It's not all floating. As I mentioned, the PBO study found that an increase in interest rates in one year would have an impact of $4.5 billion, but over five years, it would be $12.8 billion, and that's because it takes time for that longer-term debt to roll over. It wouldn't be immediate, but even $4.5 billion is significant. Once rates start rising, they're not going to stop at the 1% scenario that was in the PBO's report. Once rates start rising, there's a potential there for them to rise quite significantly.
On March 18th, 2021. See this statement in context.