<p>I am making a strong effort to discipline my projects and create a Vision/Scope document at the onset.  Included in this are the use case diagrams.  Just listing out the use cases has really helped me fully see all the requirements that the customer is asking for, and it has opened up dialog.</p>

<p>I am wondering about how detailed the use case should be.  If I am making a web application and the user will login to see a report, do I list all the columns on the report in the use case description?</p>

<p>If not, then when would I document those details?</p>

the advantage of use-case diagrams is that they are simple and end-users can read and understand them
the columns to go on a report are part of a design or requirements specification (details of a feature, in agile terms) and do
not
belong on a use-case diagram
anything that clutters the use-case diagram belongs somewhere else
where? it doesn't matter, as long as it's a consistent place and you know where to find it ;-)
to remind people what a use-case diagram looks like - and why there is no room for spurious details -
(source:
agilemodeling.com
)