By Chuck Mikolajczak NEW YORK (Reuters) – The U.S. dollar index retreated from earlier highs and fell on Tuesday as U.S. equities shook off an early risk-off mood and turned positive, but the greenback managed to hit its highest level in 20 years against the Japanese yen. Stocks on Wall Street advanced in the early portion of trading, reversing course after each of the major indexes on Wall Street opened with sharp losses and the Nasdaq lost more than 1%, dampening the appetite for the safe haven dollar. The dollar index fell 0.117% at 102.340, with the euro up 0.07% to $1.0702. The yen weaken…