It can depend on your role in a project and what standard practice is in your area. It's really not helpful to ask in the general sense.
For example, in most of Canada if you're doing steel work as the primary design engineer you'll likely show the major members, maybe some conceptual connections and the connection loads. Beyond that you'll show details of non-standard areas if you think they're necessary and things like base plates and the like.
Once you've done that the fabricator will come up with fabrication level drawings that include connections and full detailing of the individual members. The fabricator or contractor would prepare erection drawings at this stage as well.
In other parts of the world, though, the primary design engineers would be responsible for the connection details, or even all the way down to full on fabrication details.
Requirements for detailing will also vary depending on the type of work, materials being used, the difficulty of the work (if it's heavily non-standard you have to detail more). With some types of construction you can refer primarily to standard details or notes, other types you'll need to work out individual solutions to problems. It can also depend on the contractors, level of supervision and all sorts of other things.
Basically you detail to the minimum level that will clearly communicate your design work to whoever does the work. You don't do any more than that because (a) you don't want to confuse people (b)you don't want to waste hours on work you don't need to do (c) you don't want to accidentally take responsibility you don't have to by detailing connections or other things that someone else should be responsible.
On the subject of (c), you have to be careful. On steel drawings I've seen several people put too many details on their drawings and end up with trouble. Basically, a draftsman draws up the drawings and includes a preliminary detail of a connection. Then the engineer looks at it, sees that the concept is fine and tells himself that the fabricator will be responsible for that design and doesn't check it. However, because the draftsman included dimensions there are enough details given that the fabricator can build exactly to the drawings. If there is a stamped drawing with connections fully detailed and no other explanation, you've taken responsibility for them. So if you work in an area where it's standard for the fabricator to design connections, be careful what information you provide. I won't put any dimensions or thicknesses on a conceptual connection detail unless I have a gap between members that I need, or if I am including a maximum or minimum value for some dimension. Personally, I also have a standard note I put on my drawings saying that any connection details shown are conceptual in nature and the fabricator is fully responsible for all connection design. It makes things easier if there are ever arguments.
