No state income tax on severance in Texas
Texas has no state income tax, so severance is taxed federally only: a flat 22% federal supplemental withholding (37% above $1 million), Social Security 6.2% up to the annual wage base, and Medicare 1.45%. That's a real advantage — the same $30,000 package nets you roughly $2,000–3,500 more in Texas than in a high-tax state.