type: string
enum:
  - CARD_TRANSACTION
  - CARD_TRANSACTION_LINE
  - FX_FEE
  - REIMBURSEMENT
  - REIMBURSEMENT_INVOICE_LINE
  - REIMBURSEMENT_INVOICE_LINE_SPLIT
  - MILEAGE_LINE
  - PER_DIEM_LINE
  - INVOICE
  - INVOICE_LINE
  - UNKNOWN_DEFAULT_OPEN_API
description: |
  Type of expense (used for both expense headers and lines).

  **Types:**
  - `CARD_TRANSACTION`: Expenses from card transactions
  - `CARD_TRANSACTION_LINE`: Card transaction line items (nested within card transactions)
  - `FX_FEE`: Foreign exchange fee line items (nested within card transactions)
  - `REIMBURSEMENT`: Reimbursement expenses
  - `REIMBURSEMENT_INVOICE_LINE`: Reimbursement invoice line expenses
  - `REIMBURSEMENT_INVOICE_LINE_SPLIT`: Reimbursement invoice line split expenses (nested within reimbursement invoice lines)
  - `MILEAGE_LINE`: Mileage line expenses
  - `PER_DIEM_LINE`: Per diem line expenses
  - `INVOICE`: Invoice-based expenses
  - `INVOICE_LINE`: Invoice line items (nested within invoices)
  - `UNKNOWN_DEFAULT_OPEN_API`: Unknown expense type (fallback for future types)
example: "CARD_TRANSACTION"