That's the total projected pension cost for each year from now until the last currently retired employee dies, which may be 30+ years from now. So it's not debt

That's the total projected pension cost for each year from now until the last currently retired employee dies, which may be 30+ years from now. So it's not debt, per se, since that cost is amortized over the same 30+ years. It's a projection of the total cost over that time period.