The document that details the syllabus for the UPSC Civil Services Examination is the UPSC Notification, which is released annually. This notification outlines the examination structure, including subjects, type of questions, and important dates. It is crucial for candidates to thoroughly review this document to understand the examination pattern and prepare accordingly. By grasping the syllabus, aspirants can effectively focus their studies on relevant topics and avoid wasting time on content that is not pertinent to the examination.