bright light off I-40 and Mustang Rd in Yukon, OK

I was driving westbound on I-40 heading towards Yukon from Bethany.  It was dark outside (maybe 8 or 9pm?) and at one point, I noticed what appeared to be an airplane flying very low. 
Then about five minutes later, it caught my eye again because it was still very low and didn’t appear to have moved so I remember thinking it must be flying very slow.  I watched it for a while and then decided it must be a helicopter that was hovering in one spot, but I began to notice that it was very large, much larger than a helicopter. 
I turned off my radio and opened the car window to listen for the sound of a helicopter and heard absolutely nothing.  The object was a very bright light and was hovering over the Xerox building on Mustang Road. 
I rolled the front passenger window all the way down to get a better look.  The light was so bright and I could only see the round light; no metal, no real shape, just a bright white ball of light.  It was huge; about the size of a 3 story house.  It was hovering about 100 feet above the parking lot and it did not make a sound. 
I suddenly realized I had slowed down to about 35 mph on the highway and quickly glanced in my rearview mirror.  The cars behind me and in front of me were also traveling very slow and the two cars in front of me took the Mustang Road exit.  I traveled on towards Yukon. 
On my return trip approximately 15-20 minutes later, it was gone. There were no reports on the local news.
Witness indicates that the date of the sighting is approximate.  PD