The fact that you think that's a big number just underscores how dire Europe's security situation is at the moment. One hundred billion Euros sounds like a lot, but China spends two and a half times that much on defense every single year, the U.S. spends 10X that much every single year, and even the Russians spend more than that every single year. Nevermind the fact Europe needs to play catch up here, not just keep pace.
Wikipedia says Russia spent 100 billion in 2023, so increase of 100 billion should be more than that don't you think? Are you misinformed or deliberately lying?
You have to adjust figures for PPP, or Purchasing Power Parity, due to exchange rate differences. In 2024, Russia's PPP adjusted military spend was somewhere between $300B and $400B [1][2]. Their technology is also vastly superior to Germany's and they have a much larger personnel. It doesn't matter how much you spend if you don't get your money's worth.
3 days after the start of the invasion, Germany announced a €100 billion increase to military spending.
https://en.wikipedia.org/wiki/Zeitenwende_speech