CHICAGO (AP) -- Union leaders issued a report Tuesday that outlines ways Chicago can save $242 million while also saving the jobs of hundreds of city workers whom Mayor Rahm Emanuel has said he must lay off.The union leaders said at a news conference that the report they delivered to Emanuel's office takes aim at city departments that are inefficient and bloated with far too many managers and a "patronage" system that unfairly awards contracts to "private contractors and contributors" at the expense of the city's union workers.The report was released by the Chicago Federation of Labor and the Chicago & Cook County Building & Construction Trades Council that the leaders say represent 8,000 union workers in the city and is the latest volley in a battle between unions and Emanuel.That battle included Emanuel's announcement this month that after union leaders did not come up with suggestions on how to find the last $10 million of a $31 million budget gap that he was forced to order layoff notices be sent to as many as 625 city workers.Union officials have bristled at the characterization that they dragged their feet and at what they see as an effort to vilify hard-working city workers. And on Tuesday, after handing media members the report, they suggested there's a lot of waste at City Hall that has nothing to do with their rank and file members.They pointed out, for example, that in some departments have supervisors who oversee the work of fewer than two front-line workers."All we were doing was highlighting that you have a lot of people watching workers do work and maybe we should have more people doing the work," said Jorge Ramirez, president of the Chicago Federation of Labor.The report also suggests the city could save about $40 million just by opening up various jobs to competitive bidding between private firms and the unions."Let's get rid of the unfair advantages given to outside contractors and contributors," the report concluded.The report found several ways the city could be more efficient, such filing city notices online instead of in newspapers, coordinating the use of heavy equipment across departments to reduce the number of times the city must rent the equipment, and turning some legal work by private attorneys over to city-employed law clerks.Such measures, big and small, could save up to $165 million, the report concluded.Absent from the report was any mention of work-rule changes that Emanuel has repeatedly brought up in recent weeks. Ramirez said that while he is not necessarily opposed to such changes, it was the individual union locals' place and not his to make them.Emanuel said he appreciated the report, and the suggestions about middle management. But he also left no doubt that he was not about to drop the reforms he's been pushing."When you have the private sector paying time-and-a-half for overtime, why should we pay double-time," he said, according to the Chicago Sun-Times.