Quote from wikipedia:
The Boeing P-8 Poseidon (formerly the Multimission Maritime Aircraft or MMA) is a military aircraft currently being developed for the United States Navy (USN). The P-8 is being developed by Boeing Defense, Space & Security, modified from the 737-800. It is intended to conduct anti-submarine warfare (ASW) and shipping interdiction and to engage in an electronic intelligence (ELINT) role. This will involve carrying torpedoes, depth charges, SLAM-ER anti-ship missiles, and other weapons. It will also be able to drop and monitor sonobuoys. It is designed to operate in conjunction with the Broad Area Maritime Surveillance unmanned aerial vehicle.