For the first time in history, the United States' credit rating has been downgraded. Experts say it's still too soon to tell what that means for your loans, credit cards and stocks.  In an unprecedented move, Standard and Poor's, one of the world's major credit rating agencies, downgraded the U.S.'s rating from AAA. That's the highest rating possible. It's now at AA+ -- still strong, but not the best.  Analysts agree that you might see short-term credit movement with adjustable rate mortgages and credit card rates going up. Financial analyst Dave Petso says that this actually could be a good thing.  He doesn't see the downgrade affecting the average American or Idahoan all that much.  An S&P official said there's a one in three chance the U.S. credit rating could be downgraded another notch, if conditions erode over the next 6 to 24 months.