California Code, Code of Civil Procedure - CCP § 2017.210

A party may obtain discovery of the existence and contents of any agreement under which any insurance carrier may be liable to satisfy in whole or in part a judgment that may be entered in the action or to indemnify or reimburse for payments made to satisfy the judgment. This discovery may include the identity of the carrier and the nature and limits of the coverage. A party may also obtain discovery as to whether that insurance carrier is disputing the agreement's coverage of the claim involved in the action, but not as to the nature and substance of that dispute. Information concerning the insurance agreement is not by reason of disclosure admissible in evidence at trial.