In a simple conversion, imagine that the spilled oil was contained in standard 1-gallon milk jugs. 184 million of them. If the entirety of oil that was spilled was in this form, the amount of oil actually spilled may become more understandable.
Set side by side, the 184 million oil-filled jugs would cover an area of approximately 1.36 square miles. This amount of 1-gallon containers would be enough for every resident of the 12 most populous US states (2/3 the population of the country) to carry one in their hand simultaneously.