Delta Air Lines this week entered into a definitive agreement with Airbus to buy 50 widebody aircraft during the next several years,

according to a filing with the U.S. Securities and Exchange Commission. Under the agreement, Airbus will begin delivering 25 Airbus A350-900 aircraft in 2017 and 25 A330-900neo aircraft in 2019. The A350-900 craft will replace Boeing 747-400 aircraft largely on long-range routes between the United States and Asia. The A330-900neo aircraft will replace Boeing 767-300ER aircraft and will be used on "medium-haul transatlantic markets as well as select routes connecting the U.S. West Coast and Asia," according to Delta. Financial details were not disclosed in the filing, though media reports have priced the order at about $14 billion, not taking into consideration discounts usually offered on orders of that size.