Organization, Description of Business And Basis Of Presentation (Policies)	3 Months Ended
	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation In the opinion of management, our accompanying consolidated financial statements which are unaudited, except for the consolidated balance sheet as of December 31, 2019, which is derived from our audited financial statements, include all normal and recurring adjustments necessary to present fairly our financial position as of March 31, 2020, the results of operations for the three months ended March 31, 2019 and 2020 and cash flows for the three months ended March 31, 2019 and 2020. The results of operations for the three months ended March 31, 2020 are not necessarily indicative of the results to be expected for the full year ending December 31, 2020 for several reasons. Profits from our gas liquids blending activities are realized largely during the first and fourth quarters of each year. Additionally, gasoline demand, which drives transportation volumes and revenues on our refined products pipeline system, generally trends higher during the summer driving months. Further, the volatility of commodity prices impacts the profits from our commodity activities and the volume of petroleum products we transport on our pipelines. Finally, we expect the impact of COVID-19 on demand for petroleum products and the decline in commodity prices to be more prevalent in our results of operations in the remaining three quarters of 2020, resulting in decreased transportation and terminalling revenues and reduced profits from our gas liquids blending activities. Pursuant to the rules and regulations of the Securities and Exchange Commission, the financial statements in this report do not include all of the information and notes normally included with financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2019.
Use of Estimates	Use of Estimates The preparation of our consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities that exist at the date of our consolidated financial statements, as well as their impact on the reported amounts of revenue and expense during the reporting periods. Actual results could differ from those estimates.
New Accounting Pronouncements	New Accounting Pronouncements In June 2016, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326). The new guidance is effective for reporting periods beginning after December 15, 2019. The standard replaces the incurred loss impairment methodology under current GAAP with a methodology that reflects expected credit losses and requires the use of a forward-looking expected credit loss model for accounts receivables, loans, and other financial instruments. The standard requires a modified retrospective approach through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. We adopted the new guidance as of January 1, 2020 using the modified retrospective approach related to our accounts receivables and contract assets, resulting in no cumulative adjustment to retained earnings. The adoption of this guidance did not have a material impact on our consolidated statements of income.