Discontinued Operations (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Jan. 22, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tangible Asset Impairment Charges				$ 4
Non-cash compensation expense		$ 13	$ 12	24
7-Eleven Transaction [Member]
Discontinued Operation, Period of Continuing Involvement after Disposal		15 years
Intra-entity revenue previously eliminated in consolidation	$ 199			3,200
Cash received from continuing involvement with discontinued operation		$ 3,700	3,400
Transaction cost			$ 3	37
Non-cash compensation expense				$ 6

Transaction cost

No definition available.

Name:	sun_Transactioncost
Namespace Prefix:	sun_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from (to) the discontinued operation after the disposal transaction.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721665-107760

+ Details

Name:	us-gaap_DiscontinuedOperationAmountOfContinuingCashFlowsAfterDisposal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of revenue in continuing operations related to continuing involvement in a discontinued operation after disposal that before the disposal was eliminated as intra-entity transactions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721665-107760

+ Details

Name:	us-gaap_DiscontinuedOperationIntraEntityAmountsDiscontinuedOperationAfterDisposalRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Period of expected continuing involvement with a discontinued operation after the disposal date, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721665-107760

+ Details

Name:	us-gaap_DiscontinuedOperationPeriodOfContinuingInvolvementAfterDisposal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of noncash expense for share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

+ Details

Name:	us-gaap_ShareBasedCompensation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The charge against earnings resulting from the aggregate write down of tangible assets from their carrying value to their fair value.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=d3e1361-107760

+ Details

Name:	us-gaap_TangibleAssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=sun_A7ElevenTransactionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: