Debt and Capital Lease Obligations, Credit Facilities (Details) - 3 months ended Mar. 31, 2018	CAD ($)	USD ($)
Uncommitted Letter of Credit Facility [Member]
Line of Credit Facility
Amount outstanding		$ 273,000,000
Credit Facilities [Member] \| Valero Revolver [Member]
Line of Credit Facility
Line of credit facility, maximum borrowing capacity		3,000,000,000
Line of credit facility, expiration date	Nov. 30, 2020
Amount outstanding		0
Line of credit facility, remaining borrowing capacity		2,862,000,000
Credit Facilities [Member] \| Valero Revolver Letter of Credit [Member]
Line of Credit Facility
Amount outstanding		138,000,000
Credit Facilities [Member] \| VLP Revolver [Member] \| Valero Energy Partners LP [Member]
Line of Credit Facility
Line of credit facility, maximum borrowing capacity		750,000,000
Line of credit facility, expiration date	Nov. 30, 2020
Amount outstanding		0
Line of credit facility, remaining borrowing capacity		750,000,000
Credit Facilities [Member] \| VLP Revolver Letter of Credit [Member] \| Valero Energy Partners LP [Member]
Line of Credit Facility
Amount outstanding		0
Credit Facilities [Member] \| Canadian Revolver [Member]
Line of Credit Facility
Line of credit facility, maximum borrowing capacity	$ 75,000,000
Line of credit facility, expiration date	Nov. 30, 2018
Amount outstanding	$ 0
Line of credit facility, remaining borrowing capacity	69,000,000
Credit Facilities [Member] \| Canadian Revolver Letter of Credit [Member]
Line of Credit Facility
Amount outstanding	$ 6,000,000
Credit Facilities [Member] \| A/R Sales Facility [Member]
Line of Credit Facility
Line of credit facility, maximum borrowing capacity		1,300,000,000
Line of credit facility, expiration date	Jul. 31, 2018
Amount outstanding		100,000,000
Line of credit facility, remaining borrowing capacity		1,200,000,000
Credit Facilities [Member] \| Committed Letter of Credit Facility Expires November 2018 [Member]
Line of Credit Facility
Line of credit facility, maximum borrowing capacity		100,000,000
Line of credit facility, expiration date	Nov. 30, 2018
Amount outstanding		0
Line of credit facility, remaining borrowing capacity		$ 100,000,000

The carrying value as of the balance sheet date of the current and noncurrent portions 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.

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 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- 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

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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