You can certainly find estimates that imply total U.S. energy subsidies are north of $100 billion a year, but I haven’t seen any estimates that look rigorous or convincing. This study put out by (or linked from) EarthTrack looks at least somewhat more respectable; it finds that total U.S. subsidies are $37-63 billion per year. But notice that much of this is of an indirect nature — more than a third comes from the estimates of defending Persion Gulf oil shipments — and it is unclear who these indirect subsidies are supporting. Securing the Gulf arguably subsidizes the world oil market — U.S. consumers may benefit, but so do all other world consumers. Further, what percentage of our military expenses should be counted as an energy subsidy? We have many strategic objectives beyond energy policy when we deploy forces in the Middle East (or elsewhere).