Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2017
Accounting Policies [Abstract]
Motor Fuel and Sales Taxes	Motor Fuel and Sales Taxes Certain motor fuel and sales taxes are collected from customers and remitted to governmental agencies either directly by the Partnership or through suppliers. The Partnership’s accounting policy for wholesale direct sales to dealer and commercial customers is to exclude the collected motor fuel tax from sales and cost of sales. For retail locations where the Partnership holds inventory, including consignment arrangements, motor fuel sales and motor fuel cost of sales include motor fuel taxes. Such amounts were $15 million and $15 million for the three months ended June 30, 2017 and 2016, respectively, and $30 million and $30 million for the six months ended June 30, 2017 and 2016, respectively. Merchandise sales and cost of merchandise sales are reported net of sales tax in the accompanying Consolidated Statements of Operations and Comprehensive Income.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements FASB ASU No. 2014-09. In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") No. 2014-09, "Revenue from Contracts with Customers (Topic 606)" (“ASU 2014-09”), which clarifies the principles for recognizing revenue based on the core principle that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In August 2015, the FASB deferred the effective date of ASU 2014-09, which is now effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the cumulative catchup transition method). The Partnership expects to adopt ASU 2014-09 in the first quarter of 2018 and will apply the cumulative catch-up transition method. We are in the process of evaluating our revenue contracts by segment and fee type to determine the potential impact of adopting the new standards. At this point in our evaluation process, we have determined that the timing and/or amount of revenue that we recognize on certain contracts will be impacted by the adoption of the new standard; however, we are still in the process of quantifying these impacts and cannot say whether or not they would be material to our financial statements. In addition, we are in the process of implementing appropriate changes to our business processes, systems and controls to support recognition and disclosure under the new standard. We continue to monitor additional authoritative or interpretive guidance related to the new standard as it becomes available, as well as comparing our conclusions on specific interpretative issues to other peers in our industry, to the extent that such information is available to us. FASB ASU No. 2016-02. In February 2016, the FASB issued Accounting Standards Update No. 2016-02 “Leases (Topic 842)”, which amends the FASB Accounting Standards Codification and creates Topic 842, Leases. This Topic requires Balance Sheet recognition of lease assets and lease liabilities for leases classified as operating leases under previous GAAP, excluding short-term leases of 12 months or less. This ASU is effective for financial statements issued for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. We are currently evaluating the effect that the updated standard will have on our consolidated balance sheets and related disclosures. We are in the process of evaluating our lease contracts to determine the potential impact of adopting the new standards. At this point in our evaluation process, we have determined that the timing and/or amount of lease assets and lease liabilities that we recognize on certain contracts will be impacted by the adoption of the new standard; however, we are still in the process of quantifying these impacts and cannot say whether or not they would be material to our financial statements. In addition, we are in the process of implementing appropriate changes to our business processes, systems and controls to support recognition and disclosure under the new standard. We continue to monitor additional authoritative or interpretive guidance related to the new standard as it becomes available, as well as comparing our conclusions on specific interpretative issues to other peers in our industry, to the extent that such information is available to us. FASB ASU No. 2016-15. In August 2016, the FASB issued ASU No. 2016-15 “Statement of Cash Flows (Topic 230)” which institutes a number of modifications to presentation and classification of certain cash receipts and cash payments in the statement of cash flows. These modifications include (a) debt prepayment or debt extinguishment costs, (b) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (c) contingent consideration payments made after a business combination, (d) proceeds received from the settlement of insurance claims, (e) proceeds from the settlement of corporate-owned life insurance policies, (f) distributions received from equity method investees, (g) beneficial interest obtained in a securitization of financial assets, (h) separately identifiable cash flows and application of the predominance principle. This ASU is effective for financial statements issued for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. We are currently evaluating the effect that the updated standard will have on our consolidated statements of cash flows and related disclosures. FASB ASU No. 2016-16. In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Income Taxes (Topic 740): Intra-entity Transfers of Assets Other Than Inventory (“ASU 2016-16”), which requires that entities recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amendments in this update do not change GAAP for the pre-tax effects of an intra-entity asset transfer under Topic 810, Consolidation, or for an intra-entity transfer of inventory. ASU 2016-16 is effective for fiscal years beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted. The Partnership is currently evaluating the impact that adoption of this standard will have on the consolidated financial statements and related disclosures. FASB ASU No. 2017-04. In January 2017, the FASB issued ASU No. 2017-04 “Intangibles-Goodwill and other (Topic 350): Simplifying The Test For Goodwill Impairment”. The amendments in this update remove the second step of the two-step test currently required by Topic 350. An entity will apply a one-step quantitative test and record the amount of goodwill impairment as the excess of a reporting unit's carrying amount over its fair value, not to exceed the total amount of goodwill allocated to the reporting unit. The new guidance does not amend the optional qualitative assessment of goodwill impairment. This ASU is effective for financial statements issued for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. The Partnership adopted this ASU on April 1, 2017, which had no impact on the consolidated financial statements at the time of adoption. This accounting guidance was utilized in the goodwill impairment tests performed during the three months ended June 30, 2016, which are discussed in Note 4.

Recently Issued Accounting Pronouncements

FASB ASU No. 2014-09. In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") No. 2014-09, "Revenue from Contracts with Customers (Topic 606)" (“ASU 2014-09”), which clarifies the principles for recognizing revenue based on the core principle that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.

In August 2015, the FASB deferred the effective date of ASU 2014-09, which is now effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the cumulative catchup transition method). The Partnership expects to adopt ASU 2014-09 in the first quarter of 2018 and will apply the cumulative catch-up transition method.

We are in the process of evaluating our revenue contracts by segment and fee type to determine the potential impact of adopting the new standards. At this point in our evaluation process, we have determined that the timing and/or amount of revenue that we recognize on certain contracts will be impacted by the adoption of the new standard; however, we are still in the process of quantifying these impacts and cannot say whether or not they would be material to our financial statements. In addition, we are in the process of implementing appropriate changes to our business processes, systems and controls to support recognition and disclosure under the new standard. We continue to monitor additional authoritative or interpretive guidance related to the new standard as it becomes available, as well as comparing our conclusions on specific interpretative issues to other peers in our industry, to the extent that such information is available to us.

FASB ASU No. 2016-02. In February 2016, the FASB issued Accounting Standards Update No. 2016-02 “Leases (Topic 842)”, which amends the FASB Accounting Standards Codification and creates Topic 842, Leases. This Topic requires Balance Sheet recognition of lease assets and lease liabilities for leases classified as operating leases under previous GAAP, excluding short-term leases of 12 months or less. This ASU is effective for financial statements issued for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. We are currently evaluating the effect that the updated standard will have on our consolidated balance sheets and related disclosures.

We are in the process of evaluating our lease contracts to determine the potential impact of adopting the new standards. At this point in our evaluation process, we have determined that the timing and/or amount of lease assets and lease liabilities that we recognize on certain contracts will be impacted by the adoption of the new standard; however, we are still in the process of quantifying these impacts and cannot say whether or not they would be material to our financial statements. In addition, we are in the process of implementing appropriate changes to our business processes, systems and controls to support recognition and disclosure under the new standard. We continue to monitor additional authoritative or interpretive guidance related to the new standard as it becomes available, as well as comparing our conclusions on specific interpretative issues to other peers in our industry, to the extent that such information is available to us.

FASB ASU No. 2016-15. In August 2016, the FASB issued ASU No. 2016-15 “Statement of Cash Flows (Topic 230)” which institutes a number of modifications to presentation and classification of certain cash receipts and cash payments in the statement of cash flows. These modifications include (a) debt prepayment or debt extinguishment costs, (b) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (c) contingent consideration payments made after a business combination, (d) proceeds received from the settlement of insurance claims, (e) proceeds from the settlement of corporate-owned life insurance policies, (f) distributions received from equity method investees, (g) beneficial interest obtained in a securitization of financial assets, (h) separately identifiable cash flows and application of the predominance principle. This ASU is effective for financial statements issued for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. We are currently evaluating the effect that the updated standard will have on our consolidated statements of cash flows and related disclosures.

FASB ASU No. 2016-16. In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Income Taxes (Topic 740): Intra-entity Transfers of Assets Other Than Inventory (“ASU 2016-16”), which requires that entities recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amendments in this update do not change GAAP for the pre-tax effects of an intra-entity asset transfer under Topic 810, Consolidation, or for an intra-entity transfer of inventory. ASU 2016-16 is effective for fiscal years beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted. The Partnership is currently evaluating the impact that adoption of this standard will have on the consolidated financial statements and related disclosures.

FASB ASU No. 2017-04. In January 2017, the FASB issued ASU No. 2017-04 “Intangibles-Goodwill and other (Topic 350): Simplifying The Test For Goodwill Impairment”. The amendments in this update remove the second step of the two-step test currently required by Topic 350. An entity will apply a one-step quantitative test and record the amount of goodwill impairment as the excess of a reporting unit's carrying amount over its fair value, not to exceed the total amount of goodwill allocated to the reporting unit. The new guidance does not amend the optional qualitative assessment of goodwill impairment. This ASU is effective for financial statements issued for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with early adoption permitted. The Partnership adopted this ASU on April 1, 2017, which had no impact on the consolidated financial statements at the time of adoption. This accounting guidance was utilized in the goodwill impairment tests performed during the three months ended June 30, 2016, which are discussed in Note 4.