$100B sounds like a lot of money to any sane human being, but for the T-Bill market it's really a drop in the ocean. Current T-Bill Market cap[1] is 29 Trillion give or take a little, so $100B is about 30bps of the total. Would nudge the market a little bit, but not that much.

[1] Here's my source and they should of course know https://fred.stlouisfed.org/series/MVMTD027MNFRBDAL