Description of Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business We are a growth-oriented master limited partnership that owns, operates, develops and acquires pipelines and other midstream assets. As of June 30, 2019, our assets include interests in entities that own crude oil and refined products pipelines and terminals that serve as key infrastructure to (i) transport onshore and offshore crude oil production to Gulf Coast and Midwest refining markets and (ii) deliver refined products from those markets to major demand centers. Our assets also include interests in entities that own natural gas and refinery gas pipelines that transport offshore natural gas to market hubs and deliver refinery gas from refineries and plants to chemical sites along the Gulf Coast. We generate revenue from the transportation, terminaling and storage of crude oil and refined products through our pipelines and storage tanks, and generate income from our equity and other investments. Our operations consist of one reportable segment.
Basis of Presentation	Basis of Presentation Our unaudited consolidated financial statements include all 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 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 consolidated balance sheet data was derived from audited financial statements. During interim periods, we follow the accounting policies disclosed in our Annual Report on Form 10-K for the year ended December 31, 2018 (our “2018 Annual Report”), filed with the United States Securities and Exchange Commission (“SEC”) unless otherwise described herein. The unaudited consolidated financial statements for the three and six months ended June 30, 2019 and June 30, 2018 include all adjustments we believe are necessary for a fair statement of the results of operations for the interim periods presented. These adjustments are of a normal recurring nature unless otherwise disclosed. Operating results for the interim periods are not necessarily indicative of the results that may be expected for the full year. These unaudited consolidated financial statements and other information included in this Quarterly Report on Form 10-Q should be read in conjunction with our audited consolidated financial statements and notes thereto included in our 2018 Annual Report.Our consolidated subsidiaries include Pecten, Sand Dollar, Triton, Zydeco, Odyssey and the Operating Company. Asset acquisitions of additional interests in previously consolidated subsidiaries and interests in equity and other investments are included in the financial statements prospectively from the effective date of each acquisition. In cases where these types of acquisitions are considered acquisitions of businesses under common control, the financial statements are retrospectively adjusted.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Standards Adopted as of January 1, 2019 In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2016-02 to Topic 842, Leases. As permitted, we adopted the new standard using the modified retrospective approach, effective January 1, 2019, which provides a method for recording existing leases at the beginning of the period of adoption. As such, results and balances prior to January 1, 2019 are not adjusted and continue to be reported in accordance with our historical accounting under previous GAAP. See Note 8 — Leases for additional information and disclosures required by the new standard. Standards Not Yet Adopted In June 2016, the FASB issued ASU 2016-13 to Topic 326, Financial Instruments — Credit Losses: Measurement of Credit Losses on Financial Instruments, which replaces the current incurred loss impairment method with a method that reflects expected credit losses on financial instruments. The update is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted for fiscal years beginning after December 15, 2018. While we are still evaluating the impact of ASU 2016-13, we do not expect the adoption of this standard to have a material impact on our consolidated financial statements.