I received a lump sum severance payment, with the typical withholdings for federal, state, medicare, and social security. I was under the impression that a company shares some of that responsibility and pays a portion of those taxes deducted from my check. It looks like i'm paying for all of it in the payment slip.
Unless the values of Medicare and SS went up as a percentage of your income, then the values are probably correct.
Your employer pays half of your medicare and SS tax, and the amount you see on your stub is the other half (you do not typically see the employer's amount on your paystub). They are NOT paying a portion of your federal or state/local income taxes.
Also, the amount of federal tax withheld might be different, since it's treated as supplemental income (like a bonus) and not periodic income, so there's no practical way for them to precisely calculate the right amount of marginal tax to withhold, and they'll just withhold 25% in federal tax (assuming the severance amount is less than $1 Million). You will get or pay any difference to your marginal tax bracket when you file.