Writing down a merger/acquisition is probably the main scenario where this could extend to the billions.

I don't have an exact list but I think you'll see differences of that order in the years following big acquisitions like AMD / Xilinx for this sector.

A very recent example - but the other way around - is Credit Suisse which is going a paper accounting profit of $14bn in Q1, while also having basically gone bankrupt. In addition UBS is also going to post a $53bn paper profit in Q2, without actually having “earned” any surplus money from acquiring Credit Suisse…

Matt Levine goes into the gory detail: https://archive.is/0T1CG