can I get severance if I retire? Been there for about 20 years.

Unfortunately if you voluntarily leave your employment (i.e. retire), you are not entitled to any termination or severance pay. If the company were to terminate you on a without cause basis you would likely be entitled to a significant severance package. As such, if you have reason to believe the employer might let you go soon, it might be worth it to you to you to continue working until they let you go so you can get your severance entitlements.