In my opinion, one of the most concise and easy to understand ways of documenting what individual processes should exist is by creating a Use Case Diagram.  First, consider that you can usually use a process flow or a use case interchangeably to model a process.  Both have the ability to show user/system interaction and have splits and joins in the process.  Use Cases do this by using Alternative Flows.  Use Cases are a bit more limited if you have many actors involved, but this is sometimes good as is focuses the "view" of your modeled process to an actor and system, and then treats all other workers and systems and secondary actors (without giving details of how they provide the necessary information or input to the use case).

Since both Process Flows and Use Cases can be used to represent you processes, a Use Case Diagram gives you a clean, high-level, graphical view of the processes that bring value to the user.  It also displays how some use cases (or processes) can include or extend others.

Hope this helps!