  The Tutte polynomial is a well-studied invariant of graphs and matroids. We
first extend the Tutte polynomial from graphs to hypergraphs, and more
generally from matroids to polymatroids, as a two-variable polynomial. Our
definition is related to previous works of Cameron and Fink and of K\'alm\'an
and Postnikov. We then define the universal Tutte polynomial $\T_n$, which is a
polynomial of degree $n$ in $2+(2^n-1)$ variables that specializes to the Tutte
polynomials of all polymatroids (hence all matroids) on a ground set with $n$
elements. The universal polynomial $\T_n$ admits three kinds of symmetries:
translation invariance, $S_n$-invariance, and duality.
