No point in selling the GPU division for that little money. Maybe Intel can get a licensing deal at that level though, with either AMD or nVidia. AMD will need their GPU division for their next gen Zen based APUs and consoles, unless they get some serious money for it.
Intel would need some 3-4 years to integrate AMD IP on whatever chips they are developing on their pipeline. Given the improvement rates of Intel IGPUs, I don't think there will be much advantage for AMD, if any advantage at all, in terms of iGPU performance at the end of this time frame.
I also think you are overestimating what AMD is calling little money today. With the company bragging about deals that should make some 50-100 million in operating profits per year, 1 billion of cold, hard cash is a lot of money.