Debt, Credit Facilities (Details)		Jun. 30, 2019 CAD ($)	Jun. 30, 2019 USD ($)	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			3,967,000,000
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]		33,000,000
Canadian Revolver [Member] | Credit Facilities [Member]
Line of Credit Facility
Outstanding borrowings, short-term		$ 0
Canadian Revolver [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount		150,000,000
Availability		145,000,000
Canadian Revolver Letter of Credit [Member] | Credit Facilities [Member]
Line of Credit Facility
Outstanding borrowings or letters of credit issued	[1]	$ 5,000,000
Accounts Receivable Sales Facility [Member] | Credit Facilities [Member]
Line of Credit Facility
Outstanding borrowings, short-term	[2]		100,000,000
Accounts Receivable Sales Facility [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount	[2]		1,300,000,000
Availability	[2]		1,200,000,000
Committed Letter of Credit Facility Expires November 2019 [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount			100,000,000
Outstanding borrowings or letters of credit issued	[1]		0
Availability			100,000,000
IEnova Revolver [Member] | Central Mexico Terminals [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount	[3]		340,000,000
Outstanding borrowings or letters of credit issued	[3]		179,000,000
Availability	[3]		161,000,000
Uncommitted Letter of Credit Facility [Member]
Line of Credit Facility
Outstanding borrowings or letters of credit issued	[1]		$ 279,000,000

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

[2] In July 2019, we amended this facility to extend the maturity date from July 2019 to July 2020.

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