Basis of Presentation (Notes)	3 Months Ended
Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION As used in this report, the terms “Tesoro,” “we,” “us” or “our” may refer to Tesoro Corporation, one or more of its consolidated subsidiaries or all of them taken as a whole. The words “we,” “us” or “our” generally include Tesoro Logistics LP (“TLLP”) and its subsidiaries as consolidated subsidiaries of Tesoro Corporation with certain exceptions where there are transactions or obligations between TLLP and Tesoro Corporation or its other subsidiaries. When used in descriptions of agreements and transactions, “TLLP” or the “Partnership” refers to TLLP and its consolidated subsidiaries, including its 58% interest in QEP Midstream Partners, LP (“QEPM”), a publicly traded limited partnership, and its subsidiaries. The interim condensed consolidated financial statements and notes thereto of Tesoro Corporation and its subsidiaries have been prepared by management without audit according to the rules and regulations of the Securities and Exchange Commission (“SEC”). The accompanying condensed consolidated financial statements reflect all adjustments that, in the opinion of management, are necessary for a fair presentation of results for the periods presented. Such adjustments are of a normal recurring nature, unless otherwise disclosed. The consolidated balance sheet at December 31, 2014 has been condensed from the audited consolidated financial statements at that date. Certain information and notes normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to the SEC’s rules and regulations. However, management believes that the disclosures presented herein are adequate to present the information fairly. The accompanying condensed consolidated financial statements and notes should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2014. We prepare our condensed consolidated financial statements in conformity with U.S. GAAP, which requires management to make estimates and assumptions that affect the reported amounts and disclosures of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the periods presented. We review our estimates on an ongoing basis. Changes in facts and circumstances may result in revised estimates and actual results could differ from those estimates. The results of operations for any interim period are not necessarily indicative of results for the full year. Certain prior year balances have been aggregated or disaggregated in order to conform to the current year presentation. Due to there being no adjustments to accumulated other comprehensive income for the three months ended March 31, 2015 and 2014, consolidated statements of comprehensive income have been omitted. Our condensed consolidated financial statements include TLLP, a variable interest entity. As the general partner of TLLP, we have the sole ability to direct the activities of TLLP that most significantly impact its economic performance. We are also considered to be the primary beneficiary for accounting purposes and are TLLP’s primary customer. Under our various long-term, fee-based commercial agreements with TLLP, transactions with us accounted for 56% and 88% of TLLP’s total revenues for the three months ended March 31, 2015 and 2014, respectively. In the event TLLP incurs a loss, our operating results will reflect TLLP’s loss, net of intercompany eliminations. See Note 2 for additional information relating to TLLP. On September 25, 2013, we completed the sale of all of our interest in Tesoro Hawaii, LLC, which operated a 94 thousand barrel per day Hawaii refinery, retail stations and associated logistics assets (the “Hawaii Business”). The results of operations for this business have been presented as discontinued operations in the condensed statements of consolidated operations for the three months ended March 31, 2015 and 2014. There were no revenues for either the three months ended March 31, 2015 or 2014. We recorded losses, before and after tax of $1 million for the three months ended March 31, 2014 related to the Hawaii Business. There were no recorded losses, before or after tax, for the three months ended March 31, 2015. There were no cash flows for either the three months ended March 31, 2015 or 2014. Unless otherwise noted, the information in the notes to the condensed consolidated financial statements relates to our continuing operations. New Accounting Standards and Disclosures Revenue Recognition. The Financial Accounting Standards Board (“FASB”) issued an Accounting Standards Update (“ASU”) in May 2014 providing accounting guidance for all revenue arising from contracts to provide goods or services to customers. The requirements from the new ASU are effective for interim and annual periods beginning after December 15, 2016, and early adoption is not permitted. The FASB has proposed a one-year deferral of the effective date; however, this proposal has not been finalized. The standard allows for either full retrospective adoption or modified retrospective adoption. At this time, we are evaluating the guidance to determine the method of adoption and the impact of this ASU on our financial statements and related disclosures. Debt Issuance Costs. In April 2015, the FASB issued ASU 2015-03 which will simplify the presentation of debt issuance costs. Under the new ASU, debt issuance costs related to a recognized debt liability will be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability. As a result, our balance sheet will reflect a reclassification of unamortized debt issuance costs from other noncurrent assets to debt. This ASU is effective for interim and annual periods beginning after December 15, 2015, and early adoption is permitted. We have adopted this standard effective as of March 31, 2015 and applied the changes retrospectively to the prior periods presented. Adoption of this standard has resulted in the reclassification of $93 million from other noncurrent assets to debt on the balance sheet at December 31, 2014. Unamortized debt issuance costs of $89 million are recorded as a reduction to debt on the balance sheet at March 31, 2015.

BASIS OF PRESENTATION

As used in this report, the terms “Tesoro,” “we,” “us” or “our” may refer to Tesoro Corporation, one or more of its consolidated subsidiaries or all of them taken as a whole. The words “we,” “us” or “our” generally include Tesoro Logistics LP (“TLLP”) and its subsidiaries as consolidated subsidiaries of Tesoro Corporation with certain exceptions where there are transactions or obligations between TLLP and Tesoro Corporation or its other subsidiaries. When used in descriptions of agreements and transactions, “TLLP” or the “Partnership” refers to TLLP and its consolidated subsidiaries, including its 58% interest in QEP Midstream Partners, LP (“QEPM”), a publicly traded limited partnership, and its subsidiaries.

The interim condensed consolidated financial statements and notes thereto of Tesoro Corporation and its subsidiaries have been prepared by management without audit according to the rules and regulations of the Securities and Exchange Commission (“SEC”). The accompanying condensed consolidated financial statements reflect all adjustments that, in the opinion of management, are necessary for a fair presentation of results for the periods presented. Such adjustments are of a normal recurring nature, unless otherwise disclosed.

The consolidated balance sheet at December 31, 2014 has been condensed from the audited consolidated financial statements at that date. Certain information and notes normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to the SEC’s rules and regulations. However, management believes that the disclosures presented herein are adequate to present the information fairly. The accompanying condensed consolidated financial statements and notes should be read in conjunction with our Annual Report on Form 10-K for the year ended December 31, 2014.

We prepare our condensed consolidated financial statements in conformity with U.S. GAAP, which requires management to make estimates and assumptions that affect the reported amounts and disclosures of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the periods presented. We review our estimates on an ongoing basis. Changes in facts and circumstances may result in revised estimates and actual results could differ from those estimates. The results of operations for any interim period are not necessarily indicative of results for the full year. Certain prior year balances have been aggregated or disaggregated in order to conform to the current year presentation. Due to there being no adjustments to accumulated other comprehensive income for the three months ended March 31, 2015 and 2014, consolidated statements of comprehensive income have been omitted.

Our condensed consolidated financial statements include TLLP, a variable interest entity. As the general partner of TLLP, we have the sole ability to direct the activities of TLLP that most significantly impact its economic performance. We are also considered to be the primary beneficiary for accounting purposes and are TLLP’s primary customer. Under our various long-term, fee-based commercial agreements with TLLP, transactions with us accounted for 56% and 88% of TLLP’s total revenues for the three months ended March 31, 2015 and 2014, respectively. In the event TLLP incurs a loss, our operating results will reflect TLLP’s loss, net of intercompany eliminations. See Note 2 for additional information relating to TLLP.

On September 25, 2013, we completed the sale of all of our interest in Tesoro Hawaii, LLC, which operated a 94 thousand barrel per day Hawaii refinery, retail stations and associated logistics assets (the “Hawaii Business”). The results of operations for this business have been presented as discontinued operations in the condensed statements of consolidated operations for the three months ended March 31, 2015 and 2014. There were no revenues for either the three months ended March 31, 2015 or 2014. We recorded losses, before and after tax of $1 million for the three months ended March 31, 2014 related to the Hawaii Business. There were no recorded losses, before or after tax, for the three months ended March 31, 2015. There were no cash flows for either the three months ended March 31, 2015 or 2014. Unless otherwise noted, the information in the notes to the condensed consolidated financial statements relates to our continuing operations.

New Accounting Standards and Disclosures

Revenue Recognition. The Financial Accounting Standards Board (“FASB”) issued an Accounting Standards Update (“ASU”) in May 2014 providing accounting guidance for all revenue arising from contracts to provide goods or services to customers. The requirements from the new ASU are effective for interim and annual periods beginning after December 15, 2016, and early adoption is not permitted. The FASB has proposed a one-year deferral of the effective date; however, this proposal has not been finalized. The standard allows for either full retrospective adoption or modified retrospective adoption. At this time, we are evaluating the guidance to determine the method of adoption and the impact of this ASU on our financial statements and related disclosures.

Debt Issuance Costs. In April 2015, the FASB issued ASU 2015-03 which will simplify the presentation of debt issuance costs. Under the new ASU, debt issuance costs related to a recognized debt liability will be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability. As a result, our balance sheet will reflect a reclassification of unamortized debt issuance costs from other noncurrent assets to debt. This ASU is effective for interim and annual periods beginning after December 15, 2015, and early adoption is permitted. We have adopted this standard effective as of March 31, 2015 and applied the changes retrospectively to the prior periods presented. Adoption of this standard has resulted in the reclassification of $93 million from other noncurrent assets to debt on the balance sheet at December 31, 2014. Unamortized debt issuance costs of $89 million are recorded as a reduction to debt on the balance sheet at March 31, 2015.