Debt, Revolver and Senior Notes (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Revolving Credit Facility
Revolving Credit Facility
Total loan availability	$ 575,000,000
Maximum loan availability	650,000,000
Borrowings under Revolving Credit Facility	0		0
Letters of credit, amount outstanding	300,000
Unused loan availability	574,700,000
Maturity date	Dec. 31, 2017
Commitment Fee (unused portion)	0.50%	[1]
Collateral, Revolving Credit Facility	Our Revolving Credit Facility is non-recourse to Tesoro, except for TLGP, and is guaranteed by all of our subsidiaries and secured by substantially all of our assets.
Base Rate | Revolving Credit Facility
Revolving Credit Facility
Reference Rate Percent	3.25%	[1]
Eurodollar or Base Rate Margin	1.50%	[1]
Eurodollar | Revolving Credit Facility
Revolving Credit Facility
Reference Rate Percent	0.15%	[1]
Eurodollar or Base Rate Margin	2.50%	[1]
Registration Rights Agreement | 5.875% TLLP Senior Notes due 2020
Debt Instrument
Debt Instrument, Face Amount	$ 250,000,000

[1] We have the option to elect if the borrowings will bear interest at either a base rate plus the base rate margin, or a Eurodollar rate, for the applicable period, plus the Eurodollar margin at the time of the borrowing. The applicable margin varies based upon a certain leverage ratio, as defined by the Revolving Credit Facility. We also incur commitment fees for the unused portion of the Revolving Credit Facility at an annual rate. Letters of credit outstanding under the Revolving Credit Facility incur fees at the Eurodollar margin rate.