Debt, Credit Facilities (Details) - Mar. 31, 2020		CAD ($)	USD ($)
Valero Revolver [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount			$ 4,000,000,000
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
Outstanding borrowings or letters of credit issued	[1]		34,000,000
Canadian Revolver [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount		$ 150,000,000
Outstanding borrowings or letters of credit issued, short-term		0
Availability		145,000,000
Canadian Revolver Letter of Credit [Member] | Credit Facilities [Member]
Line of Credit Facility
Outstanding borrowings or letters of credit issued, short-term	[1]	$ 5,000,000
Accounts Receivable Sales Facility [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount			1,300,000,000
Outstanding borrowings or letters of credit issued, short-term			400,000,000
Availability			900,000,000
Committed Letter of Credit Facility Expires November 2020 [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount			50,000,000
Outstanding borrowings or letters of credit issued, short-term	[1]		0
Availability			50,000,000
IEnova Revolver [Member] | Central Mexico Terminals [Member] | Credit Facilities [Member]
Line of Credit Facility
Facility amount			510,000,000
IEnova Revolver [Member] | Central Mexico Terminals [Member] | Credit Facilities [Member] | Variable Interest Entities (VIEs) [Member]
Line of Credit Facility
Facility amount	[2]		510,000,000
Outstanding borrowings or letters of credit issued	[2]		418,000,000
Availability	[2]		92,000,000
Uncommitted Letter of Credit Facility [Member] | Credit Facilities [Member]
Line of Credit Facility
Outstanding borrowings or letters of credit issued, short-term	[1]		$ 118,000,000

[1] Letters of credit issued as of March 31, 2020 expire at various times in 2020 through 2021.

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