Beleaguered retailer Sears Holdings Corp said on Friday it would cut costs by $1 billion and reduce debt and pension obligations by at least $1.5 billion this year, sending its shares soaring as much as 40 percent. The company also said it had sold five Sears full-line stores and two Auto Centers for $72.5 million in January, and had engaged Eastdil Secured to raise at least $1 billion from the sale of its real estate.