Distribution To Holders Of Incentive Distribution Rights Waived

No definition available.

Name:	shlx_DistributionToHoldersOfIncentiveDistributionRightsWaived
Namespace Prefix:	shlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	shlx_PartnersCapitalSaleofUnitsMaximumGrossProceeds
Namespace Prefix:	shlx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_ClassOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage investment held by the managing member or general partner of the limited liability company (LLC) or limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of units sold in a private placement of each class of partners' capital account. Units represent shares of ownership of the general, limited, and preferred partners.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-Subparagraph (SAB Topic 4.F)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

+ Details

Name:	us-gaap_PartnersCapitalAccountUnitsSoldInPrivatePlacement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_GeneralPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=shlx_GeneralPartnerInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=shlx_CommonUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=shlx_ShellPipelineCompanyLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_LimitedPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=shlx_LimitedPartnerInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

(Deficit) Equity (Details) - USD ($)		3 Months Ended			12 Months Ended
(Deficit) Equity (Details) - USD ($)	Mar. 02, 2016	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Issuance of common units, maximum proceeds	$ 300,000,000
Distributions to holders of incentive distribution rights waived		$ 16,000,000	$ 17,000,000	$ 17,000,000	$ 50,000,000
General Partner \| General Partner Interest
Class of Stock [Line Items]
Aggregate percentage of general partner interest		2.00%
Common Units
Class of Stock [Line Items]
Units issued under the ATM Program (in shares)		1,000,000,000
Shell Pipeline Company L P \| General Partner \| General Partner Interest
Class of Stock [Line Items]
Aggregate percentage of general partner interest		2.00%
Shell Pipeline Company L P \| Limited Partner \| Limited Partner Interest
Class of Stock [Line Items]
Aggregate percentage of general partner interest		98.00%