Casualty insurance, also called property liability insurance, differs from other types of insurance in that it helps the policy holder pay for the medical or related expenses incurred by another party instead of paying for the policy holder's expenses. It is commonly included as part of rental or auto insurance.
Most insurance functions as a means of financial recourse for the person holding the policy. For example, medical insurance helps to cover the costs of health care expenses that the policy holder experiences during or after receiving medical attention. Similarly, auto insurance covers the costs of replacing or fixing a car when the owner gets into an accident. Casualty insurance functions in essentially the opposite fashion, in that the policy owner does not receive the money but pays it to another party after he or she is injured.
One common scenario in which casualty insurance comes into play is when a person injures herself while on another person's property. If the property owner is found to be at fault, such as by failing to clean up a walking hazard or by some other form of negligence, and the person injured experiences medical costs, casualty insurance helps the property owner pay for the portion of those costs for which she is liable.