(Reuters) - Facebook plans to file documents as early as Wednesday for a highly anticipated IPO that will value the world's largest social network at between $75 billion and $100 billion, the Wall Street Journal cited unidentified sources as saying on Friday. Morgan Stanley is a strong front-runner to be the lead underwriter on what would be one of the largest initial public offerings in U.S. history, the Journal cited its sources as saying. Goldman Sachs is expected to play a significant role in the deal too, the newspaper added. A Facebook spokesman declined to comment. ...