Hmm. US "federal" budget. You're using the 2015 estimate, checking states budgets... total states spending estimate of 1.83 trillion in 2015, minus 0.59 trillion federal contribution. So combined budget of the USA as a nation in 2015 estimate 5 trillion. Divide by 240 million adult citizens, 20k/y each.
However: UBI would not be giving 20k to every adult citizen. A sensible UBI would be set to the poverty threshold, which 2015 estimate is 12k (averaged, will vary by state). So actually a little over half the US federal and states combined budget should _at most_ go to UBI. Note that current US federal budget spending on SS/unemployment/labor in 2015 already 33%.
A further requirement for UBI to be implementable in the US would necessarily be economic reform to ensure that those who have no need of the UBI (a wild hypothetical appears: those with more than median household income) would return their UBI and fund others to the government via the usual higher-income taxation methods. This would further reduce the budgetary impact.
Inb4 "state vs federal": UBI by definition only works if it is embraced "universally". Given the way the US operates its spending, for UBI to be implementable in any given state, that state's government will have to come to an arrangement with the federal government on how to fund it. This means UBI may not happen in (part of) the US, but that's a political problem not an economic one.
Inb4 "my taxes": you are _already_ paying. And you pay not just in taxes but in the levels of crime, health and liberty you are prepared to accept or surrender.
UBI reduces crime by reducing poverty (indeed, effectively eliminating the latter barring acute/outlier circumstances, and less crime means less taxes you need to pay to combat crime and heal those injured - directly and indirectly - by crime and poverty).
UBI increases liberty by reducing government power (e.g. its ability to control and micromanage distribution, of the taxes you provide for the common welfare, to favor special interest groups).
I hope this helps clear up misconceptions about UBI at least a little.