Payment balances track the movement of funds related to a single payment. Funds come in via Payments but can also leave via Refunds, Disputes, Fees, and Payment Transfers. Payments track these changes through balance change objects. The current state of payment funds is given by the balance object which is the sum of all of the balance changes made against a payment.
GET /payments/:paymentId/balances
GET /payments/balances/changes/:balanceChangeId