Equity, Units Rollforward (Details)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Common units outstanding (units)	39,199,766		39,148,916
Tesoro owned subordinated units outstanding (units)	15,254,890		15,254,890
General partner units outstanding (units)	1,110,282		1,110,282
General partner’s ownership interest	2.00%	2.00%
Affiliated partner ownership interest	36.40%
Units issued, unit-based compensation (units)	50,850
Units withheld for taxes (units)	22,595
Public common units
Common units outstanding (units)	35,343,942
Tesoro common units
Common units outstanding (units)	3,855,824
Subordinated
Tesoro owned subordinated units outstanding (units)	15,254,890
General Partner
General partner units outstanding (units)	1,110,282