Additional collateral for debt

No definition available.

Name:	sun_DebtInstrumentAdditionalCollateralForDebt
Namespace Prefix:	sun_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Leverage Ratio

+ References

No definition available.

+ Details

Name:	sun_DebtInstrumentCovenantLeverageRatio
Namespace Prefix:	sun_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Leverage Ratio, Certain Acquisitions

+ References

No definition available.

+ Details

Name:	sun_DebtInstrumentCovenantLeverageRatioCertainAcquisitions
Namespace Prefix:	sun_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Leverage Ratio, Certain Acquisitions Threshold

+ References

No definition available.

+ Details

Name:	sun_DebtInstrumentCovenantLeverageRatioCertainAcquisitionsThreshold
Namespace Prefix:	sun_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maximum the facility can be increased, subject to certain conditions.

+ References

No definition available.

+ Details

Name:	sun_LineOfCreditFacilityAdditionalBorrowingCapacity
Namespace Prefix:	sun_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

+ Details

Name:	us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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

- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=99376301&loc=d3e1314-112600

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=99376301&loc=d3e1336-112600

+ Details

Name:	us-gaap_LongTermLineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_ExternalCreditRatingInvestmentGradeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MediumTermNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TransactionTypeAxis=sun_NodispositionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TransactionTypeAxis=sun_Dispositionof7ElevenassetsorWestTexasAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TransactionTypeAxis=sun_Dispositionof7ElevenassetsandWestTexasassetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt (Revolving Credit Agreement) (Details)			3 Months Ended
Long-Term Debt (Revolving Credit Agreement) (Details)	Mar. 31, 2016 USD ($)	Sep. 25, 2014 USD ($)	Sep. 30, 2016	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017 USD ($)	Sep. 30, 2017	Dec. 31, 2016 USD ($)	Apr. 10, 2015 USD ($)
Debt Instrument [Line Items]
Revolving line of credit									$ 765,000,000		$ 1,000,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 1,250,000,000.00										$ 1,500,000,000.0
Additional borrowing capacity												$ 250,000,000
Additional collateral for debt		66.00%
Revolving line of credit									765,000,000		$ 1,000,000,000
Standby letters									9,000,000
Unused borrowing capacity									$ 726,000,000
Revolving Credit Facility [Member] \| Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.50%
Revolving Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%
Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Commitment fee on unused capacity		0.25%
Revolving Credit Facility [Member] \| Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		1.50%	2.75%
Revolving Credit Facility [Member] \| Minimum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.50%	1.75%
Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Commitment fee on unused capacity		0.50%
Revolving Credit Facility [Member] \| Maximum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		3.00%	3.00%
Revolving Credit Facility [Member] \| Maximum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		2.00%	2.00%
External Credit Rating, Investment Grade [Member] \| Revolving Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		1.125%
External Credit Rating, Investment Grade [Member] \| Revolving Credit Facility [Member] \| Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.125%
External Credit Rating, Investment Grade [Member] \| Revolving Credit Facility [Member] \| Minimum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Commitment fee on unused capacity		0.125%
External Credit Rating, Investment Grade [Member] \| Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		2.00%
Commitment fee on unused capacity		0.275%
External Credit Rating, Investment Grade [Member] \| Revolving Credit Facility [Member] \| Maximum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)									5.50
Revolving Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)									6.00
Term Loan [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)									6.75
Leverage ratio, certain acquisitions (not more than)	6.0
Leverage ratio, certain acquisitions threshold (in excess of)	$ 50,000,000
Term Loan [Member] \| Scenario, Forecast [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)				5.5	5.75	6.0	6.25	6.5
Term Loan [Member] \| Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.50%		2.75%
Term Loan [Member] \| Minimum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%		1.75%
Term Loan [Member] \| Maximum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%		3.00%
Term Loan [Member] \| Maximum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%		2.00%
No disposition [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)									6.75	6.75
No disposition [Member] \| Revolving Credit Facility [Member] \| Scenario, Forecast [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)				5.50	5.75	6.00	6.25	6.50
Disposition of 7-Eleven assets or West Texas Assets [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)									6.00	6.75
Disposition of 7-Eleven assets or West Texas Assets [Member] \| Revolving Credit Facility [Member] \| Scenario, Forecast [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)				5.50	5.50	5.50	5.50	5.75
Disposition of 7-Eleven assets and West Texas assets [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)									5.75	6.75
Disposition of 7-Eleven assets and West Texas assets [Member] \| Revolving Credit Facility [Member] \| Scenario, Forecast [Member]
Debt Instrument [Line Items]
Leverage ratio (not more than)				5.50	5.50	5.50	5.50	5.75