60-DAY NOTICE PERIOD
60-day notice period is NOT part of severance period, whether it's working or non-working. You are still a WF employee during this period and cannot accept another role, unless you RESIGN and forfeit remaining 60-day period and any severance you would had rec'd otherwise. (I was laid off and, within 60-day notice period, I was offered internal role. I had to resign from previous role (bc I was still an employee and in that role, even though non-working during 60-day notice period).
SEVERANCE PERIOD
Severance period begins AFTER 60-day notice period. You are no longer a WF employee during severance, but do enjoy certain benefits until severance ends (e.g., medical, if part of your prior elections). You cannot contribute to 401K, etc. You CAN accept a new job outside of WF during severance and collect all of your severance, regardless of overlap. However, if you accept new internal WF role, your severance ends (you can keep what was paid out to you until your start date in new role).
PLEASE read the Employee Handbook. All these details are covered.