E=MC^2 so… we assume 371.38g of beer (I took the weight of 12 fluid ounces of water and did some guestimation since beer isn't pure water)
3.3378e+16 joules
2.4618e+16 foot-pounds
7.9775e+3 kilotons of TNT
7.9775 megatons of TNT
3.16362398 x 10^13 BTU
So
9.27166665 × 10^9 kwh or 7.97753345 × 10^12 kilocalories
Which is 9,271,666,650 kwh where the U.S. used an estimated 3.741 trillion kWh in 2009. So .002% of the U.S. energy consumption for 2009. Now... that's 1.243350979e+10 horsepower hours.
It’s also 9,271.66665 jigawatts Marty
UPDATE July 29th, 2016
So I was thinking about what such a device as the Mr. Fusion would mean as far as power for space travel...
SpaceX's Falcon 9 rocket carries 395,700kg of fuel (119,100 Kilograms of Rocket Propellant 1 and 276,600kg of Liquid Oxygen). Let us assume that a Mr. Fusion operated at 13% efficiency (roughly what commercial solar panels operate at currently), this would give us the equivalent energy of 1.1050e+6 megatons of TNT which is 1,284,255.55 jigawatts Marty!
So mass equivalent to the weight of fuel in a a Falcon 9 would provide 1,284,255.55 terawatt hours of energy for our spacecraft at 13% efficiency. The ENTIRE PLANET used an estimated continuous average of 12.3 terawatts in 2013 (as in 12.3 terawatts being drawn every second of every day during the year) meaning a bit shy of 12 years worth of electricity for the planet, remember that's with 13% efficiency on that Mr. Fusion.