Pegar valor de object Paypal

[Kelven 1]

Bom dia pessoal tudo bem?!

Então eu estou com o seguinte problema, fiz a integração do API do PayPal para poder ter o retorno do email do pagamento, ai eu pego o email do pagamento da seguinte forma: 

document.getElementById('demo').innerHTML = details.payer.email_address;

o problema é que eu queria pegar também o valor q foi pago, mas já tentei de todas as formas pegar esse object mas não consigo, os retornos do api são assim:

{
  "id": "5O190127TN364715T",
  "status": "COMPLETED",
  "payer": {
    "name": {
      "given_name": "John",
      "surname": "Doe"
    },
    "email_address": "customer@example.com",
    "payer_id": "QYR5Z8XDVJNXQ"
  },
  "purchase_units": [
    {
      "reference_id": "d9f80740-38f0-11e8-b467-0ed5f89f718b",
      "shipping": {
        "address": {
          "address_line_1": "2211 N First Street",
          "address_line_2": "Building 17",
          "admin_area_2": "San Jose",
          "admin_area_1": "CA",
          "postal_code": "95131",
          "country_code": "US"
        }
      },
      "payments": {
        "authorizations": [
          {
            "id": "0AW2184448108334S",
            "status": "CREATED",
            "amount": {
              "currency_code": "USD",
              "value": "100.00" ESSE É O VALOR QUE EU QUERIA PEGAR
            },
            "seller_protection": {
              "status": "ELIGIBLE",
              "dispute_categories": [
                "ITEM_NOT_RECEIVED",
                "UNAUTHORIZED_TRANSACTION"
              ]
            },
            "expiration_time": "2018-05-01T21:20:49Z",
            "create_time": "2018-04-01T21:20:49Z",
            "update_time": "2018-04-01T21:20:49Z",
            "links": [
              {
                "href": "https://api.paypal.com/v2/payments/authorizations/0AW2184448108334S",
                "rel": "self",
                "method": "GET"
              },
              {
                "href": "https://api.paypal.com/v2/payments/authorizations/0AW2184448108334S/capture",
                "rel": "capture",
                "method": "POST"
              },
              {
                "href": "https://api.paypal.com/v2/payments/authorizations/0AW2184448108334S/void",
                "rel": "void",
                "method": "POST"
              },
              {
                "href": "https://api.paypal.com/v2/payments/authorizations/0AW2184448108334S/reauthorize",
                "rel": "reauthorize",
                "method": "POST"
              }
            ]
          }
        ]
      }
    }
  ],
  "links": [
    {
      "href": "https://api.paypal.com/v2/checkout/orders/5O190127TN364715T",
      "rel": "self",
      "method": "GET"
    }
  ]
}

alguém sabe me dizer como posso pegar o Value ??

[ShadowDLL 2]

Tente com o código abaixo:

details.purchase_units[0].payments.authorizations[0].amount.value