Debt, Credit Facilities (Details)		Nov. 07, 2019 USD ($)	Sep. 30, 2019 CAD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Valero Revolver [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount				$ 4,000,000,000	$ 4,000,000,000	$ 3,000,000,000
Outstanding borrowings or letters of credit issued				0
Availability				3,966,000,000
Valero Revolver Letter of Credit [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount					$ 2,400,000,000
Outstanding borrowings or letters of credit issued	[1]			34,000,000
Canadian Revolver [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount	[2]		$ 150,000,000
Outstanding borrowings, short-term	[2]		0
Availability	[2]		145,000,000
Canadian Revolver Letter of Credit [Member] | Credit Facilities [Member]
Line of Credit Facility
Outstanding borrowings, short-term	[1],[2]		$ 5,000,000
Accounts Receivable Sales Facility [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount				1,300,000,000
Outstanding borrowings, short-term				100,000,000
Availability				1,200,000,000
Committed Letter of Credit Facility Expires November 2019 [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount	[3]			100,000,000
Outstanding borrowings, short-term	[1],[3]			0
Availability	[3]			100,000,000
Committed Letter of Credit Facility Expires November 2019 [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount				100,000,000
Committed Letter of Credit Facility Expires November 2019 [Member] | Credit Facilities [Member] | Subsequent Event [Member]
Line of Credit Facility
Facility amount		$ 50,000,000
IEnova Revolver [Member] | Central Mexico Terminals [Member] | Credit Facilities [Member] | Variable Interest Entities (VIEs) [Member]
Line of Credit Facility
Facility amount	[4]			340,000,000
Outstanding borrowings or letters of credit issued	[4]			257,000,000
Availability	[4]			83,000,000
Uncommitted Letter of Credit Facility [Member] | Credit Facilities [Member]
Line of Credit Facility
Outstanding borrowings, short-term	[1]			$ 129,000,000

[1] Letters of credit issued as of September 30, 2019 expire at various times in 2019 through 2020.

[2] The Canadian Revolver was amended in November 2019 to extend the maturity date from November 2019 to November 2020.

[3] The letter of credit facility was amended in November 2019 to reduce the facility from $100 million to $50 million and to extend the maturity date from November 2019 to November 2020.

[4] Creditors of our VIE do not have recourse against us.