Nov 18 (Reuters) - The U.S. Congressional Budget Office said it would publish a complete cost estimate for President Joe Biden"s "Build Back Better" bill on Thursday afternoon. The $1.75 trillion proposal aims to expand the social safety net in the United States and boost climate change policy. The CBO, a nonpartisan arm of Congress, is expected to provide revenue scores for the IRS and drug-pricing provisions, Democratic lawmakers have said. If passed by the House of Representatives, the social policy legislation would move to the Senate, also narrowly controlled by Democrats, where Majority Leader Chuck Schumer wants to enact it before the Nov. 25 Thanksgiving holiday.