WASHINGTON —The Senate has approved a bill overhauling the rules on secret government eavesdropping and granting immunity to telecom companies that helped listen in on Americans after Sept. 11.

The Senate passed the bill Wednesday, 69-28. It turned back three amendments that would have watered down, delayed or stripped away the immunity provision demanded by President Bush.

When the president signs the bill, as expected, it will effectively dismiss some 40 lawsuits filed against telecommunications companies for alleged violations of wiretapping and privacy laws.

The bill’s passage ends almost a year of political wrangling over eavesdropping rules.