I'm using:
\documentclass[journal,transmag]{IEEEtran}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{breqn}
\begin{document}
\begin{align}
something&\left(\sum_{n}\right.\nonumber\\
&\quad\left.\vphantom{\sum_{n}}+y\right)/\left(x\right)^2.
\end{align}
\end{document}
With \vphantom{\sum_{n}}
I get the big right parenthesis in the second line which is what I want. How can I get a larger division symbol as well?