The balances object

The balance summary gives an overview of the "available", "pending", and "current" balances for various accounts a customer has. By default, it will only return the "default" account for each currency a customer holds. To return other accounts, include an "accounts" query parameter to the request containing a comma-separated list of account you would like balance summaries for.

{
  "usd": {
    "default": {
      "available": "20.00",
      "pending": "80.00",
      "current": "100.00"
    },
    "california_funds": {
      "available": "10.00",
      "pending": "0.00",
      "current": "10.00" 
    }
  }
}