When you create an account, you can choose from different account types (expense, income, liability, etc.). You can also choose from detail account types.
A detail account type is a predetermined sub-category that ensures the account appears in the correct place according to GAAP (Generally Accepted Accounting Principles).
For example, all cash or cash equivalents are grouped together on the Balance Sheet under Assets, and sub-categorized as Current Assets. Choosing the correct categories also enable the accounts to be placed in the correct positions on the Balance Sheet or Profit and Loss Statement.
Detail types are predefined and you cannot edit them. If you can't find the exact type you are looking for, select the detail type that is the nearest match.