You seem to have wildly inflated the pension obligations of GM. The most recent figures that I've been able to find is that it stands at around $71 billion for the U.S. and around a $135 billion world wide.
It depends on how the accounting is done. Pension obligations are an odd expense because they are charged every year. It doesn't work the same way as other business expenses.
Suppose I buy a truck for my business. The cash cost is $50,000 and I plan to use it for 5 years. On the balance sheet, I write it down as a $10,000 expense every year for the next 5 years. Understanding how things show up on a balance sheet, how would you find the total cost of pension obligations? You can't. The pension obligation might be $10,000 per year until the end of time. If you expect the company to exist for another 5 years, you could say the total pension obligation is $50,000. If you think the company will be around for 10 years, it would be $100,000.
Things like pensions generally show up on the balance sheet as "other liabilities." If we look at GM's balance sheet, the other liabilities are about 8.5 billion per year.
https://www.google.com/finance?q=NYSE:GM&fstype=ii&ei=hXmWU4DVN-KYiQKNoQE
Pensions sometimes also go into the "long term debt" category. There are a lot of different ways the accounting can be done, but it always shows up in the "total liabilities."
I expect GM to be bailed out again and again and again, so I assume those pension liabilities will go on for many years.
I'm not saying GM is uniquely burdened with pensions. Lots of companies have huge pension liabilities. The difference is that companies like Toyota are not unionized, so they can reduce pensions or do lump sum buyouts to reduce the burden as it becomes a problem. GM is heavily unionized, so there's almost no way to reduce the pension burden without going through bankruptcy. GM workers would go on strike, and I don't blame them, but the strike would quickly lead to bankruptcy, then bailout, and we get to start the cycle all over again.
There are similar accounting arguments related to social security and medicare. People on the right generally assume Americans will live a long time, and that's how we get estimates from 100 to 200 trillion dollars of liabilities as baby boomers retire. Liberals tend to assume everyone will be dead before age 70, so cost estimates from the left tend to be much lower. Neither argument is less valid than the other. Nobody knows how long people will live or what future governments will do about these expenses. Maybe the next president will be completely insane and the government's unfunded liabilities will shoot up to 500 trillion. Maybe the next president will somehow abolish medicare and we would have very few unfunded liabilities. Anything is possible.