Reuters: A group of large U.S. companies, including the troubled Big Three automakers, on Thursday offered Congress a blueprint for greenhouse gas regulation with looser limits than President-elect Barack Obama has called for. The U.S. Climate Action Partnership, a group of 26 big companies and several environmental organizations, proposed reducing greenhouse gas emissions by 80 percent from 2005 levels by 2050 through an economy-wide cap-and-trade program. “It will not be cheap and it …