The Boeing Co. has announced a firm order from El Al Israel Airlines for four 777-200ERs. The extended-range passenger jets are worth $850 million at list prices, although customers typically negotiate discounts. Besides the orders that were announced Monday, El Al has taken options for two other 777s and has the right to convert the orders to 777-300ERs, a larger version of the plane. El Al's fleet currently includes four 777s. With the latest deal, Boeing has a backlog of more than 360 777s on order.