Debt, Revolving Credit Facility and Exchange Offer (Details) (USD $)	6 Months Ended
	Jun. 30, 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	227,600,000		0
Letters of credit, amount outstanding	300,000
Unused loan availability	347,100,000
Weighted average interest rate	2.78%
Revolver maturity date	Dec. 31, 2017
Revolving Credit Facility, collateral	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.
Commitment Fee (unused portion)	0.50%	[1]
Revolving Credit Facility | Eurodollar
Revolving Credit Facility
Eurodollar or Base Rate	0.16%	[1]
Eurodollar or Base Rate Margin	2.50%	[1]
Revolving Credit Facility | Base Rate
Revolving Credit Facility
Eurodollar or Base Rate	3.25%	[1]
Eurodollar or Base Rate Margin	1.50%	[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.