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Acquisition and Divestitures Acquisition and Divestitures (Policies) | 9 Months Ended
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Sep. 30, 2017
Business Combinations [Abstract] |
Business Combinations Policy [Policy Text Block] | We accounted for the North Dakota Gathering and Processing Assets acquisition using the acquisition method of accounting, which requires, among other things, that assets acquired at their fair values and liabilities assumed be recognized on the balance sheet as of the acquisition date. The purchase price allocation for the North Dakota Gathering and Processing Assets acquisition is preliminary and has been allocated based on estimated fair values of the assets acquired and liabilities assumed at the acquisition date, pending the completion of an independent valuation and other information as it becomes available to us. The purchase price allocation adjustments can be made through the end of Andeavor Logistics’ measurement period, which is not to exceed one year from the acquisition date.

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- Definition Disclosure of accounting policy for completed business combinations (purchase method, acquisition method or combination of entities under common control). This accounting policy may include a general discussion of the purchase method or acquisition method of accounting (including for example, the treatment accorded contingent consideration, the identification of assets and liabilities, the purchase price allocation process, how the fair values of acquired assets and liabilities are determined) and the entity's specific application thereof. An entity that acquires another entity in a leveraged buyout transaction generally discloses the accounting policy followed by the acquiring entity in determining the basis used to value its interest in the acquired entity, and the rationale for that accounting policy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=68058157&loc=d3e18780-107790 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 05 -Paragraph 4 -Subparagraph (a)-(d) -URI http://asc.fasb.org/extlink&oid=6909625&loc=d3e227-128457 + Details
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