WASHINGTON (Reuters) - Negotiators in the U.S. Congress have reached agreement on a $1 trillion spending bill for consideration this week in an effort to stave off another government shutdown until at least September 30, Senate Appropriations Committee chairwoman Barbara Mikulski said on Monday. The bill, which is expected to be filed at 8 p.m. EST (0100 GMT), eases some of the across-the-board "sequester" spending cuts by boosting spending on domestic and military programs during the 2014 fiscal year by $45 billion. Mikulski told reporters that the measure will reverse planned military pension cuts for disabled veterans and does not contain any provision that blocks the implementation of "Obamacare" health insurance reforms. (Reporting by David Lawder, editing by G Crosse)