I would stay away from having red because it draws too much attention. There's a similar question to this where the answer elaborates on why you shouldn't use red: Preferred format to display negative currency? Like what was mentioned before as well as the linked question, you should display negatives in brackets.
Here are some alternatives to show the users which transactions are incoming and outgoing.
You can use something similar to a "journal entry." In a journal entry, the amount column is split up into "Debits" and "Credits" or in your case, "Incoming" and "Outgoing."
You can also have a column to show if the transaction says "Debit" or "Credit" but I prefer #1 over this.
Also, if your table is really long, I suggest to have filter for the table if you don't already. For example, you can use a filter to show all transactions, only debits or only credits.
I've designed transaction tables before and had to research a bit of accounting, but like mentioned previously, it's a lot easier to ask your users. They probably use a different vocabulary as well (e.g. "Credits" vs. "Incoming")
As a side note, I try to avoid using red and green if they're the only indicators of information. They don't really help when one of your users is colour blind.