There's no such thing as a set schedule. You joined a company with about a quarter million employees, give or take. They are divided up into large business units, each going at its own pace on its own schedule, and layoffs can come, or not come, at any time.
Welcome, btw. The words I can offer you are this: do well at your job, always seek to enjoy it, and look for something else if you don't. If there's any consolation, I'd b say that new hires (non-union) are not targeted for layoffs. It's those who have been around the block a few times and are making more money. Face it: you're cheap compared to them.
Best of luck!