This isn't the impression we wish to leave you with, @sijprop1.

At this time, there's not a way to add a custom Detail Type in QuickBooks Online. I'm going to submit feedback to our Product Development Team about bringing in a feature that will allow this to happen, You can visit our Blog to see new features and upcoming updates to our Products. In the meantime, here are a few Community Articles that you may find useful:

• Detail Types in Chart of Accounts
• Add an account to your Chart of Accounts
• Create subaccounts in your Chart of Accounts

If you have any further questions or concerns, please don't hesitate and reach back out to me. I'm always here to help you.