined products systems, one natural gas gathering pipeline system and a crude tank storage and terminal system. The crude oil pipeline systems include the Auger Pipeline System (“Auger”), held by Pecten Midstream LLC (“Pecten”), Zydeco Pipeline Company LLC (“Zydeco”), Odyssey Pipeline LLC (“Odyssey”), Mars Oil Pipeline Company (“Mars”), Poseidon Oil Pipeline Company LLC (“Poseidon”), Proteus Oil Pipeline Company, LLC (“Proteus”), and Endymion Oil Pipeline Company, LLC (“Endymion”), and 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, and Explorer Pipeline Company (“Explorer”) which serves more than 70 major cities in 16 states from the Gulf Coast to the Midwest. The natural gas pipeline system, Cleopatra Gas Gathering Company, LLC (“Cleopatra”), brings Gulf of Mexico gas production to the market hub at Ship Shoal 332. The crude storage terminal, Lockport Terminal (“Lockport”), is located southwest of Chicago and serves Midwest refineries.

As of March 31, 2017, we own a 100% interest in Pecten, a 92.5% interest in Zydeco, a 50.0% interest in Bengal, a 49.0% interest in Odyssey, a 48.6% interest in Mars, a 36.0% interest in Poseidon, a 10.0% interest in Proteus, a 10.0% interest in Endymion, a 6.0% interest in Colonial, a 2.62% interest in Explorer and a 1.0% interest in Cleopatra. Each of Pecten and Zydeco is consolidated within our condensed consolidated financial statements as a subsidiary. The 7.5% 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 Bengal, Odyssey, Mars, Poseidon, Proteus and Endymion using the equity method of accounting, and we account for each of our investments in Colonial, Explorer and Cleopatra using the cost method of accounting.

We generate a substantial portion 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 and from income from our equity and cost method investments. Our operations consist of one reportable segment.

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, 2016 (our “2016 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, 2017 and 2016 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, 2017 are not necessarily indicative of the results that may be expected for the full year. These unaudited condensed consolidated financial statements and other information included in this Quarterly Report on Form 10-Q should be read in conjunction with our consolidated financial statements and notes thereto included in our 2016 Annual Report.

Summary of Significant Accounting Policies

The accounting policies are set forth in Note 2—Summary of Significant Accounting Policies in the Notes to Consolidated Financial Statements of our 2016 Annual Report. There have been no significant changes to these policies during the three months ended March 31, 2017.

Recently Adopted Accounting Pronouncements

In October 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-17 to Topic 810, Consolidation, making changes on how a reporting entity should treat indirect interests in an entity held through related parties that are under common control with the reporting entity when determining whether it is the primary beneficiary of a variable interest entity. The update was effective for us as of January 1, 2017. The adoption of this update did not have a material impact on our financial statements.

In March 2016, the FASB issued 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. The update was effective for us as of January 1, 2017. The adoption of this update did not have a material impact on our financial statements.

Recent Accounting Pronouncements

In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, which will supersede nearly all existing revenue recognition guidance under GAAP. The update's core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The update is effective for fiscal years and interim periods within those fiscal years beginning after December 15, 2017. The update allows for either “full retrospective” adoption, meaning the standard is applied to all of the periods presented, or “modified retrospective” adoption, meaning the standard is applied only to the most current period presented in the financial statements. We continue to evaluate our existing revenue recognition policies to determine whether any contracts in the scope of the guidance will be affected by the new requirements. We have not yet selected a transition method nor have we determined the effect of the update on our consolidated results of operations, financial position or cash flows.

For additional information on accounting pronouncements issued prior to March 2017, refer to Note 2—Summary of Significant Accounting Policies in the Notes to Consolidated Financial Statements of our 2016 Annual Report.