Executives from Lockheed Martin, Raytheon Technologies and Boeing declined an invitation from Senate Budget Committee Chairman Bernie Sanders (I-VT) and Sen. Chuck Grassley (R-IA) to testify during a Tuesday hearing about waste, fraud, cost overruns and auditing the Pentagon. The senators sent each company a letter explaining the intent of the hearing. "The hearing will focus, in part, on defense contractor cost overruns," the letter said. "Currently, the Pentagon has over $1.8 trillion worth of weapon systems under development, and,...