Your hearing aids can be used as a headset with any phone as long as the phone provides the Hands Free Profile (HFP), this includes landline or cordless phones (e.g. DECT standard).
NOTE: Many (older) landline phones only support older Bluetooth® versions < 2.1. Also, they often do not provide HFP but only HSP (HeadSet Profile), which will not work with your hearing aids. Please check your phone’s Bluetooth® specification in the user guide.