unable to parse the JSON returned by AWS.EC2.describeInstances() method in nodejs API

This is my code

var AWS = require('aws-sdk');
AWS.config.region = 'ap-southeast-1';

var uuid = require('node-uuid');
ec2 = new AWS.EC2({apiVersion: 'latest'});


AWS.config.update({accessKeyId: xxxxxxxx, secretAccessKey: yyyyyyyyyyy});
AWS.config.update({region: 'zzzzzzzzzzzzzz'});

var util = require('util');
var opsworks = new AWS.OpsWorks();
var cloudformation = new AWS.CloudFormation();
var cloudwatch = new AWS.CloudWatch();

function listInstances(callback){
new AWS.EC2().describeInstances(function(error, data) {
    if (error) {
        callback(error);
    } else {
        callback(util.inspect(data, {depth: null})); //this returns a full fledged JSON response on the console

}

});
}

//Test above methods
listInstances(callback);


function callback(data){
  console.log(data);
}

I tried parsing the JSON response by replacing the line

callback(util.inspect(data, {depth: null})); 

with

JSON.parse(data);

I get the following error

{ [SyntaxError: Unexpected token o] statusCode: 200, retryable: false }
{ [200: null]
message: null,
code: 200,
time: Tue Jul 22 2014 22:59:42 GMT+0530 (India Standard Time),
statusCode: 200,
retryable: false }

i tried using eval() to parse it and i got the following error

[SyntaxError: Unexpected identifier]

Am I doing anything wrong, should I be parsing the JSON response using any other logic?

Please excuse my ignorance if any since I am new to both node.js and AWS