WDFN via some Lansing reporter:
Michigan - MSU - Nebraska - Iowa - Minnesota - Northwestern
OSU - PSU - Wisconsin - Purdue - Indiana - Illinois
It seems like they tried to split the rivalries, but PU and IU are both in the one division and Iowa and Minnesota in the other. Seems like they should swapped one each of those to keep all these inter-divisional rivalry games as the season finale.
It would seem that the Michigan division might have more depth while the OSU division has a tougher high end.