The thing is, a company pumps oil out of Alaska. The price of crude worldwide is, let's say, $50 per barrel. That company is not going to turn around and say, "Hey, it's American oil, let's sell it to the U.S. for $35 per barrel." They are going to put it on the global market and get as high a price for it as they can, because that's what they're in business to do.
It will be on the global market, but when it is purchased the transportation costs will be lower because it is domestic.
Per how stuff works :::
Distribution and marketing - Crude oil is transported to refineries, and gasoline is shipped from the refineries to distribution points and then to gas stations. The price of transportation is passed along to the consumer. Marketing the brand of the oil company is also added into the cost of the gasoline you buy. Together, these two factors account for about 13 percent of the price of gasoline.