CBS issued revised guidance to investors on Friday afternoon, forecasting “a decline of mid-teens” in operating income for fiscal 2008 compared to a year ago. They also said they expect to take a $14 billion impairment charge in the third quarter “to reduce the carrying value of goodwill, intangible assets related to FCC licenses and investments.” Earlier in the day, Sumner Redstone’s National Amusements announced that it will sell $400 million in equal amounts of Viacom and CBS shares in order reduce debt and comply with their credit agreements. The proceeds will bring the company’s debt load down to $1.2 […]