Commitments and Contingencies (Details)	6 Months Ended
	Jun. 30, 2020 USD ($) refinery claim
Long-term Purchase Commitment [Line Items]
Number of owned and operated refineries | refinery	4
Number of remaining claim to be resolved | claim	2
Bankruptcy claims amount of claims to be settled	$ 22,400,000
Estimated value of claims remaining to be settled	500,000
Maximum bankruptcy claims remaining	$ 22,400,000
Predecessor working ownership percentage	3.40%
Allowed claims, settlement ratio	0.0544
Wyoming Refinery One
Long-term Purchase Commitment [Line Items]
Environmental remediation accrual	$ 16,000,000.0
Environmental costs recognized, period for recognition of one third costs	5 years
Environmental costs recognized, remainder, period for recognition	30 years
Wyoming Refinery Two | Waste Water Treatment System
Long-term Purchase Commitment [Line Items]
Environmental remediation accrual	$ 11,600,000
Wyoming Refinery
Long-term Purchase Commitment [Line Items]
Loss contingency, range of possible loss	100,000
Tesoro Corporation | Indemnification Agreement
Long-term Purchase Commitment [Line Items]
Deductible for indemnification obligation	1,000,000
Indemnification obligation cap	$ 15,000,000