The who and where has been decided for some time now. In fact, 14 of 16 games each year are set for the next 10 years.
The first Chi game was in the NFCCG. Just the luck of the way it fell out. Don't like that, we should have won home field advantage. Last year we went because they were a same place finisher in the NFC, who we always play (why we're playing the Redskins and 49ers this year). This season we owe them a trip to Chicago since the last time the NFC North was on our schedule rotation, they played us at our "home" (Tiger Stadium).
Just luck of the draw. I'm sure Philadelphia was sick of coming to the Dome, too, but they won on their 3rd trip.