Answer by
LeheckaG (1826)
Yes,
Severance pay ( excluding death, disability, retirement, or other involuntary severance ) is generally treated as taxable income or wages for federal & state income/withholding & FICA/Medicare/Social-Security taxes.
There are various other "bona fide" or "qualified" deferred compensation plans recognized by the IRS, for which compensation might not be treated as "severance pay".