Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2019
Accounting Policies [Abstract]
Description of Business	Description of Business We own, operate, develop and acquire pipelines and other midstream assets. As of December 31, 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 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 consolidated financial statements and related notes have been prepared under the rules and regulations of the Securities and Exchange Commission (the “SEC”). These rules and regulations conform to the accounting principles contained in the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification, the single source of GAAP. 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 method 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. The following businesses were acquired from our Parent and accounted for as acquisitions of businesses under common control. As such, our consolidated financial statements include the financial results of these businesses, which were derived from the financial statements and accounting records of SPLC and Shell for the periods prior to acquisition. Specifically, such businesses are reflected for the following periods prior to the effective date of such acquisitions by us: •May 2017 Acquisition for periods prior to May 10, 2017; and •December 2017 Acquisition for periods prior to December 1, 2017, including the effect of fully consolidating Odyssey. Our consolidated statements of income, cash flows and changes in (deficit) equity for 2017 consist of the combined results of the May 2017 Acquisition and the December 2017 Acquisition prior to the respective acquisition dates, and the consolidated activity of the Partnership. Our consolidated statements of income exclude the results of these businesses from net income attributable to the Partnership for the periods indicated above by allocating these results to our Parent. See Note 3 — Acquisitions and Divestiture for definitions and additional information. Expense Allocations. Our consolidated statements of income also include expense allocations for certain functions performed by SPLC and Shell on behalf of the above businesses prior to their respective dates of acquisition by us. Such costs are included in either general and administrative expenses or operations and maintenance expenses in the accompanying consolidated statements of income, depending on the nature of the employee’s role in our operations. The expense allocations have been determined on a basis that we, SPLC and Shell consider to be a reasonable reflection of the utilization of the services provided or the benefit received during the periods presented. See Note 4 — Related Party Transactions for details of operating agreements impacting expense allocations, as well as details of related party transactions. Cash. For all consolidated subsidiaries, we establish our own cash accounts for the funding of our operating and investing activities, with the exception of the capital expenditures incurred by SPLC on our behalf and then contributed to us. Funds are not commingled with the cash of other entities. Prior to the acquisition of each of these interests, the cash generated and used by our operations was deposited to Shell Treasury Center (West) Inc. (“STCW”), which was commingled with the cash of other entities controlled by Shell. STCW funded our operating activities, and STCW or an affiliate funded investing activities as needed. Accordingly, we did not record any cash and cash equivalents held by SPLC on our behalf for any period prior to the effective date of each acquisition from Shell.
Principles of Consolidation	Principles of Consolidation Our consolidated financial statements include all subsidiaries where we have control. The assets and liabilities in the accompanying consolidated financial statements have been reflected on a historical basis. All significant intercompany accounts and transactions are eliminated upon consolidation.
Regulation	Regulation Certain businesses are subject to regulation by various authorities including, but not limited to FERC. Regulatory bodies exercise statutory authority over matters such as construction, rates and ratemaking and agreements with customers.
Net Parent Investment	Net Parent Investment Net Parent Investment represents Shell’s historical investment in us, our accumulated net earnings through the date which we completed the acquisition, and the net effect of transactions with, and allocations from, SPLC and Shell.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported of assets, liabilities, revenues and expenses in the accompanying consolidated financial statements and notes. Actual results could differ from those estimates.
Common Control Transactions	Common Control Transactions Assets and businesses acquired from our Parent and its subsidiaries are accounted for as common control transactions whereby the net assets acquired are combined with ours at our Parent’s historical carrying value. If any recognized consideration transferred in such a transaction exceeds the carrying value of the net assets acquired, the excess is treated as a capital distribution to our General Partner, similar to a dividend. If the carrying value of the net assets acquired exceeds any recognized consideration transferred including, if applicable, the fair value of any limited partner units issued, then our Parent would record an impairment and our net assets acquired would be recorded at fair value. To the extent that such transactions require prior periods to be retrospectively adjusted, historical net equity amounts prior to the transaction date are reflected in “Net Parent Investment.” Cash consideration up to the carrying value of net assets acquired is presented as an investing activity in our consolidated statement of cash flows. Cash consideration in excess of the carrying value of net assets acquired is presented as a financing activity in our consolidated statement of cash flows. Assets and businesses sold to our Parent are also common control transactions accounted for using historical carrying value with any resulting gain treated as a contribution from Parent.
Revenue Recognition	Revenue Recognition Our revenues are primarily generated from the transportation, terminaling and storage of crude oil, refined gas and refined petroleum products through our pipelines, terminals and storage tanks. We recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. We recognize revenue through the application of a five-step model, which includes: identification of the contract; identification of the performance obligations; determination of the transaction price; allocation of the transaction price to the performance obligations; and recognition of revenue as the entity satisfies the performance obligations.
Cash and Cash Equivalents	Cash and Cash Equivalents Our cash and cash equivalents includes cash and short-term highly liquid overnight deposits.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable represent valid claims against customers for products sold or services rendered, net of allowances for doubtful accounts. We assess the creditworthiness of our counterparties on an ongoing basis and require security, including prepayments and other forms of collateral, when appropriate. We establish provisions for losses on accounts receivable due from shippers and operators if we determine that we will not collect all or part of the outstanding balance. Outstanding customer receivables are regularly reviewed for possible nonpayment indicators, and allowances for doubtful accounts are recorded based upon management’s estimate of collectability at each balance sheet date.
Other Investments	Equity Method Investments We account for investments where we have the ability to exercise significant influence, but not control, under the equity method of accounting. Income from equity method investments represents our proportionate share of net income generated by the equity method investees. Differences in the basis of the investments and the underlying net asset value of the investees, if any, are amortized into net income over the remaining useful lives of the underlying assets. Equity method investments are assessed for impairment whenever changes in the facts and circumstances indicate a loss in value has occurred, if the loss is deemed to be other than temporary. When the loss is deemed to be other than temporary, the carrying value of the equity method investment is written down to fair value.
Property, Plant and Equipment	Property, Plant and Equipment Our property, plant and equipment is recorded at its historical cost of construction or, upon acquisition, at either the fair value of the assets acquired or the historical carrying value to the entity that placed the asset in service. Expenditures for major renewals and betterments are capitalized while those minor replacement, maintenance and repairs that do not improve or extend asset life are expensed when incurred. For constructed assets, we capitalize all construction-related direct labor and material costs, as well as indirect construction costs. We capitalize interest on certain projects. For 2019, 2018 and 2017, the total amount of interest capitalized was immaterial. We use the straight-line method to depreciate property, plant and equipment based on the estimated useful life of the asset. We report gains or losses on dispositions of fixed assets as Loss (gain) from revision of ARO and disposition of fixed assets in the accompanying consolidated statements of income.
Impairment of Long-lived Assets	Impairment of Long-lived Assets We evaluate long-lived assets of identifiable business activities for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such assets may not be recoverable. These events include a significant decrease in the market value of the asset, changes in the manner in which we intend to use a long-lived asset, decisions to sell an asset and adverse changes in the legal or business environment such as adverse actions by regulators. If an event occurs, which is a determination that involves judgment, we perform an impairment assessment by comparing estimated undiscounted future cash flows associated with the asset to the asset’s net book value. If the net book value exceeds our estimate of undiscounted future cash flows, an impairment is calculated as the amount the net book value exceeds the estimated fair value associated with the asset.
Income Taxes	Income Taxes We are not a taxable entity for U.S. federal income tax purposes or for the majority of states that impose an income tax. Taxes on our net income are generally borne by our partners through the allocation of taxable income. Our income tax expense results from partnership activity in the state of Texas, as conducted by Zydeco, Sand Dollar and Triton. Income tax expense for 2019, 2018 and 2017 was immaterial.
Other Investments	Other InvestmentsWe account for equity investments in entities where we do not have control or significant influence at fair value with changes in fair value recognized in net income when the fair value is readily determinable. For investments without readily determinable fair values, we carry such investments at cost less impairments, if any. These investments are remeasured at fair value either upon the occurrence of an observable price change or upon identification of impairment. These investments are reported as Other investments in our consolidated balance sheets and dividends received are reported in Dividend income from other investments in our consolidated income statements.
Asset Retirement Obligations	Asset Retirement Obligations Asset retirement obligations (“AROs”) represent contractual or regulatory obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset. Our AROs were zero as of both December 31, 2019 and 2018. Our assets include pipelines and terminals that have contractual or regulatory obligations that will need to be settled at retirement. The settlement date of these obligations will depend mostly on the various supply sources that connect to our systems and the ongoing demand for usage in the markets we serve. We expect these supply sources and market demands to continue for the foreseeable future. As the settlement dates of obligations are indeterminate, there is not sufficient information to make a reasonable estimate of the ARO of our remaining assets as of December 31, 2019 and 2018. We continue to evaluate our AROs and future developments could impact the amounts we record.
Pensions and Other Postretirement Benefits	Pensions and Other Postretirement Benefits We do not have our own employees. Employees that work on our pipelines or terminal are employees of SPLC, and we share employees with other SPLC-controlled and non-controlled entities. For presentation of these accompanying consolidated financial statements, our portion of payroll costs and employee benefit plan costs have been allocated as a charge to us by SPLC and Shell Oil Company. Shell Oil Company sponsors various employee pension and postretirement health and life insurance plans. For purposes of these accompanying consolidated financial statements, we are considered to be participating in the benefit plans of Shell Oil Company. We participate in the following defined benefits plans: Shell Oil Pension Plan, Shell Oil Retiree Health Care Plan, and Pennzoil-Quaker State Retiree Medical & Life Insurance. As a participant in these benefit plans, we recognize as expense in each period an allocation from Shell Oil Company, and we do not recognize any employee benefit plan assets or liabilities. See Note 4 — Related Party Transactions for total pension and benefit expenses under these plans.
Legal	Legal We are subject to litigation and regulatory proceedings as the result of our business operations and transactions. We use both internal and external counsel in evaluating our potential exposure to adverse outcomes from orders, judgments or settlements. In general, we expense legal costs as incurred. When we identify specific litigation that is expected to continue for a significant period of time, is probable to occur and may require substantial expenditures, we identify a range of possible costs expected to be required to litigate the matter to a conclusion or reach an acceptable settlement, and we accrue for the most probable outcome. To the extent that actual outcomes differ from our estimates, or additional facts and circumstances cause us to revise our estimates, our earnings will be affected.
Environmental Matters	Environmental Matters We are subject to federal, state, and local environmental laws and regulations. Environmental expenditures are expensed or capitalized depending on their economic benefit. We expense costs such as permits, compliance with existing environmental regulations, remedial investigations, soil sampling, testing and monitoring costs to meet applicable environmental laws and regulations where prudently incurred or determined to be reasonably possible in the ordinary course of business. We are permitted to recover such expenditures through tariff rates charged to customers. We also expense costs that relate to an existing condition caused by past environmental incidents, which do not contribute to current or future revenue generation. We record environmental liabilities when environmental assessments and/or remedial efforts are probable and we can reasonably estimate the costs. Generally, our recording of these accruals coincides with our completion of a feasibility study or our commitment to a formal plan of action. We recognize receivables for anticipated associated insurance recoveries when such recoveries are deemed to be probable. For 2019, 2018 and 2017, the environmental cleanup costs incurred were immaterial. At both December 31, 2019 and 2018, the accruals for environmental clean-up costs pursuant to a Consent Decree issued in 1998 by the State of Washington Department of Ecology with respect to our products terminal located in Seattle, Washington were immaterial. The costs relate to ongoing groundwater compliance monitoring and other remedial activities. Refer to Note 4 — Related Party Transactions under the Omnibus Agreement for additional details. We routinely conduct reviews of potential environmental issues and claims that could impact our assets or operations. These reviews assist us in identifying environmental issues and estimating the costs and timing of remediation efforts. In making environmental liability estimations, we consider the material effect of environmental compliance, pending legal actions against us and potential third-party liability claims. Often, as the remediation evaluation and effort progresses, additional information is obtained, requiring revisions to estimated costs. These revisions are reflected in our income statement in the period in which they are probable and reasonably estimable.
Other Contingencies	Other Contingencies We recognize liabilities for other contingencies when we have an exposure that indicates it is both probable that a liability has been incurred and the amount of loss can be reasonably estimated. Where the most likely outcome of a contingency can be reasonably estimated, we accrue a liability for that amount. Where the most likely outcome cannot be estimated, a range of potential losses is established and if no one amount in that range is more likely than any other, the lower end of the range is accrued.
Fair Value Estimates	Fair Value Estimates We measure assets and liabilities requiring fair value presentation or disclosure using an exit price (i.e., the price that would be received to sell an asset or paid to transfer a liability) and disclose such amounts according to the quality of valuation inputs under the following hierarchy: Level 1: Quoted prices in an active market for identical assets or liabilities. Level 2: Inputs other than quoted prices that are directly or indirectly observable. Level 3: Unobservable inputs that are significant to the fair value of assets or liabilities. We classify the fair value of an asset or liability based on the lowest level of input significant to its measurement. A fair value initially reported as Level 3 will be subsequently reported as Level 2 if the unobservable inputs become inconsequential to its measurement or corroborating market data becomes available. Asset and liability fair values initially reported as Level 2 will be subsequently reported as Level 3 if corroborating market data becomes unavailable. The carrying amounts of our accounts receivable, accounts payable and accrued liabilities approximate their fair values due to their short-term nature.
Net Income per Limited Partner Unit	Net income per limited partner unit Net income per unit applicable to common limited partner units, and to subordinated limited partner units in periods prior to the expiration of the subordination period, is computed by dividing the respective limited partners’ interest in net income attributable to the Partnership for the period by the weighted average number of common units and subordinated units, respectively, outstanding for the period. Because we have more than one class of participating securities, we use the two-class method when calculating the net income per unit applicable to limited partners. The classes of participating securities include common units, subordinated units, general partner units and incentive distribution rights (“IDRs”). Basic and diluted net income per unit are the same because we do not have any potentially dilutive units outstanding for the period presented. Our net income includes earnings related to businesses acquired through transactions between entities under common control for periods prior to their acquisition by us. We have allocated these pre-acquisition earnings to our Net Parent Investment.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Standards Adopted as of January 1, 2019 In May 2014, the FASB issued Accounting Standards Update (“ASU”) 2014-09 to Topic 606, Revenue from Contracts with Customers, which superseded revenue recognition guidance in Topic 605, Revenue Recognition, under GAAP. Under the revenue standard (as defined in Note 12 — Revenue Recognition), the adoption date for the majority of the equity method investments within the Partnership followed the non-public business entity adoption date of January 1, 2019 for their stand-alone financial statements, with the exception of Mars and Permian Basin, which adopted on January 1, 2018. See Note 5 — Equity Method Investments for additional information. In February 2016, the FASB issued ASU 2016-02 to Topic 842, Leases. As permitted, we adopted the new lease standard (as defined in Note 9 — Leases) 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. Under the new lease standard, the adoption date for equity method investments within the Partnership will follow the non-public business entity adoption date of January 1, 2020 or 2021 for their stand-alone financial statements, with the exception of Permian Basin, which adopted on January 1, 2019. See Note 9 — Leases for additional information and disclosures required by the new lease standard. Standards Not Adopted as of December 31, 2019 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 for SEC filers excluding smaller reporting companies. Early adoption is permitted. We do not expect the adoption of this standard to have a material impact on our consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

We own, operate, develop and acquire pipelines and other midstream assets. As of December 31, 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

Our 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 consolidated financial statements and related notes have been prepared under the rules and regulations of the

Securities and Exchange Commission (the “SEC”). These rules and regulations conform to the accounting principles contained in the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification, the single source of GAAP.

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 method 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. The following businesses were acquired from our Parent and accounted for as acquisitions of businesses under common control. As such, our consolidated financial statements include the financial results of these businesses, which were derived from the financial statements and accounting records of SPLC and Shell for the periods prior to acquisition. Specifically, such businesses are reflected for the following periods prior to the effective date of such acquisitions by us:

•May 2017 Acquisition for periods prior to May 10, 2017; and

•December 2017 Acquisition for periods prior to December 1, 2017, including the effect of fully consolidating Odyssey.

Our consolidated statements of income, cash flows and changes in (deficit) equity for 2017 consist of the combined results of the May 2017 Acquisition and the December 2017 Acquisition prior to the respective acquisition dates, and the consolidated activity of the Partnership. Our consolidated statements of income exclude the results of these businesses from net income attributable to the Partnership for the periods indicated above by allocating these results to our Parent. See Note 3 — Acquisitions and Divestiture for definitions and additional information.

Expense Allocations. Our consolidated statements of income also include expense allocations for certain functions performed by SPLC and Shell on behalf of the above businesses prior to their respective dates of acquisition by us. Such costs are included in either general and administrative expenses or operations and maintenance expenses in the accompanying consolidated statements of income, depending on the nature of the employee’s role in our operations. The expense allocations have been determined on a basis that we, SPLC and Shell consider to be a reasonable reflection of the utilization of the services provided or the benefit received during the periods presented.

See Note 4 — Related Party Transactions for details of operating agreements impacting expense allocations, as well as details of related party transactions.

Cash. For all consolidated subsidiaries, we establish our own cash accounts for the funding of our operating and investing activities, with the exception of the capital expenditures incurred by SPLC on our behalf and then contributed to us. Funds are not commingled with the cash of other entities. Prior to the acquisition of each of these interests, the cash generated and used by our operations was deposited to Shell Treasury Center (West) Inc. (“STCW”), which was commingled with the cash of other entities controlled by Shell. STCW funded our operating activities, and STCW or an affiliate funded investing activities as needed. Accordingly, we did not record any cash and cash equivalents held by SPLC on our behalf for any period prior to the effective date of each acquisition from Shell.

Principles of Consolidation

Principles of Consolidation Our consolidated financial statements include all subsidiaries where we have control. The assets and liabilities in the accompanying consolidated financial statements have been reflected on a historical basis. All significant intercompany accounts and transactions are eliminated upon consolidation.

Regulation

Regulation Certain businesses are subject to regulation by various authorities including, but not limited to FERC. Regulatory bodies exercise statutory authority over matters such as construction, rates and ratemaking and agreements with customers.

Net Parent Investment

Net Parent Investment Net Parent Investment represents Shell’s historical investment in us, our accumulated net earnings through the date which we completed the acquisition, and the net effect of transactions with, and allocations from, SPLC and Shell.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported of assets, liabilities, revenues and expenses in the accompanying consolidated financial statements and notes. Actual results could differ from those estimates.

Common Control Transactions

Assets and businesses acquired from our Parent and its subsidiaries are accounted for as common control transactions whereby the net assets acquired are combined with ours at our Parent’s historical carrying value. If any recognized consideration transferred in such a transaction exceeds the carrying value of the net assets acquired, the excess is treated as a capital distribution to our General Partner, similar to a dividend. If the carrying value of the net assets acquired exceeds any recognized consideration transferred including, if applicable, the fair value of any limited partner units issued, then our Parent would record an impairment and our net assets acquired would be recorded at fair value. To the extent that such transactions require prior periods to be retrospectively adjusted, historical net equity amounts prior to the transaction date are reflected in “Net Parent Investment.” Cash consideration up to the carrying value of net assets acquired is presented as an investing activity in our consolidated statement of cash flows. Cash consideration in excess of the carrying value of net assets acquired is presented as a financing activity in our consolidated statement of cash flows. Assets and businesses sold to our Parent are also common control transactions accounted for using historical carrying value with any resulting gain treated as a contribution from Parent.

Revenue Recognition

Revenue Recognition Our revenues are primarily generated from the transportation, terminaling and storage of crude oil, refined gas and refined petroleum products through our pipelines, terminals and storage tanks. We recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. We recognize revenue through the application of a five-step model, which includes: identification of the contract; identification of the performance obligations; determination of the transaction price; allocation of the transaction price to the performance obligations; and recognition of revenue as the entity satisfies the performance obligations.

Cash and Cash Equivalents

Our cash and cash equivalents includes cash and short-term highly liquid overnight deposits.

Accounts Receivable and Allowance for Doubtful Accounts

Accounts receivable represent valid claims against customers for products sold or services rendered, net of allowances for

doubtful accounts. We assess the creditworthiness of our counterparties on an ongoing basis and require security, including

prepayments and other forms of collateral, when appropriate. We establish provisions for losses on accounts receivable due

from shippers and operators if we determine that we will not collect all or part of the outstanding balance. Outstanding

customer receivables are regularly reviewed for possible nonpayment indicators, and allowances for doubtful accounts are

recorded based upon management’s estimate of collectability at each balance sheet date.

Other Investments

Equity Method Investments We account for investments where we have the ability to exercise significant influence, but not control, under the equity method of accounting. Income from equity method investments represents our proportionate share of net income generated by the equity method investees. Differences in the basis of the investments and the underlying net asset value of the investees, if any, are amortized into net income over the remaining useful lives of the underlying assets. Equity method investments are assessed for impairment whenever changes in the facts and circumstances indicate a loss in value has occurred, if the loss is deemed to be other than temporary. When the loss is deemed to be other than temporary, the carrying value of the equity method investment is written down to fair value.

Property, Plant and Equipment

Our property, plant and equipment is recorded at its historical cost of construction or, upon acquisition, at either the fair value of the assets acquired or the historical carrying value to the entity that placed the asset in service. Expenditures for major renewals and betterments are capitalized while those minor replacement, maintenance and repairs that do not improve or extend asset life are expensed when incurred. For constructed assets, we capitalize all construction-related direct labor and material

costs, as well as indirect construction costs. We capitalize interest on certain projects. For 2019, 2018 and 2017, the total amount of interest capitalized was immaterial. We use the straight-line method to depreciate property, plant and equipment based on the estimated useful life of the asset. We report gains or losses on dispositions of fixed assets as Loss (gain) from revision of ARO and disposition of fixed assets in the accompanying consolidated statements of income.

Impairment of Long-lived Assets

Impairment of Long-lived Assets We evaluate long-lived assets of identifiable business activities for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such assets may not be recoverable. These events include a significant decrease in the market value of the asset, changes in the manner in which we intend to use a long-lived asset, decisions to sell an asset and adverse changes in the legal or business environment such as adverse actions by regulators. If an event occurs, which is a determination that involves judgment, we perform an impairment assessment by comparing estimated undiscounted future cash flows associated with the asset to the asset’s net book value. If the net book value exceeds our estimate of undiscounted future cash flows, an impairment is calculated as the amount the net book value exceeds the estimated fair value associated with the asset.

Income Taxes

We are not a taxable entity for U.S. federal income tax purposes or for the majority of states that impose an income tax. Taxes on our net income are generally borne by our partners through the allocation of taxable income. Our income tax expense results from partnership activity in the state of Texas, as conducted by Zydeco, Sand Dollar and Triton. Income tax expense for 2019, 2018 and 2017 was immaterial.

Other Investments

Other InvestmentsWe account for equity investments in entities where we do not have control or significant influence at fair value with changes in fair value recognized in net income when the fair value is readily determinable. For investments without readily determinable fair values, we carry such investments at cost less impairments, if any. These investments are remeasured at fair value either upon the occurrence of an observable price change or upon identification of impairment. These investments are reported as Other investments in our consolidated balance sheets and dividends received are reported in Dividend income from other investments in our consolidated income statements.

Asset Retirement Obligations

Asset retirement obligations (“AROs”) represent contractual or regulatory obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset. Our AROs were zero as of both December 31, 2019 and 2018.

Our assets include pipelines and terminals that have contractual or regulatory obligations that will need to be settled at retirement. The settlement date of these obligations will depend mostly on the various supply sources that connect to our systems and the ongoing demand for usage in the markets we serve. We expect these supply sources and market demands to

continue for the foreseeable future. As the settlement dates of obligations are indeterminate, there is not sufficient information to make a reasonable estimate of the ARO of our remaining assets as of December 31, 2019 and 2018.

We continue to evaluate our AROs and future developments could impact the amounts we record.

Pensions and Other Postretirement Benefits

Pensions and Other Postretirement Benefits We do not have our own employees. Employees that work on our pipelines or terminal are employees of SPLC, and we share employees with other SPLC-controlled and non-controlled entities. For presentation of these accompanying consolidated financial statements, our portion of payroll costs and employee benefit plan costs have been allocated as a charge to us by SPLC and Shell Oil Company. Shell Oil Company sponsors various employee pension and postretirement health and life insurance plans. For purposes of these accompanying consolidated financial statements, we are considered to be participating in the benefit plans of Shell Oil Company. We participate in the following defined benefits plans: Shell Oil Pension Plan, Shell Oil Retiree Health Care Plan, and Pennzoil-Quaker State Retiree Medical & Life Insurance. As a participant in these benefit plans, we recognize as expense in each period an allocation from Shell Oil Company, and we do not recognize any employee benefit plan assets or liabilities. See Note 4 — Related Party Transactions for total pension and benefit expenses under these plans.

Legal

Legal We are subject to litigation and regulatory proceedings as the result of our business operations and transactions. We use both internal and external counsel in evaluating our potential exposure to adverse outcomes from orders, judgments or settlements. In general, we expense legal costs as incurred. When we identify specific litigation that is expected to continue for a significant period of time, is probable to occur and may require substantial expenditures, we identify a range of possible costs expected to be required to litigate the matter to a conclusion or reach an acceptable settlement, and we accrue for the most probable outcome. To the extent that actual outcomes differ from our estimates, or additional facts and circumstances cause us to revise our estimates, our earnings will be affected.

Environmental Matters

We are subject to federal, state, and local environmental laws and regulations. Environmental expenditures are expensed or capitalized depending on their economic benefit. We expense costs such as permits, compliance with existing environmental regulations, remedial investigations, soil sampling, testing and monitoring costs to meet applicable environmental laws and regulations where prudently incurred or determined to be reasonably possible in the ordinary course of business. We are permitted to recover such expenditures through tariff rates charged to customers. We also expense costs that relate to an existing condition caused by past environmental incidents, which do not contribute to current or future revenue generation. We record environmental liabilities when environmental assessments and/or remedial efforts are probable and we can reasonably estimate the costs. Generally, our recording of these accruals coincides with our completion of a feasibility study or our commitment to a formal plan of action. We recognize receivables for anticipated associated insurance recoveries when such recoveries are deemed to be probable.

For 2019, 2018 and 2017, the environmental cleanup costs incurred were immaterial. At both December 31, 2019 and 2018, the accruals for environmental clean-up costs pursuant to a Consent Decree issued in 1998 by the State of Washington Department of Ecology with respect to our products terminal located in Seattle, Washington were immaterial. The costs relate to ongoing groundwater compliance monitoring and other remedial activities. Refer to Note 4 — Related Party Transactions under the Omnibus Agreement for additional details.

We routinely conduct reviews of potential environmental issues and claims that could impact our assets or operations. These reviews assist us in identifying environmental issues and estimating the costs and timing of remediation efforts. In making environmental liability estimations, we consider the material effect of environmental compliance, pending legal actions against us and potential third-party liability claims. Often, as the remediation evaluation and effort progresses, additional information is obtained, requiring revisions to estimated costs. These revisions are reflected in our income statement in the period in which they are probable and reasonably estimable.

Other Contingencies

Other Contingencies We recognize liabilities for other contingencies when we have an exposure that indicates it is both probable that a liability has been incurred and the amount of loss can be reasonably estimated. Where the most likely outcome of a contingency can be reasonably estimated, we accrue a liability for that amount. Where the most likely outcome cannot be estimated, a range of potential losses is established and if no one amount in that range is more likely than any other, the lower end of the range is accrued.

Fair Value Estimates

We measure assets and liabilities requiring fair value presentation or disclosure using an exit price (i.e., the price that would be received to sell an asset or paid to transfer a liability) and disclose such amounts according to the quality of valuation inputs under the following hierarchy:

Level 1: Quoted prices in an active market for identical assets or liabilities.

Level 2: Inputs other than quoted prices that are directly or indirectly observable.

Level 3: Unobservable inputs that are significant to the fair value of assets or liabilities.

We classify the fair value of an asset or liability based on the lowest level of input significant to its measurement. A fair value initially reported as Level 3 will be subsequently reported as Level 2 if the unobservable inputs become inconsequential to its measurement or corroborating market data becomes available. Asset and liability fair values initially reported as Level 2 will be subsequently reported as Level 3 if corroborating market data becomes unavailable.

The carrying amounts of our accounts receivable, accounts payable and accrued liabilities approximate their fair values due to their short-term nature.

Net Income per Limited Partner Unit

Net income per limited partner unit

Net income per unit applicable to common limited partner units, and to subordinated limited partner units in periods prior to the expiration of the subordination period, is computed by dividing the respective limited partners’ interest in net income attributable to the Partnership for the period by the weighted average number of common units and subordinated units, respectively, outstanding for the period. Because we have more than one class of participating securities, we use the two-class method when calculating the net income per unit applicable to limited partners. The classes of participating securities include common units, subordinated units, general partner units and incentive distribution rights (“IDRs”). Basic and diluted net income per unit are the same because we do not have any potentially dilutive units outstanding for the period presented.

Our net income includes earnings related to businesses acquired through transactions between entities under common control for periods prior to their acquisition by us. We have allocated these pre-acquisition earnings to our Net Parent Investment.

Recent Accounting Pronouncements

Standards Adopted as of January 1, 2019

In May 2014, the FASB issued Accounting Standards Update (“ASU”) 2014-09 to Topic 606, Revenue from Contracts with Customers, which superseded revenue recognition guidance in Topic 605, Revenue Recognition, under GAAP. Under the revenue standard (as defined in Note 12 — Revenue Recognition), the adoption date for the majority of the equity method investments within the Partnership followed the non-public business entity adoption date of January 1, 2019 for their stand-alone financial statements, with the exception of Mars and Permian Basin, which adopted on January 1, 2018. See Note 5 — Equity Method Investments for additional information.

In February 2016, the FASB issued ASU 2016-02 to Topic 842, Leases. As permitted, we adopted the new lease standard (as defined in Note 9 — Leases) 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. Under the new lease standard, the adoption date for equity method investments within the Partnership will follow the non-public business entity adoption date of January 1, 2020 or 2021 for their stand-alone financial statements, with the exception of Permian Basin, which adopted on January 1, 2019. See Note 9 — Leases for additional information and disclosures required by the new lease standard.

Standards Not Adopted as of December 31, 2019

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 for SEC filers excluding smaller reporting companies. Early adoption is permitted. We do not expect the adoption of this standard to have a material impact on our consolidated financial statements.