After decades of profligate spending, Americans have turned the corner and now are savers. Why? According to Wells Fargo CEO John Stumpf, it's because they seek security more so than yield. But he also points out that while Americans are carrying more aggregate debt than they did 20 years ago, the cost of carrying that debt is back to what it was in the early '90s because interest rates are so low. "People are saving now like they've never saved before," says Stumpf, who also discusses his views on "too big to fail" and the home mortgage meltdown.