GM and rival Ford Motor (F), rebounding from their near-death experiences during the financial crisis, are eager to rid their balance sheets of the huge pension obligations that Wall Street views as onerous debts weighing on their credit ratings and stock prices. So this spring they came up with an ambitious solution: buy out the lifetime pension payments due 140,000 salaried retirees. With both carmakers suddenly flush with profits--GM and Ford made $9.2 billion and $20.2 billion, respectively, in 2011--it seems like a smart way to remove decades of uncertainty from their finances.