My previous company (a large corporation) did 1 week per year you worked there, capped at 4 weeks (one person I know that was laid off was there for 17 years, only got the 4 weeks). They actually used to be more generous but made significant cuts to their severance benefits shortly before layoffs so they could save a bunch of money on it (they also took away 401k match later, reduced PTO days, eliminated bonuses, froze raises, made our health care benefits worse, let tons of people leave without authorizing filling in gaps so many departments became overworked skeleton crews, all sorts of crap to save money).
So at least in that case, it wouldn't have mattered if I asked what their severance policies were while interviewing.