How many edges are cut in a balanced partition of a graph?
Even in the current updated version of the question, it still remains ill defined. There many different ways by which you can partition a graph into symmetric (or balanced if you like) clusters. One question that you might have in mind but have problem expressing is the minimum multisection (or partition): Given a graph $G$ find a symmetric partition $P$ of its vertices such that it minimizes the edges between different clusters.

In which case the answer is that the problem is NP-hard [1] and moreover it is NP-hard to approximate within a constant factor [2].

[1] L. Hyafil and R. L. Rivest. Graph partitioning and constructing optimal decision trees are polynomial complete problems. 1973.

[2] K. Andreev and H. Racke. Balanced graph partitioning. 2004.