That article is confusing debts with unfunded liabilities, I am afraid. And a closer reading explains the 800k as how much each Taxpayer would owe - if any of this actually made sense.
But, I guess this is not a new idea, here is an article from 2012, back when the scary number was supposedly only 100 trillion dollars.
If you dont want to read the whole thing, here is the part that debunks the myth:
(1) That’s not our debt. Our $16 trillion in debt and our $87 trillion in “unfunded liabilities” represent two very different ideas: real past promises and projected future promises. Real past promises are, well, very real. We have to pay back our debt. Failing to do it would be an illegal and disastrous default. Unfunded liabilities are future promises, and, since they’re not as real, we can change them whenever we want without destroying ourselves. For example, raising the taxable income ceiling and slowing the growth of benefits could reduce the Social Security gap to zero tomorrow.
And that’s if there is a Social Security “gap” to begin with. Technically, it’s not legal for Social Security to have “unfunded liabilities” since it can only pay as many benefits as it receives in earmarked taxes. Both it and Medicare hospital insurance are prohibited from spending money they haven’t collected from specific revenue dedicated to their programs (i.e.: payroll taxes). It is impossible for either to technically be “unfunded”, since they cannot legally outspend their funding.
(2) 75-year projections are scarier than they are informative. Seventy-five-year projections always sound gargantuan because, well, they’re calculated over three-quarters of a century, which is an awfully long time to count anything. But here’s the flip side: In 75 years, our economy will be massive. Growing slowly at a 2% annual average, our GDP would be $66 trillion in today’s dollars in 2087. That’s an incomprehensibly big number, too. Once you run out any number over 75 years, the mind starts to boggle. That’s good for scaring people with mind-boggling numbers, but it’s not so good for informing. When Republicans say unfunded liabilities come out to $520,000 per U.S. household, they’re taking a figure from 2087 and dividing it over a 2012 population to exaggerate. Scary, to be sure, but not very informative.
So to use your analogy, the US mortgage is 28 trillion; this we have to pay back. The other 100 trillion dollars would represent the hot tub, jet skis, vacations and various other things we promised our wives we would buy them someday . If our incomes keep growing, then sure, maybe we will buy all the things we promised; but we are not obligated to. Anyway, I hope at least someone else finds this sort of thing as interesting as I do. Its a massively complex system we live in, and its easy to take it completely for granted.