What would you do with $700 Billion?
Retric: Invest 50 billion and spend each years profit trying to build a real working fusion power plant, (~1 new ITER style plant design per year pick the best one and build it every 5.) when that's working invest the 50billion in power plants and keep growing till all the worlds energy needs are met.  I expect 20 - 30 years till first one works and then massive ramp up.50 billion 3rd world sweat shops to jump start the worlds economy.100 billion, retro fit a lane on all US highway's with electric grids / contacts so there is no need for battery systems and we can go electric now.  I would start by targeting the commercial trucking industry and then move to cars.1billion fun money for me.And I don't know about the rest.