Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Basic:
Net earnings attributable to Tesoro Corporation stockholders	$ 387	$ 218	$ 443	$ 325
Weighted average common shares outstanding (shares)	139.6	142.6	139.5	142.1
Basic Earnings Per Share (dollars per share)	$ 2.77	$ 1.54	$ 3.18	$ 2.29
Diluted:
Net earnings attributable to Tesoro Corporation stockholders	$ 387	$ 218	$ 443	$ 325
Weighted average common shares outstanding (shares)	139.6	142.6	139.5	142.1
Common stock equivalents (stock equivalents)	0.9	1.8	1.7	2.1
Total diluted shares (shares)	140.5	144.4	141.2	144.2
Diluted Earnings Per Share (dollars per share)	$ 2.75	$ 1.52	$ 3.14	$ 2.26