Without knowing more information there is no way to know one way or the other. Alot of it's going to depend on your states insurance laws. Some states would require the employer to either help defray the costs, where as others would hold the employer completely responsible, or not at all. You personal insurance policy is a good place to start. Read your policy, if you don't understand something call your agent. There are also other considerations, was the car parked legally, did the employer ask you to run the errand, were you running the errand during business, or was this something you just popped in before/after work on your way home. There's alot of different factors that can be taken into consideration, and most of it's going to depend on your states laws regarding such accidents.