I would assume the Marriott - it's in fortress Cen City. There is a Westin Downtown too, kind of old, both are OK - the airport is pretty far away, but safe. Downtown Detroit is the truly the biggest ghost town at night - more unlit sky scrapers than anywhere outside of China.
I thought so too, but this is from the media guide.
Hotel Headquarters on the Road
All hotels are subject to change without notice.
Miami - at Canton
Cleveland Marriott East.................................................................(216) 378-9191
Oakland
Marriott Fremont Silicon Valley ......................................................(510) 413-3700
Arizona
Hotel Palomar Phoenix..................................................................(602) 253-6633
Kansas City
Westin at Crown Center ................................................................(816) 474-4400
San Diego
Omni San Diego ...........................................................................(619) 231-6664
Philadelphia - TBD
Detroit
Westin Detroit Metro Airport..........................................................(734) 942-6500
New Orleans
Marriott at the Convention Center..................................................(504) 613-2888
New York - TBD
Chicago - TBD
Washington - TBD