A proposed nuclear power plant will cost $2 billion to build and then will produce cash flows of $280 million a year for 15 years. After that period (in year 15), it must be decommissioned at a cost of $880 million. What is project NPV if the discount rate is 5%? What if it is 18%? (Negative amounts should be indicated by a minus sign. Do not round intermediate calculations. Enter your answers in billions rounded to 3 decimal places.)